Blood and body fluid exposures among US medical students in Botswana

INTRODUCTION

Medical students from resource-rich countries who rotate in resource-limited settings have little pre-departure experience performing procedures, and lack familiarity with local equipment. The risk of blood and body fluid exposures during such rotations is significant.

AIM

1) Determine whether a simulation-based intervention reduced exposures among US medical students on a rotation in Botswana; 2) determine whether exposures were underreported; 3) describe exposures and provision of human immunodeficiency virus (HIV) post-exposure prophylaxis (PEP).

SETTING

University of Pennsylvania medical students who traveled to Botswana for a clinical rotation from July 2007 to February 2010 were eligible to participate.

PROGRAM DESCRIPTION

Twenty-two students participated in the simulation-based intervention.

PROGRAM EVALUATION

To evaluate the intervention, we used a pre/post quasi-experimental design and administered a retrospective survey. The response rate was 81.7% (67/82). Needlesticks were eliminated [8/48 (16.7%) to 0/19 (0.0%), p = 0.07]. Splashes were unchanged (6/48 [12.5%) to 3/19 (15.8%), p=>0.99]. Three students did not report their exposure. Fifteen exposures were reported to an attending, who counseled the student regarding HIV PEP. Three students did not take PEP because the exposure was low-risk.

DISCUSSION

Our intervention was associated with a decrease in needlestick exposures. Medical schools should consider training to reduce exposures abroad.

A general approach for population games with application to vaccination

Reconciling the interests of individuals with the interests of communities is a major challenge in designing and implementing health policies. In this paper, we present a technique based on a combination of mechanistic population-scale models, Markov decision process theory and game theory that facilitates the evaluation of game theoretic decisions at both individual and community scales. To illustrate our technique, we provide solutions to several variants of the simple vaccination game including imperfect vaccine efficacy and differential waning of natural and vaccine immunity. In addition, we show how path-integral approaches can be applied to the study of models in which strategies are fixed waiting times rather than exponential random variables. These methods can be applied to a wide variety of decision problems with population-dynamic feedbacks.

High-throughput lectin microarray-based analysis of live cell surface glycosylation

Lectins, plant-derived glycan-binding proteins, have long been used to detect glycans on cell surfaces. However, the techniques used to characterize serum or cells have largely been limited to mass spectrometry, blots, flow cytometry, and immunohistochemistry. While these lectin-based approaches are well established and they can discriminate a limited number of sugar isomers by concurrently using a limited number of lectins, they are not amenable for adaptation to a high-throughput platform. Fortunately, given the commercial availability of lectins with a variety of glycan specificities, lectins can be printed on a glass substrate in a microarray format to profile accessible cell-surface glycans. This method is an inviting alternative for analysis of a broad range of glycans in a high-throughput fashion and has been demonstrated to be a feasible method of identifying binding-accessible cell surface glycosylation on living cells. The current unit presents a lectin-based microarray approach for analyzing cell surface glycosylation in a high-throughput fashion.

Meta-analyses of diagnostic tests in infectious diseases: how helpful are they in the intensive care setting?

In acute-care settings timely and accurate diagnostic tools are critical for patient treatment decisions and outcomes. This review provides an up-to-date look at the meta-analyses of diagnostic test for infections in the ICU setting. There have been 3 meta-analyses investigating the value of procalcitonin as diagnostic marker of sepsis: overall, the performance of procalcitonin test was found moderate-good. Two meta-analyses evaluated methods for diagnosing intravascular device-related bloodstream infections. In general, quantitative catheter segment culture and paired quantitative blood culture showed reliable diagnostic yield, though significant heterogeneity was observed among studies. Criteria of diagnosing VAP in the intensive care unit has been evaluated in 3 systematic reviews. Overall, the cumulative results cast doubts about the usefulness of bacteriological data and quantitative cultures in the diagnosis of VAP; moreover, 2 of these meta-analyses concluded that invasive strategies for VAP diagnosis do not affect mortality.

Neuroinfection survey at a neurological ward in a Brazilian tertiary teaching hospital

OBJECTIVES

This study was undertaken to characterize the neuroinfection profile in a tertiary neurological ward.

INTRODUCTION

Neuroinfection is a worldwide concern and bacterial meningitis, tetanus and cerebral malaria have been reported as the commonest causes in developing countries.

METHODS

From 1999 to 2007, all patients admitted to the Neurology Ward of Hospital das Clínicas, São Paulo University School of Medicine because of neuroinfection had their medical records reviewed. Age, gender, immunological status, neurological syndrome at presentation, infectious agent and clinical outcome were recorded.

RESULTS

Three hundred and seventy four cases of neuroinfectious diseases accounted for 4.2% of ward admissions and the identification of infectious agent was successful in 81% of cases. Mean age was 40.5 + 13.4 years, 63.8% were male, 19.7% were immunocompromised patients and meningoencephalitis was the most common clinical presentation despite infectious agent. Viruses and bacteria were equally responsible for 29.4% of neuroinfectious diseases; parasitic, fungal and prion infections accounted for 28%, 9.6% and 3.5% respectively. Human immunodeficiency virus (HIV), herpes simplex virus 1 (HSV1), Mycobacterium tuberculosis, Treponema pallidum, Taenia solium, Schistosoma mansoni, Cryptococcus neoformans and Histoplasma capsulatum were the more common infectious pathogens in the patients. Infection mortality rate was 14.2%, of which 62.3% occurred in immunocompetent patients.

CONCLUSION

Our institution appeared to share some results with developed and developing countries. Comparison with literature may be considered as quality control to health assistance.

Modelling of Cerebral Tuberculosis: Hope for Continuous Research in Solving the Enigma of the Bottom Billion's Disease

Cerebral tuberculosis is a severe type of extrapulmonary disease that is highly predominant in children. It is thought that meningeal tuberculosis, the most common form of cerebral tuberculosis, begins with respiratory infection followed by early haematogenous dissemination to extrapulmonary sites involving the brain. Host genetic susceptibility factors and specific mycobacteria substrains could be involved in the development of this serious form of tuberculosis. In this editorial the different animal models of cerebral tuberculosis are commented, highlighting a recently described murine model in which BALB/c mice were infected by the intratracheal route with clinical isolates, which exhibited rapid dissemination and brain infection. These strains were isolated from the cerebrospinal fluid of patients with meningeal tuberculosis; they showed specific genotype and induced a peculiar immune response in the infected brain. This model could be a useful tool to study host and bacilli factors involved in the pathogenesis of the most severe form of tuberculosis.

