HIV surveillance: a global perspective

This article provides an overview of recommendations for HIV surveillance. Results of surveillance are used in practice to inform program decisions, judge the effectiveness of the national response, lobby for effective programs, and to provide accurate measures of trends and the absolute state of the epidemic. Recommended surveillance activities differ for different epidemic situations-epidemics that are concentrated in defined groups with high-risk behavior, and epidemics that are well established among heterosexuals in the population at large. Surveillance systems in countries with different levels of the epidemic face major challenges, most of which revolve around identifying and obtaining information from representative samples of the at-risk populations. A brief examination of surveillance systems in Botswana and Vietnam illustrate how these challenges are being met in practice. While there is room for improvement, HIV surveillance systems in many developing countries are relatively robust, and are growing stronger all the time. In most countries, however, insufficient use is made of the information generated by these systems in terms of strengthening HIV prevention and care programs.     

Historical perspective of foamy virus epidemiology and infection

Foamy viruses (FV) are complex retroviruses which are widespread in many species. Despite being discovered over 40 years ago, FV are among the least well characterized retroviruses. The replication of these viruses is different in many interesting respects from that of all other retroviruses. Infection of natural hosts by FV leads to a lifelong persistent infection, without any evidence of pathology. A large number of studies have looked at the prevalence of primate foamy viruses in the human population. Many of these studies have suggested that FV infections are prevalent in some human populations and are associated with specific diseases. More recent data, using more rigorous criteria for the presence of viruses, have not confirmed these studies. Thus, while FV are ubiquitous in all nonhuman primates, they are only acquired as rare zoonotic infections in humans. In this communication, we briefly discuss the current status of FV research and review the history of FV epidemiology, as well as the lack of pathogenicity in natural, experimental, and zoonotic infections.     

Tuberculosis and HIV infection: epidemiology, immunology, and treatment

Tuberculosis and HIV have combined to present a major threat to global public health. Each disease has a negative effect on the other, and mortality in patients with both tuberculosis and HIV is higher than that caused by either condition alone. In regions such as sub-Saharan Africa, as many as a third or more of all patients with tuberculosis have concomitant HIV infection. In urban centers in developed nations, HIV co-infection may also be quite common. Treatment of latent tuberculosis infection in persons with HIV is successful in preventing many cases of active disease, and newer ultra-short course regimens, such as those consisting of 2 months of rifampin and pyrazinamide, should aid in this effort. Diagnosis and treatment of active tuberculosis in HIV-infected patients may be difficult. Although treatment of active tuberculosis is generally successful in patients with HIV, drug interactions between anti-tuberculosis medications and antiretrovirals often complicate the matter, and expert guidance should be sought for proper management.     

Evolving epidemiology of HIV infection among adults.

Whereas new, or changes in existing, routes of transmission of HIV have not been identified in the 11 years since AIDS was identified as a clinical syndrome, changes in the epidemiology of HIV infection in the US have been identified during that period. The role of injection drug use as a risk for both parenteral and sexual transmission of HIV has increased substantially during this period. Heterosexual transmission is becoming more prominent as the epidemic continues to "mature" in the US. The likelihood that heterosexual transmission will become progressively more important in the spread of HIV in the US in the next several years seems high. The ability of individuals in some populations at risk for infection to modify risk behaviors has led to a reduction in transmission of HIV in those populations. The addition of nucleoside analog antiretrovirals and effective chemoprophylaxis for Pneumocystis carinii pneumonia has led to increases in both the quality and duration of life for some populations of HIV-infected patients. Neither a chemotherapeutic cure nor a vaccine is on the immediate horizon; education and behavior modification remain the cornerstones of current prevention efforts. For a variety of complex reasons, inappropriate scrutiny has been focused on the remote risks of health-care provider-to-patient transmission of HIV. In the past 11 years medical science has made remarkable progress in understanding the etiology, biology, epidemiology, pathogenesis, and prevention of HIV infection. Despite this progress, a great deal of work remains to be done not only in the medical and basic science arenas but also in the behavioural and sociological sciences.     

