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The risks of acquisition of infectious diseases including the human immunodeficiency virus--1 (HIV) to practitioners and patients in the practice of optometry is discussed. Measures that reduce the risk of contracting or transmitting HIV and other infectious diseases in optometry are presented. Effective disinfection including that for HIV are discussed.
A synopsis of basic causes of the extended number of infectious diseases and changes of their clinical and epidemiological features is brought about in the article. The question is of changes of the pathogenic agents, their hosts and environment. Reasons of further evolution of infectious diseases are given.
This paper considers approaches to modeling the dynamics of infectious disease and the application of such models to nematode parasite infections in ruminants. Particularly, these models are developed to account for host genetics and may be used to assess the effects of using genetics to control nematode infections. Three main issues are critically examined: the infection transmission cycle from pasture to host to pasture, the expected genetic relationships between resistance and performance, and the risks of parasite evolution in response to genetic changes in the host. To obtain answers that are realistic and of practical use, the modeling approaches require a solid grounding in biology. This biology is formalized and described using mathematical techniques, with the models parameterized using experimental or field data. Transmission dynamics have been quantified by modeling and are backed by strong experimental data. Selection for resistance will be successful in reducing egg output, pasture larval contamination and hence subsequent larval challenge. Modeling frameworks have been developed to predict genetic relationships between resistance to infectious disease and performance in general, and genetic correlations predicted for nematode resistance are close to mean published values. These predicted correlations strengthen as the larval challenge increases and the dietary (protein) adequacy decreases, however modeling challenges remain. Lastly, although convincing experimental data is not yet available, arguments based on modeling suggest that the risks of parasite evolution in response to genetic changes in the host should be less than the risks arising from other control strategies, such as anthelmintics. Thus, modeling techniques predict that selective breeding for resistance should be an effective and sustainable complementary control measure.
T lymphocytes mediate immune defenses against infectious diseases. The major histocompatibility complex class I and class II antigen-processing pathways play an essential role in the activation of pathogen-specific T lymphocytes by presenting peptide fragments derived from pathogen-encoded proteins. The past 5 years have seen remarkable advances in our understanding of both of these antigen-processing pathways. Many new proteins that are critical to T-cell-mediated defenses against infectious pathogens have been identified and characterized. Although the direct effects of aging on antigen processing and presentation are relatively unexplored, it is likely that immunosenescence affects and is affected by the antigen-processing pathways.
In Germany, Lithuania, and Namibia different types of the HIV epidemic are present. HIV testing of health care students and their ratings of the risk of sexually acquired HIV infections and factors influencing the risk of contracting infectious diseases were analyzed. 182 German medical and dental students, 176 Lithuanian medical students, and 135 Namibian student nurses participated by completing anonymous questionnaires. The Namibian student nurses rated sexual HIV transmission risks higher than the Lithuanian and German medical students did. In general, the Lithuanian medical students rated risks of HIV transmission lowest, compared to the students in the other two samples. Risk behavior and environmental factors were most emphasized by the three student samples as having an influence on the risk of contracting infectious diseases. Thus, national prevalence of HIV influences ratings of sexual HIV transmission risks, while rating of factors influencing the risk of contracting infectious diseases are similar.
Guidelines for the treatment of blastomycosis are presented; these guidelines are the consensus opinion of an expert panel representing the National Institute of Allergy and Infectious Diseases Mycoses Study Group and the Infectious Diseases Society of America. The clinical spectrum of blastomycosis is varied, including asymptomatic infection, acute or chronic pneumonia, and extrapulmonary disease. Most patients with blastomycosis will require therapy. Spontaneous cures may occur in some immunocompetent individuals with acute pulmonary blastomycosis. Thus, in a case of disease limited to the lungs, cure may have occurred before the diagnosis is made and without treatment; such a patient should be followed up closely for evidence of disease progression or dissemination. In contrast, all patients who are immunocompromised, have progressive pulmonary disease, or have extrapulmonary disease must be treated. Treatment options include amphotericin B, ketoconazole, itraconazole, and fluconazole. Amphotericin B is the treatment of choice for patients who are immunocompromised, have life-threatening or central nervous system (CNS) disease, or for whom azole treatment has failed. In addition, amphotericin B is the only drug approved for treating blastomycosis in pregnant women. The azoles are an equally effective and less toxic alternative to amphotericin B for treating immunocompetent patients with mild to moderate pulmonary or extrapulmonary disease, excluding CNS disease. Although there are no comparative trials, itraconazole appears more efficacious than either ketoconazole or fluconazole. Thus, itraconazole is the initial treatment of choice for nonlife-threatening non-CNS blastomycosis.
