On February 27, 2008, information was presented to the Advisory Committee on Immunization Practices (ACIP) on the risk of febrile seizures after combination measles, mumps, rubella, and varicella (MMRV vaccine: ProQuad®) vaccination in children aged 12–23 months. ACIP voted to state no preference for use of combination MMRV vaccine over separate administration of MMR and varicella vaccines. Physicians may administer MMRV vaccine or MMR and varicella vaccines separately, according the routine immunization schedule. On February 27, 2008, the Food and Drug Administration approved a revised label for MMRV vaccine to include new and evolving information on the risk of febrile seizures after MMRV vaccination. MMRV vaccine is currently in very limited distribution in the United States; however, some clinics may have MMRV vaccine in stock.
Preliminary results from a Centers for Disease Control and Prevention (CDC) postlicensure MMRV safety study found that the rate of febrile seizures during the 7–10 days after vaccination was about 2 times higher in children who received MMRV vaccine (9 per 10,000 children vaccinated), compared with children who received MMR and varicella vaccines separately at the same visit (4 per 10,000 children vaccinated). The interim analysis of Merck’s postmarketing study showed that during the 5–12 days after vaccination, the rate of febrile seizures was about 2.5 higher in the children who received MMRV vaccine (5 per 10,000 children vaccinated), compared with children who received with MMR and varicella vaccines separately at the same visit (2 per 10,000 children vaccinated).
Sunday, September 28, 2008
AMA and AAHIVM releases coding guidelines for routine HIV testing
The American Medical Association (AMA), in partnership with American Academy of HIV Medicine (AAHIVM), has just released a new CPT Coding Guide to help physicians and their billing staffs become familiar with the proper coding for submitting claims forms related to routine HIV Testing. This Guide was developed to help implement the Centers for Disease Control and Prevention's Revised Recommendations for HIV Testing of Adults, Adolescents and Pregnant Women in Health-Care Settings.
This Guide is the result of efforts by the AMA, the AAHIVM, and several other national partners to help physicians understand the importance of routine testing and to help address any barriers they may have to incorporating routine HIV testing in their respective health-care settings. One of the challenges identified was the submitting and understanding of the proper coding requirements for routine HIV testing. This coding guide was designed to help physicians and their staff navigate this often confusing process. The brochure is available as a downloadable PDF below.
Additionally, the AMA is exploring options to convert this Guide into a portable point-of-care pamphlet. Please visit this Web page in the future for updates.
This Guide is the result of efforts by the AMA, the AAHIVM, and several other national partners to help physicians understand the importance of routine testing and to help address any barriers they may have to incorporating routine HIV testing in their respective health-care settings. One of the challenges identified was the submitting and understanding of the proper coding requirements for routine HIV testing. This coding guide was designed to help physicians and their staff navigate this often confusing process. The brochure is available as a downloadable PDF below.
Additionally, the AMA is exploring options to convert this Guide into a portable point-of-care pamphlet. Please visit this Web page in the future for updates.
Medical specialists
Medical specialists
The medical treatment of infectious diseases falls into the medical field of Infectiology and in some cases the study of propagation pertains to the field of Epidemiology. Generally, infections are initially diagnosed by primary care physicians or internal medicine specialists. For example, an "uncomplicated" pneumonia will generally be treated by the internist or the pulmonologist (lung physician).The work of the infectiologist therefore entails working with both patients and general practitioners, as well as laboratory scientists, immunologists, bacteriologists and other specialists..
An infectious disease team may be alerted when:
The disease has not been definitively diagnosed after an initial workup
The patient is immunocompromised (for example, in AIDS or after chemotherapy);
The infectious agent is of an uncommon nature (e.g. tropical diseases);
The disease has not responded to first line antibiotics;
The disease might be dangerous to other patients, and the patient might have to be isolated
The medical treatment of infectious diseases falls into the medical field of Infectiology and in some cases the study of propagation pertains to the field of Epidemiology. Generally, infections are initially diagnosed by primary care physicians or internal medicine specialists. For example, an "uncomplicated" pneumonia will generally be treated by the internist or the pulmonologist (lung physician).The work of the infectiologist therefore entails working with both patients and general practitioners, as well as laboratory scientists, immunologists, bacteriologists and other specialists..
An infectious disease team may be alerted when:
The disease has not been definitively diagnosed after an initial workup
The patient is immunocompromised (for example, in AIDS or after chemotherapy);
The infectious agent is of an uncommon nature (e.g. tropical diseases);
The disease has not responded to first line antibiotics;
The disease might be dangerous to other patients, and the patient might have to be isolated
The study of infectious disease - History
The study of infectious disease
History
German postage stamps depicting four antique microscopes. Advancements in microscopy were essential to the early study of infectious diseases.Abū Alī ibn Sīnā (Avicenna) discovered the contagious nature of infectious diseases in the early 11th century. He introduced quarantine as a means of limiting the spread of contagious and infectious diseases in The Canon of Medicine, circa 1020.[20] He also stated that bodily secretion is contaminated by foul foreign earthly bodies before being infected, but he did not view them as primary causes of disease.[21]
When the Black Death bubonic plague reached al-Andalus in the 14th century, Ibn Khatima and Ibn al-Khatib hypothesized that infectious diseases are caused by "contagious entities" which enter the human body.[21] Such ideas became more popular in Europe during the renaissance, particularly through the writing of the Italian monk Girolamo Fracastoro.[22]
Anton van Leeuwenhoek (1632-1723) advanced the science of microscopy by being the first to observe microorganisms, allowing for easy visualization of bacteria.
Louis Pasteur proved beyond doubt that certain diseases are caused by infectious agents, and developed a vaccine for rabies.
Robert Koch, provided the study of infectious diseases with a scientific basis known as Koch's postulates.
Edward Jenner, Jonas Salk and Albert Sabin developed effective vaccines for smallpox and polio, which would later result in the eradication and near-eradication of these diseases, respectively.
Alexander Fleming discovered the world's first antibiotic Penicillin.
Gerhard Domagk developed Sulphonamides, the first broad spectrum synthetic antibacterial drugs.
History
German postage stamps depicting four antique microscopes. Advancements in microscopy were essential to the early study of infectious diseases.Abū Alī ibn Sīnā (Avicenna) discovered the contagious nature of infectious diseases in the early 11th century. He introduced quarantine as a means of limiting the spread of contagious and infectious diseases in The Canon of Medicine, circa 1020.[20] He also stated that bodily secretion is contaminated by foul foreign earthly bodies before being infected, but he did not view them as primary causes of disease.[21]
When the Black Death bubonic plague reached al-Andalus in the 14th century, Ibn Khatima and Ibn al-Khatib hypothesized that infectious diseases are caused by "contagious entities" which enter the human body.[21] Such ideas became more popular in Europe during the renaissance, particularly through the writing of the Italian monk Girolamo Fracastoro.[22]
Anton van Leeuwenhoek (1632-1723) advanced the science of microscopy by being the first to observe microorganisms, allowing for easy visualization of bacteria.
Louis Pasteur proved beyond doubt that certain diseases are caused by infectious agents, and developed a vaccine for rabies.
Robert Koch, provided the study of infectious diseases with a scientific basis known as Koch's postulates.
Edward Jenner, Jonas Salk and Albert Sabin developed effective vaccines for smallpox and polio, which would later result in the eradication and near-eradication of these diseases, respectively.
Alexander Fleming discovered the world's first antibiotic Penicillin.
Gerhard Domagk developed Sulphonamides, the first broad spectrum synthetic antibacterial drugs.
Emerging diseases and pandemics
Emerging diseases and pandemics
In most cases, microorganisms live in harmony with their hosts. Such is the case for many tropical viruses and the insects, monkeys, or other animals in which they have lived and reproduced. Because the microbes and their hosts have co-evolved, the hosts gradually become resistant to the microorganisms. When a microbe jumps from a long-time animal host to a human being, it may cease to be a harmless parasite and become pathogenic.[17]
With most new infectious diseases, some human action is involved, changing the environment so that an existing microbe can take up residence in a new niche. When that happens, a pathogen that had been confined to a remote habitat appears in a new or wider region, or a microbe that had infected only animals suddenly begins to cause human disease.