Protein microarrays and biomarkers of infectious disease

Protein microarrays are powerful tools that are widely used in systems biology research. For infectious diseases, proteome microarrays assembled from proteins of pathogens will play an increasingly important role in discovery of diagnostic markers, vaccines, and therapeutics. Distinct formats of protein microarrays have been developed for different applications, including abundance-based and function-based methods. Depending on the application, design issues should be considered, such as the need for multiplexing and label or label free detection methods. New developments, challenges, and future demands in infectious disease research will impact the application of protein microarrays for discovery and validation of biomarkers.

Potential influence of climate change on vector-borne and zoonotic diseases: a review and proposed research plan

BACKGROUND

Because of complex interactions of climate variables at the levels of the pathogen, vector, and host, the potential influence of climate change on vector-borne and zoonotic diseases (VBZDs) is poorly understood and difficult to predict. Climate effects on the nonvector-borne zoonotic diseases are especially obscure and have received scant treatment.

OBJECTIVE

We described known and potential effects of climate change on VBZDs and proposed specific studies to increase our understanding of these effects. The nonvector-borne zoonotic diseases have received scant treatment and are emphasized in this paper.

DATA SOURCES AND SYNTHESIS

We used a review of the existing literature and extrapolations from observations of short-term climate variation to suggest potential impacts of climate change on VBZDs. Using public health priorities on climate change, published by the Centers for Disease Control and Prevention, we developed six specific goals for increasing understanding of the interaction between climate and VBZDs and for improving capacity for predicting climate change effects on incidence and distribution of VBZDs.

CONCLUSIONS

Climate change may affect the incidence of VBZDs through its effect on four principal characteristics of host and vector populations that relate to pathogen transmission to humans: geographic distribution, population density, prevalence of infection by zoonotic pathogens, and the pathogen load in individual hosts and vectors. These mechanisms may interact with each other and with other factors such as anthropogenic disturbance to produce varying effects on pathogen transmission within host and vector populations and to humans. Because climate change effects on most VBZDs act through wildlife hosts and vectors, understanding these effects will require multidisciplinary teams to conduct and interpret ecosystem-based studies of VBZD pathogens in host and vector populations and to identify the hosts, vectors, and pathogens with the greatest potential to affect human populations under climate change scenarios.

Asexual and sexual stages of Plasmodium falciparum in Nigerian pregnant women attending antenatal booking clinic

Susceptibility to infection by Plasmodium falciparum is increased in pregnant women. In sub-Saharan Africa, the consequences of maternal malaria include preterm birth, fetal growth restriction and increased infant mortality. Malaria transmission requires the circulation of viable gametocytes that can be ingested by the female mosquito taking a blood meal. This study was conducted to evaluate the presence of asexual and sexual stages of P. falciparum in pregnant women attending antenatal booking clinics in south-western Nigeria, an area hyper-endemic for malaria. Gametocyte carriage was about 13%, similar to that documented for children symptomatic for malaria in our area of study.

Epidemiological transition and the double burden of disease in Accra, Ghana

It has long been recognized that as societies modernize, they experience significant changes in their patterns of health and disease. Despite rapid modernization across the globe, there are relatively few detailed case studies of changes in health and disease within specific countries especially for sub-Saharan African countries. This paper presents evidence to illustrate the nature and speed of the epidemiological transition in Accra, Ghana's capital city. As the most urbanized and modernized Ghanaian city, and as the national center of multidisciplinary research since becoming state capital in 1877, Accra constitutes an important case study for understanding the epidemiological transition in African cities. We review multidisciplinary research on culture, development, health, and disease in Accra since the late nineteenth century, as well as relevant work on Ghana's socio-economic and demographic changes and burden of chronic disease. Our review indicates that the epidemiological transition in Accra reflects a protracted polarized model. A "protracted" double burden of infectious and chronic disease constitutes major causes of morbidity and mortality. This double burden is polarized across social class. While wealthy communities experience higher risk of chronic diseases, poor communities experience higher risk of infectious diseases and a double burden of infectious and chronic diseases. Urbanization, urban poverty and globalization are key factors in the transition. We explore the structures and processes of these factors and consider the implications for the epidemiological transition in other African cities.

Modeling the spatial spread of infectious diseases: the GLobal Epidemic and Mobility computational model

Here we present the Global Epidemic and Mobility (GLEaM) model that integrates sociodemographic and population mobility data in a spatially structured stochastic disease approach to simulate the spread of epidemics at the worldwide scale. We discuss the flexible structure of the model that is open to the inclusion of different disease structures and local intervention policies. This makes GLEaM suitable for the computational modeling and anticipation of the spatio-temporal patterns of global epidemic spreading, the understanding of historical epidemics, the assessment of the role of human mobility in shaping global epidemics, and the analysis of mitigation and containment scenarios.

Overview of a HLA-Ig based "Lego-like system" for T cell monitoring, modulation and expansion

Recent advances in molecular medicine have shown that soluble MHC-multimers can be valuable tools for both analysis and modulation of antigen-specific immune responses in vitro and in vivo. In this review, we describe the use of dimeric human and mouse major histocompatibility complexes, MHC-Ig, as part of an artificial Antigen-Presenting Cell (aAPC). MHC-Ig-based aAPC and its derivatives represent an exciting new platform technology for measuring and manipulating immune responses in vitro as well as in vivo. This new technology has the potential to help overcome many of the obstacles associated with limitations in current antigen-specific approaches of immunotherapy for the treatment of cancer, infectious diseases and autoimmunity.

