High HIV prevalence in a southern semi-rural area of Mozambique: a community-based survey.

BACKGROUND: Southern African countries have borne the brunt of the HIV/AIDS pandemic. Monitoring epidemiological dynamics is critical to identify the populations at greatest risk of infection and to guide control strategies. METHODS: A cross-sectional community-based study to determine age- and sex-specific HIV prevalence among individuals aged 18-47 years was carried out in Manhiça, southern Mozambique. Participants were randomly selected from the demographic surveillance system in place in the area and voluntary HIV counselling and testing were offered at home. In addition, HIV prevalence estimates from the antenatal clinic (ANC) were collected prospectively. RESULTS: A total of 839 individuals were invited to participate in the study. Of these, 722 were recruited (50.7% women). The overall HIV prevalence in the community was 39.9% [95% confidence interval (CI) 35.9-43.8%]. By age, the prevalence was 23.2% (95% CI 17.9-28.6%) in individuals aged 18-27 years, 41.2% (95% CI 35.6-48.3%) in those aged 28-37 years and 44.8% (95% CI 38.4-51.2%) in those aged 38-47 years. HIV prevalence was higher among women than men in all age groups. The overall HIV prevalence estimate for women in the community (43.1%; 95% CI 37.6-48.5%) was 1.4 times higher than that for those attending the ANC (29.4%; 95% CI 26.7-32.0%). CONCLUSIONS: The high HIV prevalence found in this region suggests that the epidemic is in a mature stable phase. The lower rates in the ANC than in the community suggest that ANC evaluations may underestimate community HIV prevalence. Resources to monitor HIV infection dynamics are needed to guide targeted control strategies in countries in which the epidemic exacts the greatest toll.

High HIV prevalence in a southern semi-rural area of Mozambique: a community-based survey

Background: Southern African countries have borne the brunt of the HIV/AIDS pandemic. Monitoring epidemiological dynamics is critical to identify the populations at greatest risk of infection and to guide control strategies. Methods: A cross-sectional community-based study to determine age- and sex-specific HIV prevalence among individuals aged 18-47 years was carried out in Manhiça, southern Mozambique. Participants were randomly selected from the demographic surveillance system in place in the area and voluntary HIV counselling and testing were offered at home. In addition, HIV prevalence estimates from the antenatal clinic (ANC) were collected prospectively. Results: A total of 839 individuals were invited to participate in the study. Of these, 722 were recruited (50.7% women). The overall HIV prevalence in the community was 39.9% [95% confidence interval (CI) 35.9-43.8%]. By age, the prevalence was 23.2% (95% CI 17.9-28.6%) in individuals aged 18-27 years, 41.2% (95% CI 35.6-48.3%) in those aged 28-37 years and 44.8% (95% CI 38.4-51.2%) in those aged 38-47 years. HIV prevalence was higher among women than men in all age groups. The overall HIV prevalence estimate for women in the community (43.1%; 95% CI 37.6-48.5%) was 1.4 times higher than that for those attending the ANC (29.4%; 95% CI 26.7-32.0%). Conclusions: The high HIV prevalence found in this region suggests that the epidemic is in a mature stable phase. The lower rates in the ANC than in the community suggest that ANC evaluations may underestimate community HIV prevalence. Resources to monitor HIV infection dynamics are needed to guide targeted control strategies in countries in which the epidemic exacts the greatest toll.

Stabilization of HIV incidence in women of reproductive age in southern Mozambique.

INTRODUCTION: The collection of incidence data on HIV infection is necessary to evaluate the status and dynamics of the epidemic and the effectiveness of intervention strategies. However, this is usually difficult in low-income countries. METHODS: Five yearly point HIV prevalence estimations (in 1999, 2003, 2004, 2005 and 2008) were obtained for women between 15 and 45 years of age participating in three studies carried out for other purposes at the Antenatal Clinic (ANC) in Manhiça, Mozambique. HIV incidence was estimated between prevalence points using a previously validated methodology. Two methods were used, one based on mortality rates for three HIV epidemic scenarios, and the other based on survival information after infection. The pattern over time was captured by fitting a log-regression model. RESULTS: The prevalence of HIV infection ranged from 12% in 1999 to 49% in 2008. The HIV incidence increased from approximately 3.5 cases per 100 person-years in 2001 to 14 per 100 person-years in 2004, with stabilization thereafter to levels of around 12 cases per 100 person-years. The incidence estimates were comparable for the two methods used. CONCLUSION: These findings indicate an increase in the prevalence and incidence of HIV infection among women of reproductive age over the 9 years of the analysis, with a plateau in the incidence of infection since 2005. However, the very high figures for both prevalence and incidence highlight the importance of the continuation of the prevention and treatment programmes that already exist, and suggest that implementation of preventive measures is needed in this area.