Several human activities have led to the emergence and spread of new diseases,[17] see also Globalization and Disease:
Encroachment on wildlife habitats. The construction of new villages and housing developments in rural areas brings people into contact with animals--and the microbes they harbor.
Changes in agriculture. The introduction of new crops attracts new crop pests and the microbes they carry to farming communities, exposing people to unfamiliar diseases.
The destruction of rain forests. As countries make use of their rain forests, by building roads through forests and clearing areas for settlement or commercial ventures, people encounter insects and other animals harboring previously unknown microorganisms.
Uncontrolled urbanization. The rapid growth of cities in many developing countries tends to concentrate large numbers of people into crowded areas with poor sanitation. These conditions foster transmission of contagious diseases.
Modern transport. Ships and other cargo carriers often harbor unintended "passengers", that can spread diseases to faraway destinations. While with international jet-airplane travel, people infected with a disease can carry it to distant lands, or home to their families, before their first symptoms appear.
Climate change. Global warming is expected to increase the potential geographic range and virulence of tropical diseases.[18] Climate change could cause a major increase in insect-borne diseases such as malaria throughout Europe, North America and North Asia.[19]
In most cases, microorganisms live in harmony with their hosts. Such is the case for many tropical viruses and the insects, monkeys, or other animals in which they have lived and reproduced. Because the microbes and their hosts have co-evolved, the hosts gradually become resistant to the microorganisms. When a microbe jumps from a long-time animal host to a human being, it may cease to be a harmless parasite and become pathogenic.[17]
With most new infectious diseases, some human action is involved, changing the environment so that an existing microbe can take up residence in a new niche. When that happens, a pathogen that had been confined to a remote habitat appears in a new or wider region, or a microbe that had infected only animals suddenly begins to cause human disease.
Several human activities have led to the emergence and spread of new diseases,[17] see also Globalization and Disease:
Encroachment on wildlife habitats. The construction of new villages and housing developments in rural areas brings people into contact with animals--and the microbes they harbor.
Changes in agriculture. The introduction of new crops attracts new crop pests and the microbes they carry to farming communities, exposing people to unfamiliar diseases.
The destruction of rain forests. As countries make use of their rain forests, by building roads through forests and clearing areas for settlement or commercial ventures, people encounter insects and other animals harboring previously unknown microorganisms.
Uncontrolled urbanization. The rapid growth of cities in many developing countries tends to concentrate large numbers of people into crowded areas with poor sanitation. These conditions foster transmission of contagious diseases.
Modern transport. Ships and other cargo carriers often harbor unintended "passengers", that can spread diseases to faraway destinations. While with international jet-airplane travel, people infected with a disease can carry it to distant lands, or home to their families, before their first symptoms appear.
Climate change. Global warming is expected to increase the potential geographic range and virulence of tropical diseases.[18] Climate change could cause a major increase in insect-borne diseases such as malaria throughout Europe, North America and North Asia.[19]
Historic pandemics
Historic pandemics
A young Bangladeshi girl infected with smallpox (1973). Thanks to the development of the smallpox vaccine, the disease was officially eradicated in 1979.A pandemic (or global epidemic) is a disease that affects people over an extensive geographical area.
Plague of Justinian, from 541 to 750, killed between 50 and 60% of Europe's population.[13]
The Black Death of 1347 to 1352 killed 25 million in Europe over 5 years (estimated to be between 25 and 50% of the populations of Europe, Asia, and Africa - the world population at the time was 500 million).
The introduction of smallpox, measles, and typhus to the areas of Central and South America by European explorers during the 15th and 16th centuries caused pandemics among the native inhabitants. Between 1518 and 1568 disease pandemics are said to have caused the population of Mexico to fall from 20 million to 3 million.[14]
The first European influenza epidemic occurred between 1556 and 1560, with an estimated mortality rate of 20%.[14]
Smallpox killed an estimated 60 million Europeans in the 18th century alone. Up to 30% of those infected, including 80% of the children under 5 years of age, died from the disease, and one third of the survivors went blind. [15]
The Influenza Pandemic of 1918 (or the Spanish Flu) killed 25-50 million people (about 2% of world population of 1.7 billion).[16] Today Influenza kills about 250,000 to 500,000 worldwide each year.
A young Bangladeshi girl infected with smallpox (1973). Thanks to the development of the smallpox vaccine, the disease was officially eradicated in 1979.A pandemic (or global epidemic) is a disease that affects people over an extensive geographical area.
Plague of Justinian, from 541 to 750, killed between 50 and 60% of Europe's population.[13]
The Black Death of 1347 to 1352 killed 25 million in Europe over 5 years (estimated to be between 25 and 50% of the populations of Europe, Asia, and Africa - the world population at the time was 500 million).
The introduction of smallpox, measles, and typhus to the areas of Central and South America by European explorers during the 15th and 16th centuries caused pandemics among the native inhabitants. Between 1518 and 1568 disease pandemics are said to have caused the population of Mexico to fall from 20 million to 3 million.[14]
The first European influenza epidemic occurred between 1556 and 1560, with an estimated mortality rate of 20%.[14]
Smallpox killed an estimated 60 million Europeans in the 18th century alone. Up to 30% of those infected, including 80% of the children under 5 years of age, died from the disease, and one third of the survivors went blind. [15]
The Influenza Pandemic of 1918 (or the Spanish Flu) killed 25-50 million people (about 2% of world population of 1.7 billion).[16] Today Influenza kills about 250,000 to 500,000 worldwide each year.
Mortality from infectious diseases
Mortality from infectious diseases
The World Health Organization collects information on global deaths by International Classification of Disease (ICD) code categories. The following table lists the top infectious disease killers which caused more than 100,000 deaths in 2002 (estimated). 1993 data is included for comparison.
Worldwide mortality due to infectious diseases[9] Rank Cause of death Deaths 2002 Percentage of
all deaths Deaths 1993 1993 Rank
N/A All infectious diseases 14.7 million 25.9% 16.4 million 32.2%
1 Lower respiratory infections[10] 3.9 million 6.9% 4.1 million 1
2 HIV/AIDS 2.8 million 4.9% 0.7 million 7
3 Diarrheal diseases[11] 1.8 million 3.2% 3.0 million 2
4 Tuberculosis (TB) 1.6 million 2.7% 2.7 million 3
5 Malaria 1.3 million 2.2% 2.0 million 4
6 Measles 0.6 million 1.1% 1.1 million 5
7 Pertussis 0.29 million 0.5% 0.36 million 7
8 Tetanus 0.21 million 0.4% 0.15 million 12
9 Meningitis 0.17 million 0.3% 0.25 million 8
10 Syphilis 0.16 million 0.3% 0.19 million 11
11 Hepatitis B 0.10 million 0.2% 0.93 million 6
12-17 Tropical diseases (6)[12] 0.13 million 0.2% 0.53 million 9, 10, 16-18
Note: Other causes of death include maternal and perinatal conditions (5.2%), nutritional deficiencies (0.9%),
noncommunicable conditions (58.8%), and injuries (9.1%).
The top three single agent/disease killers are HIV/AIDS, TB and malaria. While the number of deaths due to nearly every disease have decreased, deaths due to HIV/AIDS have increased fourfold. Childhood diseases include pertussis, poliomyelitis, diphtheria, measles and tetanus. Children also make up a large percentage of lower respiratory and diarrheal deaths.
The World Health Organization collects information on global deaths by International Classification of Disease (ICD) code categories. The following table lists the top infectious disease killers which caused more than 100,000 deaths in 2002 (estimated). 1993 data is included for comparison.