Communicable Diseases: Achievements and Challenges for Public Health

The past two centuries have seen enormous achievements in control of infectious diseases, previously the leading cause of death, in large measure due to sanitation and food safety, vaccines, antibiotics and improved nutrition. This has led people to put their faith in the notion that medical science would succeed in overcoming the remaining obstacles. Vaccination has eradicated smallpox, nearly eradicated poliomyelitis and greatly reduced many other highly dangerous infections such as diphtheria, tetanus and measles. New diseases such as HIV and new forms of influenza have taken both professional and popular opinion by surprise and have renewed the challenges before the world public health community. Emergence of antibiotic-resistant strains of common organisms due to overuse of antibiotics and lack of vaccines for many dangerous microorganisms poses problems to humanity. This stresses the need for new vaccines, effective antibiotics and strengthened environmental control measures. New knowledge of the microbiological origins of cancers such as that of the cervix, stomach and liver have strengthened primary prevention and brought hope that new cures will be found for other chronic diseases of infectious origin. Tragically long delays in adopting "new" and cost effective vaccines cause hundreds of thousands of preventable deaths each year in developing and mid-level developed countries. Gains are being made in control of many tropical diseases, but malaria, tuberculosis and other infectious diseases remain enormous global problems. Research and acquisition of new knowledge, risk communication, application of currently available means and fair distribution will be great challenges to public health in the coming decades.

Pathocenosis: a holistic approach to disease ecology

The history of medicine describes the emergence and recognition of infectious diseases, and human attempts to stem them. It also throws light on the role of changing environmental conditions on disease emergence/re-emergence, establishment and, sometimes, disappearance. However, the dynamics of infectious diseases is also influenced by the relationships between the community of interacting infectious agents present at a given time in a given territory, a concept that Mirko Grmek, an historian of medicine, conceptualized with the word "pathocenosis". The spatial and temporal evolution of diseases, when observed at the appropriate scales, illustrates how a change in the pathocenosis, whether of "natural" or anthropic origin, can lead to the emergence and spread of diseases.

Using a relational database to index infectious disease information

Mapping medical knowledge into a relational database became possible with the availability of personal computers and user-friendly database software in the early 1990s. To create a database of medical knowledge, the domain expert works like a mapmaker to first outline the domain and then add the details, starting with the most prominent features. The resulting "intelligent database" can support the decisions of healthcare professionals. The intelligent database described in this article contains profiles of 275 infectious diseases. Users can query the database for all diseases matching one or more specific criteria (symptom, endemic region of the world, or epidemiological factor). Epidemiological factors include sources (patients, water, soil, or animals), routes of entry, and insect vectors. Medical and public health professionals could use such a database as a decision-support software tool.

Once a killer, always a killer: from cytotoxic T cell to memory cell

The control of the differentiation pathways followed by responding CD8(+) T cells to produce protective memory cells has been intensely studied. Recent developments have identified heterogeneity at the effector cytotoxic T-lymphocyte level within which a bona fide memory cell precursor has emerged. The challenge now is to identify the cellular and molecular factors that control this developmental pathway. This review considers aspects of the regulation of the induction of effectors, the transition of effectors to memory cells, and the dynamics of the memory population.

Zoonotic and non-zoonotic diseases in relation to human personality and societal values: support for the parasite-stress model

The parasite-stress model of human sociality proposes that humans' ontogenetic experiences with infectious diseases as well as their evolutionary historical interactions with these diseases exert causal influences on human psychology and social behavior. This model has been supported by cross-national relationships between parasite prevalence and human personality traits, and between parasite prevalence and societal values. Importantly, the parasite-stress model emphasizes the causal role of non-zoonotic parasites (which have the capacity for human-to-human transmission), rather than zoonotic parasites (which do not), but previous studies failed to distinguish between these conceptually distinct categories. The present investigation directly tested the differential predictive effects of zoonotic and non-zoonotic (both human-specific and multihost) parasite prevalence on personality traits and societal values. Supporting the parasite-stress model, cross-national differences in personality traits (unrestricted sexuality, extraversion, openness to experiences) and in societal values (individualism, collectivism, gender equality, democratization) are predicted specifically by non-zoonotic parasite prevalence.

Zoonotic and non-zoonotic diseases in relation to human personality and societal values: support for the parasite-stress model

The parasite-stress model of human sociality proposes that humans' ontogenetic experiences with infectious diseases as well as their evolutionary historical interactions with these diseases exert causal influences on human psychology and social behavior. This model has been supported by cross-national relationships between parasite prevalence and human personality traits, and between parasite prevalence and societal values. Importantly, the parasite-stress model emphasizes the causal role of non-zoonotic parasites (which have the capacity for human-to-human transmission), rather than zoonotic parasites (which do not), but previous studies failed to distinguish between these conceptually distinct categories. The present investigation directly tested the differential predictive effects of zoonotic and non-zoonotic (both human-specific and multihost) parasite prevalence on personality traits and societal values. Supporting the parasite-stress model, cross-national differences in personality traits (unrestricted sexuality, extraversion, openness to experiences) and in societal values (individualism, collectivism, gender equality, democratization) are predicted specifically by non-zoonotic parasite prevalence.

The 1918 influenza pandemic: lessons for 2009 and the future

The 1918 to 1919 H1N1 influenza pandemic is among the most deadly events in recorded human history, having killed an estimated 50 to 100 million persons. Recent H5N1 avian influenza epizootics associated with sporadic human fatalities have heightened concern that a new influenza pandemic, one at least as lethal as that of 1918, could be developing. In early 2009, a novel pandemic H1N1 influenza virus appeared, but it has not exhibited unusually high pathogenicity. Nevertheless, because this virus spreads globally, some scientists predict that mutations will increase its lethality. Therefore, to accurately predict, plan, and respond to current and future influenza pandemics, we must first better-understand the events and experiences of 1918. Although the entire genome of the 1918 influenza virus has been sequenced, many questions about the pandemic it caused remain unanswered. In this review, we discuss the origin of the 1918 pandemic influenza virus, the pandemic's unusual epidemiologic features and the causes and demographic patterns of fatality, and how this information should impact our response to the current 2009 H1N1 pandemic and future pandemics. After 92 yrs of research, fundamental questions about influenza pandemics remain unanswered. Thus, we must remain vigilant and use the knowledge we have gained from 1918 and other influenza pandemics to direct targeted research and pandemic influenza preparedness planning, emphasizing prevention, containment, and treatment.

