Emergence of new HIV-1 subtypes other than Subtype C among antenatal women in Lusaka, Zambia.

Molecular epidemiology of HIV-1 in Zambia was investigated by direct sequencing of PCR products from samples collected from antenatal attendees in Lusaka, Zambia. One hundred and forty samples were initially screened for HIV, using antibody assays. Thirty-three (23.6%) samples were HIV-1 positive. Sequences of the HIV-1 env gp120 region were obtained from 28 of 33 (85%) HIV-1-positive samples. Twenty-six of the 28 sequences were HIV-1 env subtype C-like as previously reported. However, one HIV-1 env subtype D-like virus and one HIV-1 env subtype G-like virus were identified. This is the first time that these two HIV-1 env subtype viruses have been identified in Zambia, suggesting that more subtypes could be in existence.

Declining HIV prevalence and risk behaviours in Zambia: evidence from surveillance and population-based surveys.

OBJECTIVE: To examine trends in HIV prevalence and behaviours in Zambia during the 1990s. METHODS: The core Zambian system for epidemiological surveillance and research has two major components: (i) HIV sentinel surveillance at selected antenatal clinics (ANC) in all provinces; and (ii) population-based HIV surveys in selected sentinel populations (1996 and 1999). The former was refined in 1994 to improve the monitoring of prevalence trends, whereas the latter was designed to validate ANC-based data, to study change in prevalence and behaviour concomitantly and to assess demographic impacts. RESULTS: The ANC-based data showed a dominant trend of significant declines in HIV prevalence in the 15--19 years age-group, and for urban sites also in age-group 20--24 years and overall when rates were adjusted for over-representation of women with low education. In the general population prevalence declined significantly in urban women aged 15--29 years whereas it showed a tendency to decline among rural women aged 15-24 years. Prominent decline in prevalence was associated with higher education, stable or rising prevalence with low education. There was evidence in urban populations of increased condom use, decline in multiple sexual partners and, among younger women, delayed age at first birth. CONCLUSIONS: The results suggested a dominant declining trend in HIV prevalence that corresponds to declines in incidence since the early 1990s attributable to behavioural changes. Efforts to sustain the ongoing process of change in the well-educated segments of the population should not be undervalued, but the modest change in behaviour identified among the most deprived groups represents the major preventive challenge.

Studying dynamics of the HIV epidemic: population-based data compared with sentinel surveillance in Zambia.

OBJECTIVES: To establish population-based HIV survey data in selected populations, and to assess the validity of extrapolation from HIV sentinel surveillance amongst antenatal clinic attenders (ANC) to the general population. METHODS: In a population survey, adults aged > or = 15 years were selected by stratified random cluster sampling (n = 4195). The survey was carried out in catchment populations of clinics used for national HIV surveillance. The methodology allows detailed comparisons of HIV infection patterns to be made in two areas (urban and rural). Whereas the sentinel surveillance used serum-based HIV testing, the population survey used saliva (93.5% consented to provide a saliva sample). RESULTS: Surveillance of ANC tended to underestimate the overall HIV prevalence of the general population, but differences were not statistically significant. In the urban area, the adjusted overall HIV prevalence rate of ANC (aged 15-39 years) was 24.4% [95% confidence interval (CI), 20.9-28.0] compared with 26.0% (95% CI, 23.4-28.6) in the general population. The respective rural estimates were 12.5% (95% CI, 9.3-15.6) versus 16.4% (95% CI, 12.1-20.6). Age-specific prevalence rates showed ANC to overestimate infection in teenagers (aged 15-19 years), whereas in the reverse direction of those aged > or = 30 years. Teenagers analysed by single year of age revealed both ANC and women in the general population with about the same steep increase in prevalence by age, but the former at consistently higher rates. Extrapolations might be biased substantially due to the higher pregnancy rates amongst uninfected individuals. CONCLUSIONS: ANC-based data might draw a rather distorted picture of current dynamics of the HIV epidemic. Even though representing an obvious oversimplification, extrapolations of overall prevalence rates may correlate with that of the general population.

PIP: Assessments of the dynamics of the HIV/AIDS epidemic in Africa are based largely on sentinel surveillance of antenatal clinic (ANC) attenders. The validity of use of this key sentinel group in terms of HIV prevalence estimation was evaluated in a population-based survey of 4195 Zambian adults recruited through stratified random cluster sampling in urban Lusaka and rural Mposhi district in 1995-96. The survey was carried out in catchment populations of clinics used for national HIV surveillance. Overall, ANC surveillance tended to underestimate HIV prevalence in the general population, but differences were not statistically significant in either the urban or the rural area. In Lusaka, the adjusted overall HIV prevalence among ANC attenders was 24.4% compared with 26.0% in the population-based survey. The rural estimates were 12.5% and 16.4%, respectively. Comparison of age-specific prevalences indicated ANC overestimated infection in teenagers and underestimated HIV in those aged 30 years and over. Prevalence rates increased steeply by age, at comparable increment levels among women in both samples, while men had stable prevalence rates by age. These findings suggest that extrapolations from surveillance data may indeed produce a distorted picture of the current dynamics of the HIV epidemic in the population at large. Women with higher educational attainment are underrepresented in the ANC surveys. The higher pregnancy and birth rates among HIV-negative compared to HIV-positive women is another potential source of bias, as is the high rate of ANC clients aged 18-19 years (66%, compared with 34% in the general population of women). Information on single year of age, educational level, and residence should be collected in sentinel surveillance systems to allow appropriate stratification. Since HIV prevalence in young people may be the most reliable marker of changes in incidence, sample size increases in the 15-19 year age group should be considered.

Understanding lay perspectives: care options for STD treatment in Lusaka, Zambia.

Understanding lay persons' perceptions of STD care is critical in the design and implementation of appropriate health services. Using 20 unstructured group interviews, 10 focus group discussions and 4 STD case simulations in selected sub-populations in Lusaka, we investigated lay person perspectives of STD services. The study revealed a large diversity of care options for STD in the communities, including self-care, traditional healers, medicine sold in the markets and streets, injections administered in the compounds, private clinics, health centres and hospital. The factors identified as influencing care seeking behaviour are: lay referral mechanisms, social cost, availability of care options, economics, beliefs, stigma and quality of care as perceived by the users.

PIP: Lusaka's health system is comprised of 4 hospitals, 22 government urban health centers, 144 private for-profit clinics, and more than 1000 traditional healers and traditional birth attendants. The authors explored laypeople's perspectives of sexually transmitted disease (STD) care services using 20 unstructured group interviews, 10 focus group discussions, and 4 STD case simulations in selected subpopulations of the city. People of differing age and sex were sampled. A large diversity of care options for STD was found in the communities, including self-care, traditional healers, medicine sold in the markets and streets, and injections administered in the compounds, private clinics, health centers, and hospitals. Lay referral mechanisms, social cost, the availability of care options, economics, beliefs, stigma, and the quality of care as perceived by users influence care-seeking behavior in this population.

HIV in Zambia: myth or monster?

Despite attempts by a few journalists to portray the spread of AIDS in African countries as fictitious, the situation in Zambia shows that such views are completely misguided.