Worldwide mortality due to infectious diseases[9] Rank Cause of death Deaths 2002 Percentage of
all deaths Deaths 1993 1993 Rank
N/A All infectious diseases 14.7 million 25.9% 16.4 million 32.2%
1 Lower respiratory infections[10] 3.9 million 6.9% 4.1 million 1
2 HIV/AIDS 2.8 million 4.9% 0.7 million 7
3 Diarrheal diseases[11] 1.8 million 3.2% 3.0 million 2
4 Tuberculosis (TB) 1.6 million 2.7% 2.7 million 3
5 Malaria 1.3 million 2.2% 2.0 million 4
6 Measles 0.6 million 1.1% 1.1 million 5
7 Pertussis 0.29 million 0.5% 0.36 million 7
8 Tetanus 0.21 million 0.4% 0.15 million 12
9 Meningitis 0.17 million 0.3% 0.25 million 8
10 Syphilis 0.16 million 0.3% 0.19 million 11
11 Hepatitis B 0.10 million 0.2% 0.93 million 6
12-17 Tropical diseases (6)[12] 0.13 million 0.2% 0.53 million 9, 10, 16-18
Note: Other causes of death include maternal and perinatal conditions (5.2%), nutritional deficiencies (0.9%),
noncommunicable conditions (58.8%), and injuries (9.1%).
The top three single agent/disease killers are HIV/AIDS, TB and malaria. While the number of deaths due to nearly every disease have decreased, deaths due to HIV/AIDS have increased fourfold. Childhood diseases include pertussis, poliomyelitis, diphtheria, measles and tetanus. Children also make up a large percentage of lower respiratory and diarrheal deaths.
Clearance and immunity
Clearance and immunity
Mary Mallon (a.k.a Typhoid Mary) was an asymptomatic carrier of typhoid fever. Over the course of her career as a cook, she infected 53 people, three of whom died.Infection with most pathogens does not result in death of the host and the offending organism is ultimately cleared after the symptoms of the disease have waned.[4] This process requires immune mechanisms to kill or inactivate the inoculum of the pathogen. Specific acquired immunity against infectious diseases may be mediated by antibodies and/or T lymphocytes. Immunity mediated by these two factors may be manifested by:
a direct effect upon a pathogen, such as antibody-initiated complement-dependent bacteriolysis, opsonoization, phagocytosis and killing, as occurs for some bacteria,
neutralization of viruses so that these organisms cannot enter cells,
or by T lymphocytes which will kill a cell parasitized by a microorganism.
The immune response to a microorganism often causes symptoms such as a high fever and inflammation, and has the potential to be more devastating than direct damage caused by a microbe.
Resistance to infection (immunity) may be acquired following a disease, by asymptomatic carriage of the pathogen, by harboring an organism with a similar structure (crossreacting), or by vaccination. Knowledge of the protective antigens and specific acquired host immune factors is more complete for primary pathogens than for opportunistic pathogens.
Immune resistance to an infectious disease requires a critical level of either antigen-specific antibodies and/or T cells when the host encounters the pathogen. Some individuals develop natural serum antibodies to the surface polysaccharides of some agents although they have had little or no contact with the agent, these natural antibodies confer specific protection to adults and are passively transmitted to newborns.
Mary Mallon (a.k.a Typhoid Mary) was an asymptomatic carrier of typhoid fever. Over the course of her career as a cook, she infected 53 people, three of whom died.Infection with most pathogens does not result in death of the host and the offending organism is ultimately cleared after the symptoms of the disease have waned.[4] This process requires immune mechanisms to kill or inactivate the inoculum of the pathogen. Specific acquired immunity against infectious diseases may be mediated by antibodies and/or T lymphocytes. Immunity mediated by these two factors may be manifested by:
a direct effect upon a pathogen, such as antibody-initiated complement-dependent bacteriolysis, opsonoization, phagocytosis and killing, as occurs for some bacteria,
neutralization of viruses so that these organisms cannot enter cells,
or by T lymphocytes which will kill a cell parasitized by a microorganism.
The immune response to a microorganism often causes symptoms such as a high fever and inflammation, and has the potential to be more devastating than direct damage caused by a microbe.
Resistance to infection (immunity) may be acquired following a disease, by asymptomatic carriage of the pathogen, by harboring an organism with a similar structure (crossreacting), or by vaccination. Knowledge of the protective antigens and specific acquired host immune factors is more complete for primary pathogens than for opportunistic pathogens.
Immune resistance to an infectious disease requires a critical level of either antigen-specific antibodies and/or T cells when the host encounters the pathogen. Some individuals develop natural serum antibodies to the surface polysaccharides of some agents although they have had little or no contact with the agent, these natural antibodies confer specific protection to adults and are passively transmitted to newborns.
Molecular diagnostics
Molecular diagnostics
Technologies based upon the polymerase chain reaction (PCR) method will become nearly ubiquitous gold standards of diagnostics of the near future, for several reasons. First, the catalog of infectious agents has grown to the point that virtually all of the significant infectious agents of the human population have been identified. Second, an infectious agent must grow within the human body to cause disease; essentially it must amplify its own nucleic acids in order to cause a disease. This amplification of nucleic acid in infected tissue offers an opportunity to detect the infectious agent by using PCR. Third, the essential tools for directing PCR, primers, are derived from the genomes of infectious agents, and with time those genomes will be known, if they are not already.
Thus, the technological ability to detect any infectious agent rapidly and specifically are currently available. The only remaining blockades to the use of PCR as a standard tool of diagnosis are in its cost and application, neither of which is insurmountable. The diagnosis of a few diseases will not benefit from the development of PCR methods, such as some of the clostridial diseases (tetanus and botulism). These diseases are fundamentally biological poisonings by relatively small numbers of infectious bacteria that produce extremely potent neurotoxins. A significant proliferation of the infectious agent does not occur, this limits the ability of PCR to detect the presence of any bacteria.
Technologies based upon the polymerase chain reaction (PCR) method will become nearly ubiquitous gold standards of diagnostics of the near future, for several reasons. First, the catalog of infectious agents has grown to the point that virtually all of the significant infectious agents of the human population have been identified. Second, an infectious agent must grow within the human body to cause disease; essentially it must amplify its own nucleic acids in order to cause a disease. This amplification of nucleic acid in infected tissue offers an opportunity to detect the infectious agent by using PCR. Third, the essential tools for directing PCR, primers, are derived from the genomes of infectious agents, and with time those genomes will be known, if they are not already.
Thus, the technological ability to detect any infectious agent rapidly and specifically are currently available. The only remaining blockades to the use of PCR as a standard tool of diagnosis are in its cost and application, neither of which is insurmountable. The diagnosis of a few diseases will not benefit from the development of PCR methods, such as some of the clostridial diseases (tetanus and botulism). These diseases are fundamentally biological poisonings by relatively small numbers of infectious bacteria that produce extremely potent neurotoxins. A significant proliferation of the infectious agent does not occur, this limits the ability of PCR to detect the presence of any bacteria.
Biochemical tests
Biochemical tests
Biochemical tests used in the identification of infectious agents include the detection of metabolic or enzymatic products characteristic of a particular infectious agent. Since bacteria ferment carbohydrates in patterns characteristic of their genus and species, the detection of fermentation products is commonly used in bacterial identification. Acids, alcohols and gases are usually detected in these tests when bacteria are grown in selective liquid or solid media.
The isolation of enzymes from infected tissue can also provide the basis of a biochemical diagnosis of an infectious disease. For example, humans can make neither RNA replicases nor reverse transcriptase, and the presence of these enzymes are characteristic of specific types of viral infections. The ability of the viral protein hemagglutinin to bind red blood cells together into a detectable matrix may also be characterized as a biochemical test for viral infection, although strictly speaking hemagglutinin is not an enzyme and has no metabolic function.
Serological methods are highly sensitive, specific and often extremely rapid tests used to identify microorganisms. These tests are based upon the ability of an antibody to bind specifically to an antigen. The antigen, usually a protein or carbohydrate made by an infectious agent, is bound by the antibody. This binding then sets off a chain of events that can be visibly obvious in various ways, dependent upon the test. For example, "Strep throat" is often diagnosed within minutes, and is based on the appearance of antigens made by the causative agent, S. pyogenes, that is retrieved from a patients throat with a cotton swab. Serological tests, if available, are usually the preferred route of identification, however the tests are costly to develop and the reagents used in the test often require refrigeration. Some serological methods are extremely costly, although when commonly used, such as with the "strep test", they can be inexpensive.