Trends in vaccine-induced immunity to hepatitis B among Canadian street-involved youth

In Canada, universal and publicly funded hepatitis B immunization programs have been available since 1998 in all provinces and territories. This present study estimates the proportion of having vaccine-induced immunity to hepatitis B virus (HBV) infection and its associated determinants among street-involved youth aged at 15-24 years old in Canada using the data collected by the Enhanced Surveillance of Canadian Street Youth. Vaccine-induced immunity was identified by blood test results of anti-HBc negative and anti-HBs positive. Of the 4,035 participants included in this study, the overall proportion of those with vaccine-induced immunity to HBV was 51.7% during the study period compared to over 90% among the general adolescent population. The proportion of street-involved youth immunized with HBV vaccine increased from 34.7% in 1999 to 64.4% in 2005. Immunity was higher among females (aOR = 1.43, 1.17-1.75) and among those with a reported history of sexually transmitted infection (aOR = 1.30, 1.03-1.63). The proportion of youth with the immunity decreased as age increased (aOR = 0.78, 0.76-0.81, per year increase). Despite an overall increase in the proportion of Canadian street-involved youth with vaccine-induced immunity to HBV, the proportion was still significantly lower than that observed in the general adolescent population. This highlights the need to improve the access to basic health care and the immunization programs to HBV for street-involved youth through creative outreach programs and other multi-faceted approaches.

Correcting the actual reproduction number: a simple method to estimate R(0) from early epidemic growth data

The basic reproduction number, R₀, a summary measure of the transmission potential of an infectious disease, is estimated from early epidemic growth rate, but a likelihood-based method for the estimation has yet to be developed. The present study corrects the concept of the actual reproduction number, offering a simple framework for estimating R₀ without assuming exponential growth of cases. The proposed method is applied to the HIV epidemic in European countries, yielding R₀ values ranging from 3.60 to 3.74, consistent with those based on the Euler-Lotka equation. The method also permits calculating the expected value of R₀ using a spreadsheet.

Hospitalization of newborns and young infants for chickenpox in France

Chickenpox is often considered more severe during the first year of life, but its course is usually mild during the first 3 months of life, presumably owing to the persistence of maternal antibodies. Hospitalization and intravenous acyclovir therapy are generally restricted to severe cases but also systematically recommended in newborns in France, irrespective of the clinical severity of the infection. This recommendation was launched in 1998 when Varicella zoster virus (VZV)-specific immunoglobulins were not available in the country and has remained unchanged since. The aim of this prospective observational study was to describe complications of varicella infection in a population of 745 children hospitalized for varicella before 1 year of age, with a specific focus on newborns. Complications occurred in 65% of cases. They were very rare before the age of 1 month (10%) but their incidence then increased progressively with age and probably the disappearance of maternal antibodies: 42% (1-2 months), 66% (3-5 months), 70% (6-8 months), and 79% (9-12 months). Conclusion Chickenpox is usually mild in newborns because most of them are protected by VZV maternal antibodies. Unless the absence of maternal VZV immunity is demonstrated, newborns with mild chickenpox should not require antiviral therapy.

Interferons as Therapy for Viral and Neoplastic Diseases: From Panacea to Pariah to Paragon

For more than 20 years after the excitement engendered by their discovery in 1957 as antiviral agents, there were no significant clinical uses of interferons; however, following their cloning they have been employed as effective treatment for several viral, autoimmune, and neoplastic diseases.

Backbone and side chain (1)H, (13)C, and (15)N NMR assignments for the organic hydroperoxide resistance protein (Ohr) from Burkholderia pseudomallei

Burkholderia pseudomallei is a NIAID Category B microorganism responsible for melioidosis. Here we report backbone and side chain NMR assignments for the 139-residue, homodimeric, organic hydroperoxide resistance protein (Ohr) from this organism.

Structural genomics and drug discovery for infectious diseases

The application of structural genomics methods and approaches to proteins from organisms causing infectious diseases is making available the three dimensional structures of many proteins that are potential drug targets and laying the groundwork for structure aided drug discovery efforts. There are a number of structural genomics projects with a focus on pathogens that have been initiated worldwide. The Center for Structural Genomics of Infectious Diseases (CSGID) was recently established to apply state-of-the-art high throughput structural biology technologies to the characterization of proteins from the National Institute for Allergy and Infectious Diseases (NIAID) category A-C pathogens and organisms causing emerging, or re-emerging infectious diseases. The target selection process emphasizes potential biomedical benefits. Selected proteins include known drug targets and their homologs, essential enzymes, virulence factors and vaccine candidates. The Center also provides a structure determination service for the infectious disease scientific community. The ultimate goal is to generate a library of structures that are available to the scientific community and can serve as a starting point for further research and structure aided drug discovery for infectious diseases. To achieve this goal, the CSGID will determine protein crystal structures of 400 proteins and protein-ligand complexes using proven, rapid, highly integrated, and cost-effective methods for such determination, primarily by X-ray crystallography. High throughput crystallographic structure determination is greatly aided by frequent, convenient access to high-performance beamlines at third-generation synchrotron X-ray sources.

Infectious hepatopathies in dogs and cats

This article serves to review the various infectious diseases that affect the liver primarily or as a part of systemic infection. Although bacterial infections are probably the most common cause of infectious hepatitis, the clinician should be aware of other potential organisms and other commonly involved systems. Therefore, this article includes a description of common bacterial, mycobacterial, viral, fungal, protozoal, parasitic, and rickettsial diseases in dogs and cats.

Porcine circovirus type 2 and porcine circovirus-associated disease

Porcine circovirus type 2 (PCV2) belongs to the viral family Circoviridae and to the genus Circovirus. Circoviruses are small, single-stranded nonenveloped DNA viruses that have an unsegmented circular genome. PCV2 is the primary causative agent of several syndromes collectively known as porcine circovirus-associated disease (PCVAD). Many of the syndromes associated with PCVAD are a result of coinfection with PCV2 virus and other agents such as Mycoplasma and porcine reproductive and respiratory syndrome virus. PCV2 infection is present in every major swine-producing country in the world, and the number of identified cases of PCVAD is rapidly increasing. In the United States, the disease has cost producers an average of 3-4 dollars per pig with peak losses ranging up to 20 dollars per pig. The importance of this disease has stimulated investigations aimed at identifying risk factors associated with infection and minimizing these risks through modified management practices and development of vaccination strategies. This paper provides an overview of current knowledge relating to PCV2 and PCVAD with an emphasis on information relevant to the swine veterinarian.

Infectious disease diagnostic assays

Dogs and cats are commonly exposed to infectious disease agents. The following article is an update on the most common infectious disease assays used in small animal practice. In some situations, results of pathogen-specific molecular diagnostic assays can be used to assist the practicing veterinarian in the management of patients with infectious diseases. However, with some infectious disease agents, the assays are positive in healthy and ill animals and can be falsely negative and so the predictive values of the assays vary.