Detailed standardized annual reports are analysed for 17 rural hospitals in four African countries, with admission figures of 1.2 million patients (excluding deliveries) and more than 67,000 deaths over a period of 16 years. The countries involved are Zambia, Tanzania, Kenya and Ghana. Figures on admission, causes of death and clinical case fatality rates are presented per country and per 4-year calendar period for the most important infectious diseases. The number of admissions increased substantially in 3 of the 4 countries (50-77%) between 1976 and 1990, but admission rates (per 1,000 population per year) by much less (6-25%), indicating that a large part of the increase in the volume of services was due to population growth. The number of infectious disease admissions in Ghana, however, decreased by 12% and even more in terms of admission rates (by 42%). About 75% of all admissions in children below 15 years of age were due to infections and infection related diseases; for adults this figure was 31%. Malaria is the single most important infectious disease both in terms of admissions and as a cause of death; it has increased substantially in three of the four countries. Bacterial infections, in particular pneumonia, gastroenteritis, meningitis and tuberculosis, are also important diseases in terms of admissions and deaths. On the whole they have remained at more or less the same level in 1975-1990 in terms of both admissions and deaths. Immunizable diseases and measles, once important as causes of admissions and deaths, have declined in all countries. Case fatality rates vary substantially by type of disease. They are very high for tetanus (36.7-68.8%) and meningitis (14.7-43%), and low for malaria (0.6-4.6%). However, they vary considerably in the four countries included in the study and are usually lower in children than in adults. A need for detailed studies with good "standardized" hospital records is emphasized. Representative data are needed from all hospitals in a given catchment area, with defined diagnoses for diseases and details regarding age and sex. This kind of information is highly desirable for planning and operation of curative and preventive medical care in developing countries.
The revised case definitions established by the Robert Koch Institute will become effective on 1 January 2007. The case definitions provide criteria for the reporting of mandatory notifiable infectious diseases according to the German infectious disease control act. The new case definitions take into account recent developments in laboratory methods. Furthermore in the new edition the criteria were updated and clarified if necessary. For each case definition a paragraph 'reference definition' is introduced and explained. If applicable additional information (e.g., vaccination history) to be reported was added. In this article, the major changes of the revised case definitions are described.
The past decade has witnessed a rapid transition from the first positional cloning of an infectious disease susceptibility gene (Slc11a1, also called Nramp1) in the mouse to genome-wide scans in human multicase families and the identification of potential disease-causing genes by simple inspection of the public human genome databases. Pathogen genome projects have facilitated multilocus sequence typing of pathogen isolates and studies of ecological fitness and virulence patterns in disease-causing isolates. Comparative sequence analysis of pathogen strains and functional genomics studies are now underway, hopefully providing new insight into infectious disease susceptibility.
Antimicrobial agents account for a significant proportion of drug expenditures and are used inappropriately approximately half the time in hospital practice. This has led to substantial increases in medical costs for hospitalized patients. Methods have been proposed to reduce inappropriate use of antibiotics, particularly in hospitalized patients. Two of these methods, education and control, were employed effectively by infectious disease specialists at a university teaching hospital to reduce inappropriate use of second-generation cephalosporins. These efforts resulted in significant savings of approximately $130,00 per year. The infectious disease specialist may also make major contributions to cost containment of antibiotics in other equally important areas, including other classes of antibiotics, inappropriate daily frequency, excessive duration of administration, and prevention of adverse drug reactions. The infectious disease specialist is better trained in appropriate antimicrobial use and clinically more knowledgeable in treating infections than other medical specialists and is the best-equipped member of the medical staff to educate the medical community on antibiotic use and to control antibiotic costs.