Biochemical tests used in the identification of infectious agents include the detection of metabolic or enzymatic products characteristic of a particular infectious agent. Since bacteria ferment carbohydrates in patterns characteristic of their genus and species, the detection of fermentation products is commonly used in bacterial identification. Acids, alcohols and gases are usually detected in these tests when bacteria are grown in selective liquid or solid media.
The isolation of enzymes from infected tissue can also provide the basis of a biochemical diagnosis of an infectious disease. For example, humans can make neither RNA replicases nor reverse transcriptase, and the presence of these enzymes are characteristic of specific types of viral infections. The ability of the viral protein hemagglutinin to bind red blood cells together into a detectable matrix may also be characterized as a biochemical test for viral infection, although strictly speaking hemagglutinin is not an enzyme and has no metabolic function.
Serological methods are highly sensitive, specific and often extremely rapid tests used to identify microorganisms. These tests are based upon the ability of an antibody to bind specifically to an antigen. The antigen, usually a protein or carbohydrate made by an infectious agent, is bound by the antibody. This binding then sets off a chain of events that can be visibly obvious in various ways, dependent upon the test. For example, "Strep throat" is often diagnosed within minutes, and is based on the appearance of antigens made by the causative agent, S. pyogenes, that is retrieved from a patients throat with a cotton swab. Serological tests, if available, are usually the preferred route of identification, however the tests are costly to develop and the reagents used in the test often require refrigeration. Some serological methods are extremely costly, although when commonly used, such as with the "strep test", they can be inexpensive.
Microscopy
Microscopy
Another principle tool in the diagnosis of infectious disease is microscopy. Virtually all of the culture techniques discussed above rely, at some point, on microscopic examination for definitive identification of the infectious agent. Microscopy may be carried out with simple instruments, such as the compound light microscope, or with instruments as complex as an electron microscope. Samples obtained from patients may be viewed directly under the light microscope, and can often rapidly lead to identification. Microscopy is often also used in conjunction with biochemical staining techniques, and can be made exquisitely specific when used in combination with antibody based techniques. For example, the use of antibodies made artificially fluorescent (fluorescently labeled antibodies) can be directed to bind to and identify a specific antigens present on a pathogen. A fluorescence microscope is then used to detect fluorescently labeled antibodies bound to internalized antigens within clinical samples or cultured cells. This technique is especially useful in the diagnosis of viral diseases, where the light microscope is incapable of identifying a virus directly.
Other microscopic procedures may also aid in identifying infectious agents. Almost all cells readily stain with a number of basic dyes due to the electrostatic attraction between negatively charged cellular molecules and the positive charge on the dye. A cell is normally transparent under a microscope, and using a stain increases the contrast of a cell with its background. Staining a cell with a dye such as Giemsa stain or crystal violet allows a microscopist to describe its size, shape, internal and external components and its associations with other cells. The response of bacteria to different staining procedures is used in the taxonomic classification of microbes as well. Two methods, the Gram stain and the acid-fast stain, are the standard approaches used to classify bacteria and to diagnosis of disease. The Gram stain identifies the bacterial groups Firmicutes and Actinobacteria, both of which contain many significant human pathogens. The acid-fast staining procedure identifies the Actinobacterial genera Mycobacterium and Nocardia.
Another principle tool in the diagnosis of infectious disease is microscopy. Virtually all of the culture techniques discussed above rely, at some point, on microscopic examination for definitive identification of the infectious agent. Microscopy may be carried out with simple instruments, such as the compound light microscope, or with instruments as complex as an electron microscope. Samples obtained from patients may be viewed directly under the light microscope, and can often rapidly lead to identification. Microscopy is often also used in conjunction with biochemical staining techniques, and can be made exquisitely specific when used in combination with antibody based techniques. For example, the use of antibodies made artificially fluorescent (fluorescently labeled antibodies) can be directed to bind to and identify a specific antigens present on a pathogen. A fluorescence microscope is then used to detect fluorescently labeled antibodies bound to internalized antigens within clinical samples or cultured cells. This technique is especially useful in the diagnosis of viral diseases, where the light microscope is incapable of identifying a virus directly.
Other microscopic procedures may also aid in identifying infectious agents. Almost all cells readily stain with a number of basic dyes due to the electrostatic attraction between negatively charged cellular molecules and the positive charge on the dye. A cell is normally transparent under a microscope, and using a stain increases the contrast of a cell with its background. Staining a cell with a dye such as Giemsa stain or crystal violet allows a microscopist to describe its size, shape, internal and external components and its associations with other cells. The response of bacteria to different staining procedures is used in the taxonomic classification of microbes as well. Two methods, the Gram stain and the acid-fast stain, are the standard approaches used to classify bacteria and to diagnosis of disease. The Gram stain identifies the bacterial groups Firmicutes and Actinobacteria, both of which contain many significant human pathogens. The acid-fast staining procedure identifies the Actinobacterial genera Mycobacterium and Nocardia.
Methods of diagnosis - Microbial culture
Methods of diagnosis
Diagnosis of infectious disease is nearly always initiated by medical history and physical examination. More detailed identification techniques involve the culture of infectious agents isolated from a patient. Culture allows identification of infectious organisms by examining their microscopic features, by detecting the presence of substances produced by pathogens, and by directly identifying an organism by its genotype. Other techniques (such as X-rays, CAT scans, PET scans or NMR) are used to produce images of internal abnormalities resulting from the growth of an infectious agent. The images are useful in detection of, for example, a bone abscess or a spongiform encephalopathy produced by a prion.
Microbial culture
Four nutrient agar plates growing colonies of common Gram negative bacteria.Microbiological culture is a principal tool used to diagnose infectious disease. In a microbial culture, a growth medium is provided for a specific agent. A sample taken from potentially diseased tissue or fluid is then tested for the presence of an infectious agent able to grow within that medium. Most pathogenic bacteria are easily grown on nutrient agar, a form of solid medium that supplies carbohydrates and proteins necessary for growth of a bacterium, along with copious amounts of water. A single bacterium will grow into a visible mound on the surface of the plate called a colony, which may be separated from other colonies or melded together into a "lawn". The size, color, shape and form of a colony is characteristic of the bacterial species, its specific genetic makeup (its strain), and the environment which supports its growth. Other ingredients are often added to the plate to aid in identification. Plates may contain substances that permit the growth of some bacteria and not others, or that change color in response to certain bacteria and not others. Bacteriological plates such as these are commonly used in the clinical identification of infectious bacteria. Microbial culture may also be used in the identification of viruses: the medium in this case being cells grown in culture that the virus can infect, and then alter or kill. In the case of viral identification, a region of dead cells results from viral growth, and is called a "plaque". Eukaryotic parasites may also be grown in culture as a means of identifying a particular agent.
In the absence of suitable plate culture techniques, some microbes require culture within live animals. Bacteria such as Mycobacterium leprae and T. pallidum can be grown in animals, although serological and microscopic techniques make the use of live animals unnecessary. Viruses are also usually identified using alternatives to growth in culture or animals. Some viruses may be grown in embryonated eggs. Another useful identification method is Xenodiagnosis, or the use of a vector to support the growth of an infectious agent. Chaga's disease is the most significant example, because it is difficult to directly demonstrate the presence of the causative agent, Trypanosoma cruzi in a patient, which therefore makes it difficult to definitively make a diagnosis. In this case, xenodiagnosis involves the use of the vector of the Chaga's agent T. cruzi, an uninfected triatomine bug (subfamily Triatominae), which takes a blood meal from a person suspected of having been infected. The bug is later inspected for growth of T. cruzi within its gut.
Diagnosis of infectious disease is nearly always initiated by medical history and physical examination. More detailed identification techniques involve the culture of infectious agents isolated from a patient. Culture allows identification of infectious organisms by examining their microscopic features, by detecting the presence of substances produced by pathogens, and by directly identifying an organism by its genotype. Other techniques (such as X-rays, CAT scans, PET scans or NMR) are used to produce images of internal abnormalities resulting from the growth of an infectious agent. The images are useful in detection of, for example, a bone abscess or a spongiform encephalopathy produced by a prion.