Improved general health of international adoptees, but immunization status still insufficient

We studied the demographic and clinical data from 495 adopted children seen between January 2002 and January 2007 to evaluate the medical condition and immunization status of international adoptees. The data of children from Chinese origin (53.5%) were compared to children arriving from other countries. Medical problems requiring treatment were present in 42.8% of the children. Parasitic gastrointestinal infection (22.0%) and skin abnormalities (22.4%) were diagnosed most often. Hepatitis B (1.2%) and tuberculosis (1%) were documented in some children; HIV, hepatitis C, and syphilis were not seen in any of the children. Antibody levels against diphtheria and tetanus were insufficient in about half of all children, particularly in those from China. In conclusion, most adoptive children had a good general health, with only a few having major medical problems. Many adoptive children had an inadequate immunization status.

Apolipoprotein E: structure determines function, from atherosclerosis to Alzheimer's disease to AIDS

Apolipoprotein (apo) E has roles beyond lipoprotein metabolism. The detrimental effects of apoE4 in cardiovascular, neurological, and infectious diseases correlate with its structural features (e.g., domain interaction) that distinguish it from apoE3 and apoE2. Structure/function studies revealed that apoE2 is severely defective in LDL receptor binding because of a structural difference that alters the receptor binding region and helped unravel the mechanism of type III hyperlipoproteinemia. ApoE4 is the major genetic risk factor for Alzheimer's disease and sets the stage for neuropathological disorders precipitated by genetic, metabolic, and environmental stressors. ApoE also influences susceptibility to parasitic, bacterial, and viral infections. In HIV-positive patients, apoE4 homozygosity hastens progression to AIDS and death and increases susceptibility to opportunistic infections. The next phase in our understanding of apoE will be characterized by clinical intervention to prevent or reverse the detrimental effects of apoE4 by modulating its structure or blocking the pathological processes it mediates.

OUR COMMON ENEMY: COMBATTING THE WORLD'S DEADLIEST VIRUSES TO ENSURE EQUITY HEALTH CARE IN DEVELOPING NATIONS

In a previous issue of Zygon (Carvalho 2007), I explored the role of scientists-especially those engaging the science-religion dialogue-within the arena of global equity health, world poverty, and human rights. I contended that experimental biologists, who might have reduced agency because of their professional workload or lack of individual resources, can still unite into collective forces with other scientists as well as human rights organizations, medical doctors, and political and civic leaders to foster progressive change in our world. In this article, I present some recent findings from research on three emerging viruses-HIV, dengue, and rotavirus-to explore the factors that lead to the geographical expansion of these viruses and the increase in frequency of the infectious diseases they cause. I show how these viruses are generating problems for geopolitical stability, human rights, and equity health care for developing nations that are already experiencing a growing poverty crisis. I suggest some avenues of future research for the scientific community for the movement toward resolution of these problems and indicate where the science-religion field can be of additional aid.

Perceived threat, risk perception, and efficacy beliefs related to SARS and other (emerging) infectious diseases: results of an international survey

PURPOSE

To study the levels of perceived threat, perceived severity, perceived vulnerability, response efficacy, and self-efficacy for severe acute respiratory syndrome (SARS) and eight other diseases in five European and three Asian countries.

METHOD

A computer-assisted phone survey was conducted among 3,436 respondents. The questionnaire focused on perceived threat, vulnerability, severity, response efficacy, and self-efficacy related to SARS and eight other diseases.

RESULTS

Perceived threat of SARS in case of an outbreak in the country was higher than that of other diseases. Perceived vulnerability of SARS was at an intermediate level and perceived severity was high compared to other diseases. Perceived threat for SARS varied between countries in Europe and Asia with a higher perceived severity of SARS in Europe and a higher perceived vulnerability in Asia. Response efficacy and self-efficacy for SARS were higher in Asia compared to Europe. In multiple linear regression analyses, country was strongly associated with perceived threat.

CONCLUSIONS

The relatively high perceived threat for SARS indicates that it is seen as a public health risk and offers a basis for communication in case of an outbreak. The strong association between perceived threat and country and different regional patterns require further research.

Modeling amantadine treatment of influenza A virus in vitro

We analyzed the dynamics of an influenza A/Albany/1/98 (H3N2) viral infection, using a set of mathematical models highlighting the differences between in vivo and in vitro infection. For example, we found that including virion loss due to cell entry was critical for the in vitro model but not for the in vivo model. Experiments were performed on influenza virus-infected MDCK cells in vitro inside a hollow-fiber (HF) system, which was used to continuously deliver the drug amantadine. The HF system captures the dynamics of an influenza infection, and is a controlled environment for producing experimental data which lend themselves well to mathematical modeling. The parameter estimates obtained from fitting our mathematical models to the HF experimental data are consistent with those obtained earlier for a primary infection in a human model. We found that influenza A/Albany/1/98 (H3N2) virions under normal experimental conditions at 37 degrees C rapidly lose infectivity with a half-life of approximately 6.6+/-0.2 h, and that the lifespan of productively infected MDCK cells is approximately 13 h. Finally, using our models we estimated that the maximum efficacy of amantadine in blocking viral infection is approximately 74%, and showed that this low maximum efficacy is likely due to the rapid development of drug resistance.

Age-associated T-cell Clonal Expansions (TCE) in vivo—Implications for Pathogen Resistance

Age-related T-cell clonal expansions (TCE) are an incompletely understood disturbance in T-cell homeostasis found frequently in old humans and experimental animals. These accumulations of CD8 T-cells have the potential to distort T-cell population balance and reduce T-cell repertoire diversity above and beyond the changes seen in the aging of T-cell pool in the absence of TCE. This chapter discusses our current knowledge of the role of these expansions in health and disease, with a special focus on their influence upon immune defense against infectious diseases.

The book reopened on infectious diseases

Emerging infectious diseases represent a major challenge to human health worldwide. The risk of evolving new infectious pathogens has been intensifying due to urbanization, demographic changes, air travel, inappropriate use of antibiotics, and climate change. These pathogens can affect humans from urban centers to the remotest corners of the globe. Far from being a scourge of the past, infectious diseases are relevant for the world today.