Tinea pedis: The etiology and global epidemiology of a common fungal infection

Abstract

Tinea pedis, which is a dermatophytic infection of the feet, can involve the interdigital web spaces or the sides of the feet and may be a chronic or recurring condition. The most common etiological agents are anthropophiles, including Trichophyton rubrum sensu stricto, which is the most common, followed by Trichophyton interdigitale and Epidermophyton floccosum. There has been a change in this research arena, necessitating a re-evaluation of our knowledge on the topic from a multidisciplinary perspective. Thus, this review aimed to provide a solid overview of the current status and changing patterns of tinea pedis. The second half of the twentieth century witnessed a global increase in tinea pedis and a clonal spread of one major etiologic agent, T. rubrum. This phenomenon is likely due to increases in urbanization and the use of sports and fitness facilities, the growing prevalence of obesity and the aging population. For optimal patient care and management, the diagnosis of tinea pedis should be verified by microbiological analysis. In this review, we discuss the epidemiology, clinical forms, complications and mycological characteristics of tinea pedis and we highlight the pathogenesis, prevention and control parameters of this infection.     

The epidemiology of clinically apparent HIV infection in Nicaragua

The purpose of this study was to describe the epidemic of clinically apparent human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) infection in Nicaragua and to discuss the reasons why the number of HIV patients presenting to the public health care system is increasing compared with other Central American countries. From 1987 to 2004, 1,614 HIV-positive patients were officially reported to the Nicaraguan STI/HIV/AIDS national program. Urban areas along the west-central and eastern part of Nicaragua showed the highest prevalence of AIDS, with a maximum of 54.2/year per 100,000 inhabitants. Most of the infections (91%) were acquired sexually: 65% by heterosexual contacts and 26% by homosexual contacts. The highest rate of infection was found in men aged between 20 to 39 years, with a peak around 35 to 39 years (annual incidence of 125.6 new cases per 100,000 inhabitants), and in women aged 20 to 34 years old, with a peak around 20 to 24 years (annual incidence 46.6 per 100,000 inhabitants). The male to female ratio of infection was 3:1. The death rate was stable until the beginning of 1999, but increased sharply thereafter up to 2004, the year that highly active antiretroviral therapy (HAART) was introduced in Nicaragua. In 2005, we observed a further increase in the mortality. However, our data do not represent the magnitude of the HIV/AIDS epidemic as a whole, due to a lack of systemic surveillance. HIV/AIDS in Nicaragua is in a nascent stage and is concentrated in high-risk populations, such as utility workers, commercial sex workers, men who have sex with men, prisoners, street children, housewives and police and military forces. Education of the population is an urgent need to increase HIV/AIDS-related knowledge, change attitudes, and increase safer sex practice in the community.     

Nosocomial fungal infections: epidemiology, diagnosis, and treatment.

Invasive fungal infections are increasingly common in the nosocomial setting. Furthermore, because risk factors for these infections continue to increase in frequency, it is likely that nosocomial fungal infections will continue to increase in frequency in the coming decades. The predominant nosocomial fungal pathogens include Candida spp., Aspergillus spp., Mucorales, Fusarium spp., and other molds, including Scedosporium spp. These infections are difficult to diagnose and cause high morbidity and mortality despite antifungal therapy. Early initiation of effective antifungal therapy and reversal of underlying host defects remain the cornerstones of treatment for nosocomial fungal infections. In recent years, new antifungal agents have become available, resulting in a change in standard of care for many of these infections. Nevertheless, the mortality of nosocomial fungal infections remains high, and new therapeutic and preventative strategies are needed.     

HIV among people who use drugs: a global perspective of populations at risk

This article examines the epidemiology of HIV among selected subgroups of drug users around the world who are "most at risk"--men who have sex with men, female sex workers, prisoners, and mobile populations. The underlying determinants of HIV infection among these populations include stigma, physical and sexual violence, mental illness, social marginalization, and economic vulnerability. HIV interventions must reach beyond specific risk groups and individuals to address the micro-level and macro-level determinants that shape their risk environments. Public health interventions that focus on the physical, social, and health policy environments that influence HIV risk-taking in various settings are significantly more likely to impact the incidence of HIV and other blood-borne and sexually transmitted infections across larger population groups.     

From human genome epidemiology to systems epidemiology: current progress and future perspective

The recent progress in human genome epidemiology (HuGE) is already having a profound impact on the practice of medicine and public health. First, the success of genome-wide association studies has greatly expanded the direction and content of epidemiological researches, including revealing new genetic mechanisms of complex diseases, identifying new targets for therapeutic interventions, and improving application in early screening of high-risk populations. At the same time, large-scale genomic studies make it possible to efficiently explore the gene-environment interactions, which will help better understand the biological pathways of complex diseases and identify individuals who may be more susceptible to diseases. Additionally, the emergence of systems epidemiology aims to integrate multi-omics together with epidemiological data to create a systems network that can comprehensively characterize the diverse range of factors contributing to disease development. These progress will help to apply HuGE findings into practice to improve the health of individuals and populations.