Microbial culture
Four nutrient agar plates growing colonies of common Gram negative bacteria.Microbiological culture is a principal tool used to diagnose infectious disease. In a microbial culture, a growth medium is provided for a specific agent. A sample taken from potentially diseased tissue or fluid is then tested for the presence of an infectious agent able to grow within that medium. Most pathogenic bacteria are easily grown on nutrient agar, a form of solid medium that supplies carbohydrates and proteins necessary for growth of a bacterium, along with copious amounts of water. A single bacterium will grow into a visible mound on the surface of the plate called a colony, which may be separated from other colonies or melded together into a "lawn". The size, color, shape and form of a colony is characteristic of the bacterial species, its specific genetic makeup (its strain), and the environment which supports its growth. Other ingredients are often added to the plate to aid in identification. Plates may contain substances that permit the growth of some bacteria and not others, or that change color in response to certain bacteria and not others. Bacteriological plates such as these are commonly used in the clinical identification of infectious bacteria. Microbial culture may also be used in the identification of viruses: the medium in this case being cells grown in culture that the virus can infect, and then alter or kill. In the case of viral identification, a region of dead cells results from viral growth, and is called a "plaque". Eukaryotic parasites may also be grown in culture as a means of identifying a particular agent.
In the absence of suitable plate culture techniques, some microbes require culture within live animals. Bacteria such as Mycobacterium leprae and T. pallidum can be grown in animals, although serological and microscopic techniques make the use of live animals unnecessary. Viruses are also usually identified using alternatives to growth in culture or animals. Some viruses may be grown in embryonated eggs. Another useful identification method is Xenodiagnosis, or the use of a vector to support the growth of an infectious agent. Chaga's disease is the most significant example, because it is difficult to directly demonstrate the presence of the causative agent, Trypanosoma cruzi in a patient, which therefore makes it difficult to definitively make a diagnosis. In this case, xenodiagnosis involves the use of the vector of the Chaga's agent T. cruzi, an uninfected triatomine bug (subfamily Triatominae), which takes a blood meal from a person suspected of having been infected. The bug is later inspected for growth of T. cruzi within its gut.
Diagnosis and therapy
Diagnosis of infectious disease sometimes involves identifying an infectious agent either directly or indirectly. In practice most minor infectious diseases such as warts, cutaneous abscesses, respiratory system infections and diarrheal diseases are diagnosed by their clinical presentation. Conclusions about the cause of the disease are based upon the likelihood that a patient came in contact with a particular agent, the presence of a microbe in a community, and other epidemiological considerations. Given sufficient effort, all known infectious agents can be specifically identified. The benefits of identification, however, are often greatly outweighed by the cost, as often there is no specific treatment, the cause is obvious, or the outcome of an infection is benign.
Specific identification of an infectious agent is usually only determined when such identification can aid in the treatment or prevention of the disease, or to advance knowledge of the course of an illness prior to the development of effective therapeutic or preventative measures. For example, in the early 1980s, prior to the appearance of AZT for the treatment of AIDS, the course of the disease was closely followed by monitoring the composition of patient blood samples, even though the outcome would not offer the patient any further treatment options. In part, these studies on the appearance of HIV in specific communities permitted the advancement of hypotheses as to the route of transmission of the virus. By understanding how the disease was transmitted, resources could be targeted to the communities at greatest risk in campaigns aimed at reducing the number of new infections. The specific serological diagnostic identification, and later genotypic or molecular identification, of HIV also enabled the development of hypotheses as to the temporal and geographical origins of the virus, as well as a myriad of other hypothesis. The development of molecular diagnostic tools have enabled physicians and researchers to monitor the efficacy of treatment with anti-retroviral drugs. Molecular diagnostics are now commonly used to identify HIV in healthy people long before the onset of illness and have been used to demonstrate the existence of people who are genetically resistant to HIV infection. Thus, while there still is no cure for AIDS, there is great therapeutic and predictive benefit to identifying the virus and monitoring the virus levels within the blood of infected individuals, both for the patient and for the community at large.
Specific identification of an infectious agent is usually only determined when such identification can aid in the treatment or prevention of the disease, or to advance knowledge of the course of an illness prior to the development of effective therapeutic or preventative measures. For example, in the early 1980s, prior to the appearance of AZT for the treatment of AIDS, the course of the disease was closely followed by monitoring the composition of patient blood samples, even though the outcome would not offer the patient any further treatment options. In part, these studies on the appearance of HIV in specific communities permitted the advancement of hypotheses as to the route of transmission of the virus. By understanding how the disease was transmitted, resources could be targeted to the communities at greatest risk in campaigns aimed at reducing the number of new infections. The specific serological diagnostic identification, and later genotypic or molecular identification, of HIV also enabled the development of hypotheses as to the temporal and geographical origins of the virus, as well as a myriad of other hypothesis. The development of molecular diagnostic tools have enabled physicians and researchers to monitor the efficacy of treatment with anti-retroviral drugs. Molecular diagnostics are now commonly used to identify HIV in healthy people long before the onset of illness and have been used to demonstrate the existence of people who are genetically resistant to HIV infection. Thus, while there still is no cure for AIDS, there is great therapeutic and predictive benefit to identifying the virus and monitoring the virus levels within the blood of infected individuals, both for the patient and for the community at large.
Preventing transmission
One of the ways to prevent or slow down the transmission of infectious diseases is to recognize the different characteristics of various diseases. [6] Some critical disease characteristics that should be evaluated include virulence, distance traveled by victims, and level of contagiousness. The human strains of Ebola virus, for example, incapacitate its victims extremely quickly and kills them soon after. As a result, the victims of this disease do not have the opportunity to travel very far from the initial infection zone. [7] Also, this virus must spread through skin lesions or permeable membranes such as the eye. Thus, the initial stage of Ebola is not very contagious since its victims experience only internal hemorrhaging. As a result of the above features, the spread of Ebola is very rapid and usually stays within a relatively confined geographical area. In contrast, Human Immunodeficiency Virus (HIV) kills its victims very slowly by attacking their immune system. [6] As a result, a lot of its victims transmit the virus to many others before even realizing that they are carrying the disease. Also, the relatively low virulence allows its victims to travel long distances, increasing the likelihood of an epidemic.
Another effective way to decrease the transmission rate of infectious diseases is to recognize the effects of small-world networks. [6] In epidemics, there are often extensive interactions within hubs or groups of infected individuals and other interactions within discrete hubs of susceptible individuals. Despite the low interaction between discrete hubs, the disease can jump to and spread in a susceptible hub via a single or few interactions with an infected hub. Thus, infection rates in small-world networks can be reduced somewhat if interactions between individuals within infected hubs are eliminated (Figure 1). However, infection rates can be drastically reduced if the main focus is on the prevention of transmission jumps between hubs. The use of needle exchange programs in areas with a high density of drug users with HIV is an example of the successful implementation of this treatment method. [6] Another example is the use of ring culling or vaccination of potentially susceptible livestock in adjacent farms to prevent the spread of the foot-and-mouth virus in 2001. [8]
General methods to prevent transmission of pathogens may include disinfection and pest control.
Another effective way to decrease the transmission rate of infectious diseases is to recognize the effects of small-world networks. [6] In epidemics, there are often extensive interactions within hubs or groups of infected individuals and other interactions within discrete hubs of susceptible individuals. Despite the low interaction between discrete hubs, the disease can jump to and spread in a susceptible hub via a single or few interactions with an infected hub. Thus, infection rates in small-world networks can be reduced somewhat if interactions between individuals within infected hubs are eliminated (Figure 1). However, infection rates can be drastically reduced if the main focus is on the prevention of transmission jumps between hubs. The use of needle exchange programs in areas with a high density of drug users with HIV is an example of the successful implementation of this treatment method. [6] Another example is the use of ring culling or vaccination of potentially susceptible livestock in adjacent farms to prevent the spread of the foot-and-mouth virus in 2001. [8]
General methods to prevent transmission of pathogens may include disinfection and pest control.