An incidence study on nosocomial infections in critically ill infectious disease patients was carried out in the intensive care unit (ICU) of a university hospital for infectious diseases over a 7-year period (1 January 1990 to 31 December 1996). A total of 660 patients who stayed in the ICU for over 48 h were prospectively observed. The patients were divided into two groups: one with central nervous system infections (442 patients) and the other with other severe infections (218 patients). The risk of nosocomial sepsis and pneumonia was significantly higher in patients suffering from severe central nervous system infections. The incidence of sepsis was 24.2% vs 11.4% (relative risk 1.95; 95% confidence interval 1.32-2.89); the incidence of pneumonia was 30.5% vs 14.7% (relative risk 2.09; 95% confidence interval 1.47-2.96). The incidence of urinary tract infection was 14.3% vs 13.3% (relative risk 1.07; 95% confidence interval 0.71-1.61). Density rates of nosocomial septic episodes were 21.1 +/- 37.1 vs 11.7 +/- 32.4 episodes/100 central venous-line days (P < 0.006). Nosocomial pneumonia occurred only in mechanically ventilated patients (36.9 +/- 61.2 vs 28.5 +/- 65.8 episodes per 1000 ventilatory days, P = 0.012). Nosocomial urinary tract infection occurred only in patients with urinary catheters (11.6 +/- 60.7 episodes/1000 urinary catheter days vs 18.7 +/- 90.1, P = 0.886). Multivariate regression analysis identified age, diagnosis of CNS infection, duration of urinary tract catheterization, the use of central venous lines and mechanical ventilation as independent risk factors of nosocomial sepsis. Duration of mechanical ventilation, use of steroids and diagnosis of CNS infection were independent risk factors of nosocomial pneumonia. A subanalysis identified tetanus patients to be at particular risk of nosocomial infections.
This article reviews the literature on infectious diseases as a cause of stillbirth. Identifying a specific infection as a cause of stillbirth is limited by many obstacles. Nevertheless, "good faith" efforts estimate that approximately 9% to 15% of stillbirths are caused by infections. Infection may be especially important as a cause of stillbirth occurring early in pregnancy. Recognized causes include syphilis, toxoplasmosis, parvovirus B-19, chorioamnionitis, and Listeria monocytogenes. Other organisms that are "purported to cause" stillbirth include the genital mycoplasmas, Chlamydia trachomatis, HIV, group B streptococci, and others. No single strategy has been developed for effective prevention of stillbirth caused by infection. Six potential strategies and their rationale are presented, but the low rate of stillbirth in most situations would require large intervention trials for hypothesis testing. Infection is an important cause of stillbirth. Within the framework if determining epidemiological etiology, research should be initiated in the role of infectious causes.
The majority of our inpatients and outpatients are senior citizens. They are in marked contrast to the majority of current medical workers who are far younger than their patients. We investigated the problems which may arise due to this age gap using a questionnaire asking about viewpoints on "health" and "infectious diseases among the elderly" Interest in general health was lower among medical workers than common citizens. Lifestyles which the public may consider to be good for health are more specific and cover a wider range than those of medical professionals. Medical staff thought home care is important for infectious diseases among the elderly. They were concerned with the appearance of resistant bacilli and considered that the type of treatment should vary in accordance with the patient's age and stamina, whereas the elderly citizens cared more strongly about the treatments result. Medical workers should understand that the general citizens have a different way of thinking about health and infectious diseases from their own.