Evolution of pathogens in a man-made world

Human activities have resulted in substantial, large-scale environmental modifications, especially in the past century. Ecologists and evolutionary biologists are increasingly coming to realize that parasites and pathogens, like free-living organisms, evolve as the consequence of these anthropogenic changes. Although this area now commands the attention of a variety of researchers, a broad predictive framework is lacking, mainly because the links between human activities, the environment and parasite evolution are complex. From empirical and theoretical examples chosen in the literature, we give an overview of the ways in which humans can directly or indirectly influence the evolution of different traits in parasites (e.g. specificity, virulence, polymorphism). We discuss the role of direct and indirect factors as diverse as habitat fragmentation, pollution, biodiversity loss, climate change, introduction of species, use of vaccines and antibiotics, ageing of the population, etc. We also present challenging questions for further research. Understanding the links between anthropogenic changes and parasite evolution needs to become a cornerstone of public health planning, economic development and conservation biology.

Stroke in central nervous system infections

BACKGROUND

Stroke subtypes and etiology may differ between developing and developed countries. Infections are a relatively common cause of stroke in tropical regions.

OBJECTIVE

To review the main infectious diseases associated with stroke.

DISCUSSION

Prevalence of stroke in HIV patients is around 1%. Pathogenic mechanisms include HIV vasculopathy, vasculitis, cardioembolism, acquired hypercoagulability, and the effect of opportunistic infections. Treatment with protease inhibitors has been associated with premature atherosclerotic vascular disease. Emerging viral infections that are associated with stroke include viral hemorrhagic fevers, Japanese encephalitis, dengue, and West Nile virus. Vasculitis involving perforating vessels of the brain is a cerebrovascular complication of tuberculous meningitis. Small, medium, and large arteries of the anterior circulation can be involved. A progressive intracranial arteriopathy afterLeptospira interrogansinfection has been described, which involves the large intracranial arteries. Cerebrovascular complications of mycosis are associated with large vessel vasculitis, direct vessel damage by invasion or embolization, and subarachnoid hemorrhage due to mycotic aneurysm rupture. Pathological findings of cerebral malaria include diffuse cerebral edema, perivascular ring hemorrhages, white matter necrosis, parenchyma petechial hemorrhages, occlusion of brain vessels, and sequestration of infected erythrocytes in cortical and perforating arteries. Stroke can occur in subarachnoid neurocysticercosis and the lesions in such cases consist mostly of deep lacunar infarctions resulting from endarteritis of small penetrating arteries. Cardiac arrhythmias, congestive heart failure, apical aneurysm, and mural thrombus are the conditions that predispose patients with American trypanosomiasis to cardioembolism. Gnathostoma spinigerum infestation is a cause of hemorrhagic stroke in Asia.

CONCLUSION

Infectious and tropical diseases should be included in the differential diagnoses of stroke.

International Circumpolar Surveillance, an Arctic network for the surveillance of infectious diseases

Peoples of the Arctic and sub-Arctic regions live in social and physical environments that differ substantially from those of their more southern-dwelling counterparts. The cold northern climate keeps people indoors, amplifying the effects of household crowding, smoking, and inadequate ventilation on person-to-person spread of infectious disease. The emergence of antimicrobial drug resistance among bacterial pathogens, the reemergence of tuberculosis, the entrance of HIV into Arctic communities, and the spectre of pandemic influenza or the sudden emergence and introduction of new viral pathogens such as severe acute respiratory syndrome are of increasing concern to residents, governments, and public health authorities. The International Circumpolar Surveillance system is a network of hospital, public health agencies, and reference laboratories throughout the Arctic linked together to collect, compare, and share uniform laboratory and epidemiologic data on infectious diseases and assist in the formulation of prevention and control strategies.

Mathematical functions for modeling the variation of specific medical criteria in some infectious diseases

The paper presents the definition of rules for the medical algorithms in some infectious diseases and also the mathematical functions for modeling: interrogation rules to elaborate specific concepts and work methods in HIV/AIDS infection, interrogation rules to elaborate specifically concepts and work methods in SEPSIS, initial conditions regarding the introduction of the notion of stochastic correlation coefficient, determination of the the stochastic correlation coefficient through the method of reciprocal comparison of the variables, determination of the influential ponders through reciprocal comparison of the characteristics. models for the study of the variation of the specific medical criteria of some infectious diseases in the case of adopting the analysis method of reciprocal non comparison.

Oral biofilms, periodontitis, and pulmonary infections

Bacteria from the oral biofilms may be aspirated into the respiratory tract to influence the initiation and progression of systemic infectious conditions such as pneumonia. Oral bacteria, poor oral hygiene, and periodontitis seem to influence the incidence of pulmonary infections, especially nosocomial pneumonia episodes in high-risk subjects. Improved oral hygiene has been shown to reduce the occurrence of nosocomial pneumonia, both in mechanically-ventilated hospital patients and non-ventilated nursing home residents. It appears that oral colonization by potential respiratory pathogens, possibly fostered by periodontitis, and possibly by bacteria specific to the oral cavity or to periodontal diseases contribute to pulmonary infections. Thus, oral hygiene will assume an even more important role in the care of high-risk subjects--patients in the hospital intensive care and the elderly. The present paper critically reviews the recent literature on the effect of oral biofilms and periodontitis on pneumonia.

Technical tip: new tools for protection from sharps injuries

Sharps injuries are an area of concern for healthcare workers. This article discusses clinical use of a blunt suture needle and an absorbable skin staple in upper limb operations. These devices may reduce the need for sharp needles in the surgical field during selected procedures on the upper limb.

Agreement of decision analyses and subsequent clinical studies in infectious diseases

PURPOSE

Decision analysis techniques can compare management strategies when there are insufficient data from clinical studies to guide decision making. We compared the outcomes of decision analyses and subsequent clinical studies in the infectious disease literature to assess the validity of the conclusions of the decision analyses.

METHODS

A search strategy to identify decision analyses in infectious disease topics published from 1990 to 2005 was developed and performed using PubMed. Abstracts of all identified articles were reviewed, and infectious disease-related decision analyses were retained. Subsequent clinical trials and observational studies that corresponded to these decision analyses were identified using prespecified search strategies. Clinical studies were considered a match for the decision analysis if they assessed the same patient population, intervention, and outcome. Agreement or disagreement between the conclusions of the decision analysis and clinical study were determined by author review.