Transmission
An infectious disease is transmitted from some source. Defining the means of transmission plays an important part in understanding the biology of an infectious agent, and in addressing the disease it causes. Transmission may occur through several different mechanisms. Respiratory diseases and meningitis are commonly acquired by contact with aerosolized droplets, spread by sneezing, coughing, talking, kissing or even singing. Gastrointestinal diseases are often acquired by ingesting contaminated food and water. Sexually transmitted diseases are acquired through contact with bodily fluids, generally as a result of sexual activity. Some infectious agents may be spread as a result of contact with a contaminated, inanimate object (known as a fomite), such as a coin passed from one person to another, while other diseases penetrate the skin directly.[5]
Transmission of infectious diseases may also involve a "vector". Vectors may be mechanical or biological. A mechanical vector picks up an infectious agent on the outside of its body and transmits it in a passive manner. An example of a mechanical vector is a housefly, which lands on cow dung, contaminating its appendages with bacteria from the feces, and then lands on food prior to consumption. The pathogen never enters the body of the fly.
Culex mosquitos (Culex quinquefasciatus shown) are biological vectors that transmit West Nile Virus.In contrast, biological vectors harbor pathogens within their bodies and deliver pathogens to new hosts in an active manner, usually a bite. Biological vectors are often responsible for serious blood-borne diseases, such as malaria, viral encephalitis, Chagas disease, Lyme disease and African sleeping sickness. Biological vectors are usually, though not exclusively, arthropods, such as mosquitoes, ticks, fleas and lice. Vectors are often required in the life cycle of a pathogen. A common strategy, used to control vector borne infectious diseases, is to interrupt the life cycle of a pathogen, by killing the vector.
The relationship between virulence and transmission is complex, and has important consequences for the long term evolution of a pathogen. Since it takes many generations for a microbe and a new host species to co-evolve, an emerging pathogen may hit its earliest victims especially hard. It is usually in the first wave of a new disease that death rates are highest. If a disease is rapidly fatal, the host may die before the microbe can get passed along to another host. However, this cost may be overwhelmed by the short term benefit of higher infectiousness if transmission is linked to virulence, as it is for instance in the case of cholera (the explosive diarrhea aids the bacterium in finding new hosts) or many respiratory infections (sneezing and coughing create infectious aerosols).
Transmission of infectious diseases may also involve a "vector". Vectors may be mechanical or biological. A mechanical vector picks up an infectious agent on the outside of its body and transmits it in a passive manner. An example of a mechanical vector is a housefly, which lands on cow dung, contaminating its appendages with bacteria from the feces, and then lands on food prior to consumption. The pathogen never enters the body of the fly.
Culex mosquitos (Culex quinquefasciatus shown) are biological vectors that transmit West Nile Virus.In contrast, biological vectors harbor pathogens within their bodies and deliver pathogens to new hosts in an active manner, usually a bite. Biological vectors are often responsible for serious blood-borne diseases, such as malaria, viral encephalitis, Chagas disease, Lyme disease and African sleeping sickness. Biological vectors are usually, though not exclusively, arthropods, such as mosquitoes, ticks, fleas and lice. Vectors are often required in the life cycle of a pathogen. A common strategy, used to control vector borne infectious diseases, is to interrupt the life cycle of a pathogen, by killing the vector.
The relationship between virulence and transmission is complex, and has important consequences for the long term evolution of a pathogen. Since it takes many generations for a microbe and a new host species to co-evolve, an emerging pathogen may hit its earliest victims especially hard. It is usually in the first wave of a new disease that death rates are highest. If a disease is rapidly fatal, the host may die before the microbe can get passed along to another host. However, this cost may be overwhelmed by the short term benefit of higher infectiousness if transmission is linked to virulence, as it is for instance in the case of cholera (the explosive diarrhea aids the bacterium in finding new hosts) or many respiratory infections (sneezing and coughing create infectious aerosols).
Classification
Among the almost infinite varieties of microorganisms, relatively few cause disease in otherwise healthy individuals.[4] Infectious disease results from the interplay between those few pathogens and the defenses of the hosts they infect. The appearance and severity of disease resulting from any pathogen depends upon the ability of that pathogen to damage the host as well as the ability of the host to resist the pathogen. Infectious microorganisms, or microbes, are therefore classified as either primary pathogens or as opportunistic pathogens according to the status of host defenses.
Primary pathogens cause disease as a result of their presence or activity within the normal, healthy host, and their intrinsic virulence (the severity of the disease they cause) is, in part, a necessary consequence of their need to reproduce and spread. Many of the most common primary pathogens of humans only infect humans, however many serious diseases are caused by organisms acquired from the environment or which infect non-human hosts.
Organisms which cause an infectious disease in a host with depressed resistance are classified as opportunistic pathogens. Opportunistic disease may be caused by microbes that are ordinarily in contact with the host, such as pathogenic bacteria or fungi in the gastrointestinal or the upper respiratory tract, and they may also result from (otherwise innocuous) microbes acquired from other hosts (as in Clostridium difficile colitis) or from the environment as a result of traumatic introduction (as in surgical wound infections or compound fractures). An opportunistic disease requires impairment of host defenses, which may occur as a result of genetic defects (such as Chronic granulomatous disease), exposure to antimicrobial drugs or immunosuppressive chemicals (as might occur following poisoning or cancer chemotherapy), exposure to ionizing radiation, or as a result of an infectious disease with immunosuppressive activity (such as with measles, malaria or HIV disease). Primary pathogens may also cause more severe disease in a host with depressed resistance than would normally occur in an immunosufficient host.
One way of proving that a given disease is "infectious", is to satisfy Koch's postulates (first proposed by Robert Koch), which demands that the infectious agent be identified only in patients and not in healthy controls, and that patients who contract the agent also develop the disease. These postulates were first used in the discovery that Mycobacteria species cause tuberculosis. Koch's postulates cannot be met ethically for many human diseases because they require experimental infection of a healthy individual with a pathogen produced as a pure culture. Often, even diseases that are quite clearly infectious do not meet the infectious criteria. For example, Treponema pallidum, the causative spirochete of syphilis, cannot be cultured in vitro - however the organism can be cultured in rabbit testes. It is less clear that a pure culture comes from an animal source serving as host than it is when derived from microbes derived from plate culture. Epidemiology is another important tool used to study disease in a population. For infectious diseases it helps to determine if a disease outbreak is sporadic (occasional occurrence), endemic (regular cases often occurring in a region), epidemic (an unusually high number of cases in a region), or pandemic (a global epidemic).
Primary pathogens cause disease as a result of their presence or activity within the normal, healthy host, and their intrinsic virulence (the severity of the disease they cause) is, in part, a necessary consequence of their need to reproduce and spread. Many of the most common primary pathogens of humans only infect humans, however many serious diseases are caused by organisms acquired from the environment or which infect non-human hosts.
Organisms which cause an infectious disease in a host with depressed resistance are classified as opportunistic pathogens. Opportunistic disease may be caused by microbes that are ordinarily in contact with the host, such as pathogenic bacteria or fungi in the gastrointestinal or the upper respiratory tract, and they may also result from (otherwise innocuous) microbes acquired from other hosts (as in Clostridium difficile colitis) or from the environment as a result of traumatic introduction (as in surgical wound infections or compound fractures). An opportunistic disease requires impairment of host defenses, which may occur as a result of genetic defects (such as Chronic granulomatous disease), exposure to antimicrobial drugs or immunosuppressive chemicals (as might occur following poisoning or cancer chemotherapy), exposure to ionizing radiation, or as a result of an infectious disease with immunosuppressive activity (such as with measles, malaria or HIV disease). Primary pathogens may also cause more severe disease in a host with depressed resistance than would normally occur in an immunosufficient host.