OBJECTIVE: The purpose of this study was to summarize 3 recent high-profile infectious disease threats that have affected the United States: severe acute respiratory syndrome, West Nile virus, and anthrax. STUDY DESIGN: A systematic review was conducted with the use of Medline searches, searches of the Centers for Disease Control and Prevention website, and review by experts at the Centers for Disease Control and Prevention. RESULTS: The 3 emerging infectious diseases pose very different threats: Severe acute respiratory syndrome is a newly identified pathogen that caused an international pandemic; the West Nile virus investigation involved an old pathogen that was identified in a new location; and the anthrax attacks involved the intentional introduction of a pathogen. CONCLUSION: All 3 outbreaks highlight the importance of obstetrician-gynecologists keeping current with new information as it emerges. In this global environment, it is likely that novel disease threats will continue to emerge in the United States.
Epidemiology examines the distribution and source of a disease in a population. Understanding epidemiology and disease transmission is vital to nursing care. Infectious disease transmission requires three components: an agent (virus, bacterium, parasite or other microbe), a vulnerable host and a conducive environment. Disease spread can occur through direct contact or via indirect methods (airborne droplets, vectors, fomites, water or food). Intervention can occur by attacking the agent (e.g., using microbicides), changing the environment (e.g., providing negative pressure rooms) or strengthening the host (e.g., vaccination). Three epidemiologically relevant microbes are the SARS (severe acute respiratory syndrome)-associated coronavirus, methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile (C. difficile). The first is an emerging pathogen, and the latter two are existing agents that have mutated such that they are resistant to their standard treatments. For SARS, control measures include screening for possible cases and appropriate triage, respiratory and barrier precautions within the healthcare facility, and voluntary isolation in the community for contacts or healthcare workers who exhibit symptoms. Control measures for MRSA include the screening of patient lesions, isolating or cohorting patients who are already infected, covering wounds with impermeable dressings, treating staff and patient carriers with antibiotics, and improved hygiene. Control measures for C. difficile Control measures include paying close attention to the hygiene of the clinical setting, disinfecting using bleach and the isolation of infected patients.
The bivalent HVT/IBDV live vaccine, developed by cocultivation of the turkey herpesvirus (HVT) and infectious bursal disease virus (IBDV) vaccine in cell cultures, was quantitated. The titer of each constituent virus could be successfully determined in vitro by pretreatment of the vaccine with anti-IBDV serum or chloroform (CHCl3). Studies in vivo further demonstrated that the anti-IBDV serum-treated HVT/IBDV vaccine lost its immunogenicity by failing to induce IBDV-neutralizing antibody or to protect vaccinates from bursal atrophy after challenge exposure to infectious bursal disease. The CHCl3 treatment significantly reduced the efficacy of the vaccine to protect vaccinates against Marek's disease challenge.
This article describes infectious diseases that are of special importance to intensivists. The emphasis on epidemiology notwithstanding, it also addresses clinical, diagnostic, and treatment issues related to each infection described. The discussion avoids terrorism-related aspects of these infections, because they were very well covered in the October 2005 issue of the Critical Care Clinics.
Chytridiomycosis, an emerging infectious disease (EID) of the skin caused by the chytrid fungus, Batrachochytrium dendrobatidis, has been linked with continuing amphibian population declines in the western USA, Central America, Europe, Africa, and Australia. Genetic analysis suggests that B. dendrobatidis is a recently emerged pathogen. This article reviews the biology of this pathogenic chytrid and the evidence for chytridiomycosis as a cause of declines in amphibian populations worldwide. Data are presented to show that antimicrobial peptides, produced in granular glands of the skin and released in high concentrations into skin secretions, are highly effective in inhibiting growth of B. dendrobatidis in vitro and may provide limited protection for some species. Ongoing studies suggest a correlation between resistance to lethal infection by B. dendrobatidis and synthesis of antimicrobial peptides by the host amphibian, but further research is needed to define better the role of antimicrobial peptides in protection of amphibian populations and the effect of environmental factors upon antimicrobial peptide synthesis.