RESULTS

The initial PubMed search yielded 318 references. Forty decision analyses pertaining to 29 infectious disease topics were identified. Of the 40, 16 (40%) from 13 infectious disease topics had matching clinical studies. In 12 of 16 (75%), conclusions of at least 1 clinical study agreed with those of the decision analysis. Three of the 4 decision analyses in which conclusions disagreed were from the same topic (management of febrile children).

CONCLUSIONS

There was substantial agreement between the conclusions of decision analyses and clinical studies in infectious diseases, supporting the validity of decision analysis and its utility in guiding management decisions.

A model for the spread and control of pandemic influenza in an isolated geographical region

In the event of an influenza pandemic, the most probable way in which the virus would be introduced to an isolated geographical area is by an infected traveller. We use a mathematical model, structured on the location at which infection occurs and based on published parameters for influenza, to describe an epidemic in a community of one million people. The model is then modified to reflect a variety of control strategies based on social distancing measures, targeted antiviral treatment and antiviral prophylaxis and home quarantine, and the effectiveness of the strategies is compared. The results suggest that the only single strategy that would be successful in preventing an epidemic (with R0=2.0) is targeted antiviral treatment and prophylaxis, and that closing schools combined with either closing work places or home quarantine would only prevent such an epidemic if these strategies were combined with a modest level of antiviral coverage.

The role of internists during epidemics, outbreaks, and bioterrorist attacks

Internists are well-positioned to play significant roles in recognizing and responding to epidemics, outbreaks, and bioterrorist attacks. They see large numbers of patients with various health problems and may be the patients' only interaction with the medical community for symptoms resulting from infectious diseases and injuries from radiation, chemicals, and/or burns. Therefore, Internists must understand early warning signs of different bioterrorist and infectious agents, proper reporting channels and measures, various ways that they can assist the public health response, and roles of different local, state, and federal agencies. In addition, it is important to understand effects of a public health disaster on clinic operations and relevant legal consequences.

Improving influenza vaccination rates of high-risk inner-city children over 2 intervention years

PURPOSE

Influenza immunization rates among children with high-risk medical conditions are disappointingly low, and relatively few data are available on raising rates, particularly over 2 years. We wanted to determine whether interventions tailored to individual practice sites improve influenza immunization rates among high-risk children in inner-city health centers over 2 years.

METHOD

A before-after trial to improve influenza immunization of children was conducted at 5 inner-city health centers (residencies and faith-based). Sites selected interventions from a menu (eg, standing orders, patient and clinician reminders, education) proved to increase vaccination rates, which were directed at children aged 2 to 17 years with high-risk medical conditions. Intervention influenza vaccination rates and 1 and 2 years were compared with those of the preintervention year (2001-2002) and of a comparison site.

RESULTS

Influenza vaccination rates improved modestly from baseline (10.4%) to 13.1% during intervention year 1 and to 18.7% during intervention year 2 (P <.001), with rates reaching 31% in faith-based practices. Rates increased in all racial and age-groups and in Medicaid-insured children. The increase in rates was significantly greater in intervention health centers (8.3%) than in the comparison health center (0.7%; P <.001). In regression analyses that controlled for demographic factors, vaccination status was associated with intervention year 1 (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.6-2.2) and with intervention year 2 (OR, 2.8; 95% CI, 2.3-3.4), as well as with practice type. Adolescents had lower vaccination rates than children 2 to 6 years old (OR, 0.6; 95% CI, 0.5-0.7).

CONCLUSIONS

Tailored interventions selected from a menu of interventions modestly increased influenza vaccination rates over 2 years at health centers serving children from low-income families. We recommend this strategy for faith-based practices and residencies with 1 practice site, but further research is needed on multisite practices and to achieve higher influenza vaccination rates.

Community-acquired methicillin-resistant Staphylococcus aureus: prevalence and risk factors

Reference/Citation: Salgado CD, Farr BM, Calfee DP. Community-acquired methicillin-resistant Staphylococcus aureus: a meta-analysis of prevalence and risk factors. Clin Infect Dis.20033613113912522744.

Clinical Question: What are the prevalence rates and risk factors associated with community-acquired methicillin-resistant Staphylococcus aureus (MRSA)?

Data Sources: Studies were identified by searching MEDLINE (January 1966–February 2002) and abstracts from scientific meetings (1996–2001). Reviews of citations and reference lists were performed to identify additional eligible studies. The search terms included Staphylococcus aureus, infection, colonization, methicillin resistance, community-acquired, community-onset, prevalence, frequency, and risk factors.

Study Selection: The search was limited to English-language investigations identified from the electronic and manual searches. Studies were divided into 2 groups, as follows: group 1, retrospective or prospective studies that reported the prevalence of community-acquired MRSA (CA-MRSA) among hospital patients who were colonized (presence of bacteria without infection) or infected with MRSA; and group 2, studies that reported the prevalence of MRSA colonization in the community. The studies were evaluated independently by 2 authors, and case reports were excluded.

Data Extraction: Data extraction and study quality assessment procedures were not fully explained. The outcome measures for hospital patients were definitions of CA-MRSA used in the study, prevalence of CA-MRSA, sample size, number and type of risk factors assessed, and number of patients with ≥1 health care–associated risk factor. The studies were grouped based on type, retrospective or prospective. The pooled prevalence of CA-MRSA was calculated for each group (retrospective or prospective) and was limited to the prevalence among patients with MRSA. The proportion of patients who reported ≥1 health care–associated risk factor was also calculated. The outcome measures among community members were prevalence of MRSA, sample size, number and type of risk factors assessed, number of members with ≥1 risk factor, and MRSA strain type, when available. The studies were grouped based on the population surveyed (surveillance cultures, contacts with MRSA-colonized individuals, or sport team members or day care contacts). The pooled prevalence of MRSA colonization and the proportion of members with ≥1 reported risk factor were calculated for each of the study populations listed above. The proportion of CA-MRSA strains that represented typical nosocomial (infection that develops in the hospital) strains was also determined. Chi-square analysis was performed to compare proportions and to determine heterogeneity among the studies.