One way of proving that a given disease is "infectious", is to satisfy Koch's postulates (first proposed by Robert Koch), which demands that the infectious agent be identified only in patients and not in healthy controls, and that patients who contract the agent also develop the disease. These postulates were first used in the discovery that Mycobacteria species cause tuberculosis. Koch's postulates cannot be met ethically for many human diseases because they require experimental infection of a healthy individual with a pathogen produced as a pure culture. Often, even diseases that are quite clearly infectious do not meet the infectious criteria. For example, Treponema pallidum, the causative spirochete of syphilis, cannot be cultured in vitro - however the organism can be cultured in rabbit testes. It is less clear that a pure culture comes from an animal source serving as host than it is when derived from microbes derived from plate culture. Epidemiology is another important tool used to study disease in a population. For infectious diseases it helps to determine if a disease outbreak is sporadic (occasional occurrence), endemic (regular cases often occurring in a region), epidemic (an unusually high number of cases in a region), or pandemic (a global epidemic).
An infectious disease is a clinically evident disease
An infectious disease is a clinically evident disease resulting from the presence of pathogenic microbial agents, including pathogenic viruses, pathogenic bacteria, fungi, protozoa, multicellular parasites, and aberrant proteins known as prions. These pathogens are able to cause disease in animals and/or plants.
Infectious pathologies are usually qualified as contagious diseases (also called communicable diseases) due to their potentiality of transmission from one person or species to another.[1] Transmission of an infectious disease may occur through one or more of diverse pathways including physical contact with infected individuals. These infecting agents may also be transmitted through liquids, food, body fluids, contaminated objects, airborne inhalation, or through vector-borne spread.[2]
The term infectivity describes the ability of an organism to enter, survive and multiply in the host, while the infectiousness of a disease indicates the comparative ease with which the disease is transmitted to other hosts.[3] An infection however, is not synonymous with an infectious disease, as an infection may not cause important clinical symptoms or impair host function
Infectious pathologies are usually qualified as contagious diseases (also called communicable diseases) due to their potentiality of transmission from one person or species to another.[1] Transmission of an infectious disease may occur through one or more of diverse pathways including physical contact with infected individuals. These infecting agents may also be transmitted through liquids, food, body fluids, contaminated objects, airborne inhalation, or through vector-borne spread.[2]
The term infectivity describes the ability of an organism to enter, survive and multiply in the host, while the infectiousness of a disease indicates the comparative ease with which the disease is transmitted to other hosts.[3] An infection however, is not synonymous with an infectious disease, as an infection may not cause important clinical symptoms or impair host function
Infectious Disease After Natural Disasters
Infectious Disease After Natural Disasters
Infectious Disease After Natural Disasters
Infectious Disease After Natural Disasters
Tuesday, December 25, 2007
Infectious Disease Clinic
Virtual tour for you and your child.
The Infectious Disease Health Care Unit and the Infectious Disease Clinic of the CHU Sainte-Justine are part of the pediatric program. The program's team is made up of multidisciplinary professionals who offer their services to an inpatient and outpatient clientele.
Patients admitted to the hospital unit come from the Emergency Ward, Outpatient Clinics, day centers or from an interinstitutional transfer. Patients monitored in the Infectious Disease Clinic are generally referred by a health care professional.
The program's philosophy focuses on the patient and the patient's family. Each member of the team contributes toward creating a warm and welcoming atmosphere where differences are respected.
The Infectious Disease Health Care Unit and the Infectious Disease Clinic of the CHU Sainte-Justine are part of the pediatric program. The program's team is made up of multidisciplinary professionals who offer their services to an inpatient and outpatient clientele.
Patients admitted to the hospital unit come from the Emergency Ward, Outpatient Clinics, day centers or from an interinstitutional transfer. Patients monitored in the Infectious Disease Clinic are generally referred by a health care professional.
The program's philosophy focuses on the patient and the patient's family. Each member of the team contributes toward creating a warm and welcoming atmosphere where differences are respected.
Sunday, March 11, 2007
Get Smart: Know When Antibiotics Work on the Farm: Educational Activities to Promote Appropriate Use of Antimicrobial Agents in Animals
1) Distribute current practices and educational materials
2) Fund sites and provide technical assistance to develop, implement, and evaluate local campaigns
3) Support development and testing of veterinary medical curricula for students
4) Fund a national advertising campaign promoting the appropriate use of antibiotics
5) Develop an efficient and accurate means of measuring antimicrobial use in veterinary medicine and agriculture
Appropriate Use of Antimicrobial Agents: Course Materials for Veterinary Students and Veterinary Continuing Education
This interactive web-based program combines aspects of microbiology, pharmacology, infectious disease and public health to promote appropriate use of antimicrobial agents by veterinarians. Working in partnership with human health professionals, food animal producers, animal owners, and the general public, the appropriate use of antimicrobial agents by veterinarians can help to mitigate further development and spread of resistance in human, animal, and zoonotic pathogens and commensal bacteria. The program consists of two parts:
blue arrow bullet A Background module that provides an introduction to the global, ecological nature of the antimicrobial resistance problem.
blue arrow bullet Species-specific modules that contain interactive case scenarios aimed at providing practical, clinical applications for the appropriate use guidelines as set forth in the WHO Global Principles for the Containment of Antimicrobial Resistance in Animals Intended for Food.
Specific topics addressed in the program include:
blue arrow bullet Mechanisms of resistance
blue arrow bullet Diagnostic tools and tests
blue arrow bullet Guidelines for empirical treatment
blue arrow bullet Client education
blue arrow bullet Alternatives to antibiotics
blue arrow bullet Resistance in animals secondary to use of antimicrobial agents
blue arrow bullet Public health risks of use of antimicrobial agents in food animals and in companion animals and the connection to antimicrobial resistant infections in people
State Demonstration Project: Collaborations Between State Public Health and Veterinary Diagnostic Laboratories
blue arrow bullet To foster collaborations on antimicrobial resistance between state public health laboratories and state agriculture (veterinary diagnostic) laboratories.
blue arrow bullet To establish local surveillance of antimicrobial resistance among enteric bacteria from humans and animals.
blue arrow bullet To develop community-based programs on appropriate use of antimicrobials in animals.
blue arrow bullet CDC is currently supporting a project between Michigan Department of Community Health and the Diagnostic Center for Animal Population Health at Michigan State University.
Get Smart on the Farm BarnFor more information contact GET SMART: Know When Antibiotics Work on the Farm :
Bernadette Hartman, DVM
Centers for Disease Control and Prevention
National Antimicrobial Resistance Monitoring System
1600 Clifton Road, MS-D63
Atlanta, GA 30333
Phone: 404-639-3399
Fax: 404-639-3535
Email: getsmartfarm@cdc.gov
For more information on the overall Get Smart program, please click HERE.
2) Fund sites and provide technical assistance to develop, implement, and evaluate local campaigns
3) Support development and testing of veterinary medical curricula for students
4) Fund a national advertising campaign promoting the appropriate use of antibiotics
5) Develop an efficient and accurate means of measuring antimicrobial use in veterinary medicine and agriculture
Appropriate Use of Antimicrobial Agents: Course Materials for Veterinary Students and Veterinary Continuing Education
This interactive web-based program combines aspects of microbiology, pharmacology, infectious disease and public health to promote appropriate use of antimicrobial agents by veterinarians. Working in partnership with human health professionals, food animal producers, animal owners, and the general public, the appropriate use of antimicrobial agents by veterinarians can help to mitigate further development and spread of resistance in human, animal, and zoonotic pathogens and commensal bacteria. The program consists of two parts:
blue arrow bullet A Background module that provides an introduction to the global, ecological nature of the antimicrobial resistance problem.
blue arrow bullet Species-specific modules that contain interactive case scenarios aimed at providing practical, clinical applications for the appropriate use guidelines as set forth in the WHO Global Principles for the Containment of Antimicrobial Resistance in Animals Intended for Food.
