Hacia donde se encamina la epidemia de infección por VIH y SIDA? / HIV and AIDS: where is the epidemic going?

Routine surveillance of HIV (human immunodeficiency virus) infection and AIDS has been established over the past decade in many countries around the world. HIV estimates derived from empirical data are essential to the assessment of the HIV situation in different parts of the world and trends are used in tracking the development of regional epidemics, thereby keeping intervention activities focused on realities. As of the end of 1995, and following an extensive country-by-country review of HIV/AIDS data, a cumulative total of 6 million AIDS cases were estimated to have occurred in adults and children worldwide and currently 20.1 million adults are estimated to be alive and infected with HIV or have AIDS. Of the total prevalent HIV infections, the majority remain concentrated in eastern, central and southern Africa, but the epidemic is evolving with spread of infection from urban to rural areas, as well as to West and South Africa, India and Southeast Asia, and to a lesser extent­with proportional shifts to heterosexual infections­in North America, Western Europe and Latin America. While the longer-term dimensions of the HIV epidemic at global level cannnot be forecast with confidence, WHO currently projects a cumulative total of close to 40 million HIV infections in men, women and children by the year 2000. By that time, the male:female ratio of new infections will be close to 1:1. Recent trends indicate that HIV prevalence levels may be stabilizing or even decreasing among pregnant women in southern Zaire and parts of Uganda, among military recruits aged 21 in Thailand, and in some populations of northern Europe and the USA. While these changes may take place as part of the intrinsic dynamic of the epidemic, there is some evidence that declines in HIV prevalence are related to declines in HIV incidence which are, at least partly, due to prevention efforts. The challenge of surveillance and evaluation methods is now to identify the ingredients of success which may reveal a glimmer of hope.

En el transcurso del último decenio, muchos países en todo el mundo han establecido una vigilancia sistemática para casos de sida y de infección por virus de la inmunodeficiencia humana (VIH). Las estimaciones de la carga de infección por VIH que derivan de datos empíricos son indispensables para evaluar la situación en diferentes partes del mundo y las tendencias se emplean para seguir la trayectoria de epidemias regionales y así poder basar las actividades de intervención en hechos concretos. Se estimó a fines de 1995, a raíz de un extenso análisis de datos sobre la infección por VIH y el sida efectuado país por país, que ha habido un total acumulativo de 6 millones de casos de sida en adultos y niños en todo el mundo y que actualmente 20,1 millones de adultos están infectados por VIH o tienen sida. De la prevalencia total de infecciones por VIH, la mayor parte se concentra en África oriental, central y meridional, pero la epidemia está evolucionando y la infección se está propagando de las zonas urbanas a las rurales, y también al sur y occidente de África, a la India y al Asia Sudoriental y, en menor escala ­con cambios similares en la proporción de infecciones heterosexuales­, a América del Norte, Europa occidental y América Latina. Aunque no se puede confiablemente pronosticar en el largo plazo la magnitud de la epidemia de infección por VIH en el mundo, la proyección actual de la OMS es de un total acumulativo cercano a los 40 millones de infecciones por VIH en hombres, mujeres y niños para el año 2000. Llegado ese año, la razón de infecciones en hombres a infecciones en mujeres se aproximará a 1:1. Las tendencias más recientes indican que las tasas de prevalencia de VIH podrían estar en vías de estabilización o incluso de reducción en mujeres embarazadas en el sur del Zaire y en partes de Uganda, en reclutas militares de 21 años de edad en Tailandia y en algunas poblaciones del norte de Europa y de los Estados Unidos de América. Si bien estos cambios pueden ocurrir como parte de la dinámica intrínseca de la epidemia, hay indicios de que las reducciones de la prevalencia de la infección por VIH están relacionadas con disminuciones de la incidencia, que se deben, al menos en parte, a las actividades de prevención. El actual reto de los métodos de vigilancia y evaluación radica en descubrir aquellos ingredientes que han llevado al éxito y que pueden ofrecer un rayo de esperanza.

Estimation of adult HIV prevalence as of the end of 1994 in India.

It is estimated that as of the end of 1994 approximately 1,750,000 adults were infected with HIV in India. This estimate is based upon a review of data provided by the National AIDS Control Organization. The methods to reach such estimate are succinctly reviewed and a series of scenarios presented.

Sexually transmitted disease services in Madras: could their role in AIDS prevention be strengthened?

A baseline evaluation of the quality of STD case management was conducted in five areas of Madras city in 1992, using HIV prevention indicators recommended by the World Health Organization. Eighty-four interviews and 108 observations of private and public clinic practitioners were conducted. Sixty-one percent of interviewed doctors reported making only specific "clinical" diagnoses and 17% reported making only the WHO recommended syndrome-based diagnoses while 22% reported making both types of diagnosis. The adequacy of treatment was compared against various standards, including the Indian National Guidelines for STD management. Almost half of the health care providers (HCP) reported using a treatment effective against the two main pathogens that may cause male urethritis, while 20% reported using a treatment that was not effective against either. For male ulcers only 12% of HCPs reported using treatment effective against both syphilis and chancroid. Seventy-nine percent of the HCP reported that they advised their patients to use condoms, but in 30% only of observed consultations, condoms were promoted for STD or HIV/AIDS prevention. As information concerning the relative prevalence of pathogens in different areas is unlikely to be available, there is an urgent need for the syndromic approach to STD treatment be adopted by health care providers.

Structured observations of hygiene behaviours in Burkina Faso: validity, variability, and utility

The use of observation techniques has been promoted for the study of hygiene practices; however, questions still remain about the validity and repeatability of such techniques. In this article we compare data on hygiene behaviours obtained from questionnaires with data obtained using a structured observation approach and examine the repeatability of structured observations of behaviours and spot observations of environmental conditions. Poor agreement between questionnaire responses and observations was found for child defecation and stool disposal practices (kappa statistic: 0.25 and 0.28, respectively). There was evidence of over-reporting of "good" behaviours (P < 0.0001). Repeated observations of child defecation and stool disposal behaviours showed better agreement (kappa statistic: 0.76 and 0.62, respectively) based on small sample sizes. These findings suggest that our questionnaire data are less valid than data obtained by direct observation. However, different approaches to questioning may be less prone to over-reporting of "good" behaviours than our approach. Further research into the validity of different forms of question is warranted. Behaviours and conditions related to hygiene vary. Observations may be useful in determining the frequency of different behaviours/conditions in the community. However, individual practices may be too variable to assign individuals to exposed and non-exposed groups for the purpose of identifying links with health outcomes. Further studies on the variability of behaviours and the repeatability of observations are therefore needed