Main Results: Specific search criteria identified 104 studies for review, of which 57 met inclusion and exclusion criteria. Thirty-nine studies focused on CA-MRSA among hospital patients who were colonized or infected with MRSA. Of these, 32 groups (27 retrospective, 5 prospective) reported the prevalence of CA-MRSA using clinical specimens. Seven groups identified risk factors of CA-MRSA among patients previously diagnosed with MRSA. Thirteen different definitions of CA-MRSA were used in 31 of these studies, and 8 groups did not report the definitions used. The isolation of MRSA within 48 hours of hospital admission, with or without recent admission to a hospital or long-term care facility, or previous history of MRSA colonization were the most common definitions in the studies.

The risk factors included recent hospitalization (range, 1–24 months before identification of MRSA infection or colonization), recent outpatient visit (usually within 12 months), recent nursing home admission (usually within 12 months), recent antibiotic exposure (range, 1–12 months), chronic illness (eg, end-stage renal disease, diabetes, or malignancy), injection drug use, and close contact with a person who had risk factor(s) for MRSA acquisition. The presence of health care–associated risk factors was examined in 17 of the retrospective studies, and the median number of factors studied was 2 (range, 1–6). Among 4121 patients in these studies, 86.1% were found to have ≥1 health care–associated risk factor. All authors of prospective studies (5) examined health care–associated risk factors, and the median number of factors studied was 4 (range, 2–4). Among the 636 patients, 86.9% had ≥1 health care–associated risk factor. In the 7 studies with 515 patients previously diagnosed with MRSA, 84.7% had ≥1 health care–associated risk factor. The most common risk factors assessed in the 17 retrospective studies were recent hospitalization and chronic illness requiring health care visits.

The pooled CA-MRSA prevalence was 30.2% (range, 1.9%– 96%) among 5932 patients from the 27 retrospective studies and 37.3% (range, 18.2%–51.2%) among 636 patients from the 5 prospective studies. Eighteen groups reported the prevalence of MRSA colonization in the community. Ten of these reported MRSA prevalence using surveillance cultures, 4 examined colonization status of household contacts with discharged hospital patients with nosocomial MRSA colonization, and 4 reported colonization status of sports team members or day care contacts of persons colonized with MRSA. In the 10 surveillance studies, the pooled MRSA colonization prevalence was 1.3% (95% confidence interval [CI], 1.04%–1.53%; range, 0.2%– 7.4%) among 8350 community members. Nine of these studies were stratified based on culture samples taken before the assessment of risk factors, and among 4825 people, the pooled MRSA colonization prevalence was 2.1%. When examining health care–associated risk factors, the median number of factors studied was 5 (range, 1–10), and 47.5% with MRSA had ≥1 health care–associated risk factor. The risk factors included those previously identified. In the remaining surveillance study, the MRSA colonization prevalence was 0.20% among 3525 people without prior health care contact. Compared with subjects in the 9 stratified studies with a health care contact, subjects in this study were 90% less likely to have MRSA (relative risk, 0.10; 95% CI, 0.05–0.21). Cultures for 3898 subjects in 7 of the 10 surveillance studies were obtained at the time of a hospital admission, an outpatient clinic visit, or an emergency department visit, and the pooled prevalence of MRSA colonization was 1.8%. In 3 studies in which cultures were obtained outside of a health care facility (schools, day care centers, homeless shelters, or military bases), the pooled MRSA colonization prevalence among 4452 subjects was reported to be 0.76%. Therefore, subjects in a health care facility were 2.35 times more likely to carry MRSA than were subjects outside of a health care facility (95% CI, 1.56–3.53). In one study examining 94 subjects in a semiclosed community, the prevalence of MRSA colonization was 7.4%. These subjects were 36 times more likely to carry MRSA than were subjects who were not in a semiclosed community (95% CI, 13.7–94.7).

The studies also identified 70 MRSA isolates (pure form of an organism in a microbial culture) from subjects who reported no health care–associated risk factors. Strain typing was performed with 32 isolates, and 29 (91%) isolates were similar to strains identified in hospitals. The colonization status of 191 household contacts of 93 patients with nosocomial MRSA colonization discharged from the hospital was examined in 4 studies. The results demonstrated that 17.8% of the contact subjects were colonized with a strain of MRSA having the same antibiogram (record of the susceptibility of bacteria to antibiotics) as the index case (initial individual with the strain). The authors reported that subjects who had household contacts with MRSA-colonized patients were 14 times more likely to be colonized than were community subjects without a known MRSA contact (95% CI, 9.8–20.1). In 4 studies examining 517 sports team members or day care contacts of persons known to be colonized with MRSA, 5.4% demonstrated colonization of MRSA with the same strain as the index case.

Conclusions: Based on the available data, the prevalence of MRSA among community members without health care–associated risk factors was relatively low. However, 85% of hospital patients diagnosed with CA-MRSA and 47.5% of healthy community members colonized with MRSA were found to have ≥1 health care–associated risk factor. The risk factors identified were recent hospitalization, outpatient visit, nursing home admission, antibiotic exposure, chronic illness, injection drug use, and close contact with a person with risk factor(s). Most MRSA colonization occurred among community members who had health care–associated risk factors or contact with persons with risk factors. The evidence indicated that control of MRSA in the community may require control of MRSA in the health care setting (hospital, health care office, and nursing home). The absence of a standardized definition for CA-MRSA and questions regarding the actual site of colonization versus acquisition should be considered in the interpretation of these findings.

Association between infectious diseases and type 1 diabetes: a case-crossover study

BACKGROUND

To investigate the role of infectious diseases in the development of type 1 diabetes, this study estimated the relative risks of type 1 diabetes immediately after infectious diseases.

RESEARCH DESIGN AND METHODS

A case-crossover design was employed. Information on infectious diseases during 407 d before the onset of type 1 diabetes was collected from medical records and parents' interviews for 260 patients in Chinese type 1 diabetes registry. The frequency of infectious diseases in 42 d before the onset of type 1 diabetes was compared with either the usual frequency of infectious diseases over the past year or the actual frequency of infectious diseases in a comparable 42-d control period.

RESULTS

Forty-eight (18%) patients were reported to have infectious diseases during this period based on medical records and interviews with parents. The relative risk of type 1 diabetes onset was markedly elevated to 10.1 (5.6, 17.9) immediately after infectious diseases, suggesting the role of infections as a precipitator. The relative risk decreased gradually before and after 42 d and was similar between male and female patients.

CONCLUSION

The results showed that infectious diseases are associated with a large and transient increase in the risk of type 1 diabetes during 42 d after the infection.