Specific topics addressed in the program include:
blue arrow bullet Mechanisms of resistance
blue arrow bullet Diagnostic tools and tests
blue arrow bullet Guidelines for empirical treatment
blue arrow bullet Client education
blue arrow bullet Alternatives to antibiotics
blue arrow bullet Resistance in animals secondary to use of antimicrobial agents
blue arrow bullet Public health risks of use of antimicrobial agents in food animals and in companion animals and the connection to antimicrobial resistant infections in people
State Demonstration Project: Collaborations Between State Public Health and Veterinary Diagnostic Laboratories
blue arrow bullet To foster collaborations on antimicrobial resistance between state public health laboratories and state agriculture (veterinary diagnostic) laboratories.
blue arrow bullet To establish local surveillance of antimicrobial resistance among enteric bacteria from humans and animals.
blue arrow bullet To develop community-based programs on appropriate use of antimicrobials in animals.
blue arrow bullet CDC is currently supporting a project between Michigan Department of Community Health and the Diagnostic Center for Animal Population Health at Michigan State University.
Get Smart on the Farm BarnFor more information contact GET SMART: Know When Antibiotics Work on the Farm :
Bernadette Hartman, DVM
Centers for Disease Control and Prevention
National Antimicrobial Resistance Monitoring System
1600 Clifton Road, MS-D63
Atlanta, GA 30333
Phone: 404-639-3399
Fax: 404-639-3535
Email: getsmartfarm@cdc.gov
For more information on the overall Get Smart program, please click HERE.
Friday, June 02, 2006
Similarity between Human and Chicken Escherichia coli Isolates in Relation to Ciprofloxacin Resistance Status
Background. The food supply is suspected to be a source of fluoroquinolone-resistant
Methods. We performed a molecular-epidemiological comparison, in Barcelona, Spain (1996
Results. When analyzed by phylogenetic distribution, virulence profiles, and O antigens, resistant human isolates were distinct from susceptible human isolates but were largely indistinguishable from chicken isolates, whereas resistant and susceptible chicken isolates were similar. Susceptible human isolates contained more virulence-associated genes and more frequently expressed virulence-associated O antigens than did resistant human or any chicken isolates. Certain resistant human isolates closely resembled chicken isolates by RAPD and PFGE analysis.
Conclusions. Ciprofloxacin-resistant
Wednesday, April 19, 2006
Negligible Risk for Epidemics after Geophysical Disasters
Nathalie Floret,*† Jean-François Viel,*† Frédéric Mauny,*† Bruno Hoen,*† and Renaud Piarroux*†
*University Hospital of Besançon¸ Besançon, France; and †University of Franche-Comté, Besançon, France
Suggested citation for this article
After geophysical disasters (i.e., earthquakes, volcanic eruptions, tsunamis), media reports almost always stress the risk for epidemics; whether this risk is genuine has been debated. We analyzed the medical literature and data from humanitarian agencies and the World Health Organization from 1985 to 2004. Of >600 geophysical disasters recorded, we found only 3 reported outbreaks related to these disasters: 1 of measles after the eruption of Pinatubo in Philippines, 1 of coccidioidomycosis after an earthquake in California, and 1 of Plasmodium vivax malaria in Costa Rica related to an earthquake and heavy rainfall. Even though the humanitarian response may play a role in preventing epidemics, our results lend support to the epidemiologic evidence that short-term risk for epidemics after a geophysical disaster is very low.
Natural disasters are defined as "a disruption of human ecology which exceeds the community's capacity to adjust, so that outside assistance is needed" (1). Their classifications are geophysical (earthquakes, volcanic eruptions, tsunamis), hydrometeorologic (floods and wind storms), and geomorphologic (landslides). When covering these events, media outlets almost always mention the risk for epidemics that could raise the death toll well above an already staggering number of victims. According to the Centers for Disease Control and Prevention (CDC), an epidemic is the occurrence of more cases of disease than expected in a given area or among a specific group of persons over a particular period of time. For many, the word epidemic is associated with large numbers of deaths and poor living conditions, such as those that sometimes occur in refugee camps (2). The term outbreak is synonymous with epidemic and is sometimes preferred because it may not evoke the sensationalism associated with the word epidemic.
In addition to the media, other outlets draw attention to the risk for epidemics. In a letter published 3 weeks after the earthquake in Bam, Iran, in December 2004, the World Health Organization (WHO) warned that potential outbreaks of cholera, typhoid fever, malaria, and leishmaniasis were a major concern (3). WHO also issued a warning about the risk for epidemics that could develop after the 2004 tsunami: "There is an immediate INCREASED RISK of waterborne diseases, i.e., cholera, typhoid fever, shigellosis and hepatitis A and E…. Outbreaks of these diseases could occur at any moment" (4). The high risk for epidemics in areas affected by the tsunami was also pointed out by several papers published during the weeks after the disaster (5,6). Responding to WHO announcements, humanitarian agencies invested effort, time, personnel, and money in gearing up for potential epidemics, and considerable stocks of antimicrobial drugs, rehydration fluids for cholera patients, and vaccines were sent to the field.
However, not all experts support these alarming predictions. Some experts hold that disasters do not usually result in disease outbreaks but may increase disease transmission under certain circumstances (e.g., fecal contamination of water, spread of respiratory diseases in evacuation camps) (7). A similar point of view was published by VanRooyen and Leaning (8) and by de Ville de Goyet (9), who spoke of the myths propagated after disasters, some of which lead to an overestimation of the risk for epidemics.
No article has systematically reviewed published reports dealing with epidemics after geophysical disasters. The role played by outbreaks of infectious diseases in causing illness after geophysical disasters must be identified so that priorities can be defined and resources can be appropriately allocated. A systematic review of medical literature could help answer the question, "Is the risk for epidemics high after a geophysical disaster?" Consequently, we analyzed medical literature of the past 20 years and data provided by several websites and databases that compile outbreak alert messages and situation reports after disasters.
Sunday, April 16, 2006
Vaccines and Preventive Medications for Your Protection: Central Africa
Routine Vaccinations
source http://www.cdc.gov/
|
Before travel, be sure you and your children are up to date on all routine immunizations according to schedules approved by the Advisory Committee on Immunization Practice (ACIP). See the schedule for adults and the schedule for infants and children. Some schedules can be accelerated for travel.
See your doctor at least 4–6 weeks before your trip to allow time for shots to take effect. If it is less than 4 weeks before you leave, you should still see your doctor. It might not be too late to get your shots or medications as well as other information about how to protect yourself from illness and injury while traveling.
Recommended Vaccinations and Preventive Medications
The following vaccines may be recommended for your travel to Central Africa. Discuss your travel plans and personal health with a health-care provider to determine which vaccines you will need.
- Hepatitis A or immune globulin (IG). Transmission of hepatitis A virus can occur through direct person-to-person contact; through exposure to contaminated water, ice, or shellfish harvested in contaminated water; or from fruits, vegetables, or other foods that are eaten uncooked and that were contaminated during harvesting or subsequent handling.
- Hepatitis B, especially if you might be exposed to blood or body fluids (for example, health-care workers), have sexual contact with the local population, or be exposed through medical treatment. Hepatitis B vaccine is now recommended for all infants and for children ages 11–12 years who did not receive the series as infants.
- Malaria: your risk of malaria may be high in all countries in Central Africa, including cities. See your health care provider for a prescription antimalarial drug. For details concerning risk and preventive medications, see Malaria Information for Travelers to Central Africa.
- Meningococcal (meningitis), if you plan to visit countries in this region that experience epidemics of meningococcal disease during December through June, (see see Map 4-9 on the Meningoccocal Disease page).
- Rabies, pre-exposure vaccination, if you might have extensive unprotected outdoor exposure in rural areas, such as might occur during camping, hiking, or bicycling, or engaging in certain occupational activities.
- Typhoid vaccine. Typhoid fever can be contracted through contaminated drinking water or food, or by eating food or drinking beverages that have been handled by a person who is infected. Large outbreaks are most often related to fecal contamination of water supplies or foods sold by street vendors
- As needed, booster doses for tetanus-diphtheria, measles, and a one-time dose of polio vaccine for adults.
Required Vaccinations
- A certificate of yellow fever vaccination may be required for entry into certain countries in Central Africa. For detailed information, see Yellow Fever Vaccine Requirements and Information on Malaria Risk and Prophylaxis, by Country. Also, find the nearest authorized U.S. yellow fever vaccine center.
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