Estimating the vaccine-preventable burden of hospitalized pneumonia among young Mozambican children.

Polysaccharide-protein conjugate vaccines against Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae have proven efficacy against radiologically confirmed pneumonia. Measurement of pneumonia incidence provides a platform to estimate of the vaccine-preventable burden. Over 24 months, we conducted surveillance for radiologically confirmed severe pneumonia episodes among children <2 years of age admitted to a rural hospital in Manhiça, southern Mozambique. Study children were tested for HIV during the second year of surveillance. Severe pneumonia accounted for 15% of 5132 hospital admissions and 32% of in-hospital mortality among children <2 years of age. Also, 43% of chest radiographs were interpreted as radiologically confirmed pneumonia. HIV-infection was associated with 81% of fatal pneumonia episodes among children tested for HIV. The minimum incidence rate of radiologically confirmed pneumonia requiring hospitalization was 19 episodes/1000 child-years. Incidence rates among HIV-infected children were 9.3-19.0-fold higher than HIV-uninfected. Introduction of Hib and pneumococcal conjugate vaccines would have a substantial impact on pneumonia hospitalizations among African children if vaccine effects are similar to those observed in clinical trials.

Human immunology of measles virus infection.

Measles is a highly contagious disease, which was responsible for high infant mortality before the advent of an effective vaccine in 1963. In immunocompetent individuals, measles virus (MV) infection triggers an effective immune response that starts with innate responses and then leads to successful adaptive immunity, including cell-mediated immunity and humoral immunity. The virus is cleared and lifelong protection is acquired. However, changing epidemiology of measles due to vaccination as well as severe immunodeficiency has created new pockets of individuals vulnerable to measles. This chapter reviews the knowledge on effective measles-specific immune responses induced by natural infection and vaccination and explores problems arising in specific cases of immunodeficiency, infant immunity, and ineffective vaccination against measles.

Mother-to-child transmission of HIV-1: association with malaria prevention, anaemia and placental malaria.

OBJECTIVES: Malaria infection may impact on mother-to-child transmission (MTCT) of HIV-1. Prevention of malaria in pregnancy could thus potentially affect MTCT of HIV. We studied the impact of intermittent preventive treatment during pregnancy (IPTp) on HIV-1 MTCT in southern Mozambique. METHODS: A total of 207 HIV-positive Mozambican pregnant women were enrolled in the study as part of a randomized placebo-controlled trial of two-dose sulfadoxine-pyrimethamine (SP) IPTp in women receiving single-dose nevirapine to prevent MTCT of HIV. HIV RNA viral load, maternal anaemia and peripheral and placental malaria were assessed at delivery. Infant HIV status was determined by DNA polymerase chain reaction (PCR) at 1 month of age. RESULTS: There were 19 transmissions of HIV in 153 mother-infant pairs. IPTp with SP did not have a significant impact on MTCT (11.8% in the SP group vs. 13.2% in the placebo group; P=0.784) or on maternal HIV RNA viral load [16 312 (interquartile range {IQR} 4076-69 296) HIV-1 RNA copies/mL in the SP group vs. 18 274 (IQR 5471-74 104) copies/mL in the placebo group; P=0.715]. In multivariate analysis, maternal HIV RNA viral load [adjusted odds ratio (AOR) 19.9; 95% confidence interval (CI) 2.3-172; P=0.006] and anaemia (haematocrit <33%; AOR 7.5; 95% CI 1.7-32.4; P=0.007) were independent risk factors for MTCT. Placental malaria was associated with a decrease in MTCT (AOR 0.23; 95% CI 0.06-0.89; P=0.034). CONCLUSIONS: IPTp with SP was not associated with a significant impact on MTCT of HIV. Maternal anaemia was an independent risk factor for MTCT.

Generalized immunosuppression: how viruses undermine the immune response.

Following infection, a virus must battle against the host's immune response. Viruses have developed many ways to escape immune surveillance and downregulate the host's immune response. Some viruses cause a generalized immunosuppression, thereby inhibiting or depressing the immune response towards themselves as well as towards unrelated pathogens. This review will focus on the mechanisms involved in the three main human viral infections causing immunosuppression: measles, human immunodeficiency virus and cytomegalovirus. We will also discuss what has been learned from the extensively studied mouse models of viral-induced immunosuppression: lymphocytic choriomeningitis virus and Rauscher leukemia virus. All of these viruses that induce generalized immunosuppression appear to do so by very similar mechanisms. They hinder antigen presentation to T cells and/or hematopoiesis. We will highlight the similarities in the viral targets as well as present evidence for alternate mechanisms.