Taking the strain out of onchocerciasis? A reanalysis of blindness and transmission data does not support the existence of a savannah blinding strain of onchocerciasis in West Africa.

Onchocerciasis (also known as 'river blindness'), is a neglected tropical disease (NTD) caused by the (Simulium-transmitted) filarial nematode Onchocerca volvulus. The occurrence of 'blinding' (savannah) and non-blinding (forest) parasite strains and the existence of corresponding, locally adapted Onchocerca-Simulium complexes were postulated to explain greater blindness prevalence in savannah than in forest foci. As a result, the World Health Organization (WHO) Onchocerciasis Control Programme in West Africa (OCP) focused anti-vectorial and anti-parasitic interventions in savannah endemic areas. In this paper, village-level data on blindness prevalence, microfilarial prevalence, and transmission intensity (measured by the annual transmission potential, the number of infective, L3, larvae per person per year) were extracted from 16 West-Central Africa-based publications, and analysed according to habitat (forest, forest-savannah mosaic, savannah) to test the dichotomous strain hypothesis in relation to blindness. When adjusting for sample size, there were no statistically significant differences in blindness prevalence between the habitats (one-way ANOVA, P=0.68, mean prevalence for forest=1.76±0.37 (SE); mosaic=1.49±0.38; savannah=1.89±0.26). The well-known relationship between blindness prevalence and annual transmission potential for savannah habitats was confirmed and shown to hold for (but not to be statistically different from) forest foci (excluding data from southern Côte d'Ivoire, in which blindness prevalence was significantly lower than in other West African forest communities, but which had been the focus of studies leading to the strain-blindness hypothesis that was accepted by OCP planners). We conclude that the evidence for a savannah blinding onchocerciasis strain in simple contrast with a non-blinding forest strain is equivocal. A re-appraisal of the strain hypothesis to explain patterns of ocular disease is needed to improve understanding of onchocerciasis epidemiology and disease burden estimates in the light of the WHO 2030 goals for onchocerciasis.

Need for timely paediatric HIV treatment within primary health care in rural South Africa.

BACKGROUND: In areas where adult HIV prevalence has reached hyperendemic levels, many infants remain at risk of acquiring HIV infection. Timely access to care and treatment for HIV-infected infants and young children remains an important challenge. We explore the extent to which public sector roll-out has met the estimated need for paediatric treatment in a rural South African setting. METHODS: Local facility and population-based data were used to compare the number of HIV infected children accessing HAART before 2008, with estimates of those in need of treatment from a deterministic modeling approach. The impact of programmatic improvements on estimated numbers of children in need of treatment was assessed in sensitivity analyses. FINDINGS: In the primary health care programme of HIV treatment 346 children <16 years of age initiated HAART by 2008; 245(70.8%) were aged 10 years or younger, and only 2(<1%) under one year of age. Deterministic modeling predicted 2,561 HIV infected children aged 10 or younger to be alive within the area, of whom at least 521(20.3%) would have required immediate treatment. Were extended PMTCT uptake to reach 100% coverage, the annual number of infected infants could be reduced by 49.2%. CONCLUSION: Despite progress in delivering decentralized HIV services to a rural sub-district in South Africa, substantial unmet need for treatment remains. In a local setting, very few children were initiated on treatment under 1 year of age and steps have now been taken to successfully improve early diagnosis and referral of infected infants.

Intervention to promote exclusive breast-feeding for the first 6 months of life in a high HIV prevalence area.

OBJECTIVES: We report on a nonrandomized intervention cohort study to increase exclusive breast-feeding rates for 6 months after delivery in HIV-positive and HIV-negative women in KwaZulu-Natal, South Africa. METHODS: Lay counselors visited women to support exclusive breast-feeding: four times antenatally, four times in the first 2 weeks postpartum and then fortnightly to 6 months. Daily feeding practices were collected at weekly intervals by separate field workers. Cumulative exclusive breast-feeding rates from birth were assessed by Kaplan-Meier analysis and association with maternal and infant variables was quantified in a Cox regression analysis. FINDINGS: One thousand, two hundred and nineteen infants of HIV-negative and 1217 infants of HIV-positive women were followed postnatally. Median duration of exclusive breast-feeding was 177 (R = 1-180; interquartile range: 150-180) and 175 days (R = 1-180; interquartile range: 137-180) in HIV-negative and HIV-positive women, respectively. Using 24-h recall, exclusive breast-feeding rates at 3 and 5 months were 83.1 and 76.5%, respectively, in HIV-negative women and 72.5 and 66.7%, respectively, in HIV-positive women. Using the most stringent cumulative data, 45% of HIV-negative and 40% of HIV-positive women adhered to exclusive breast-feeding for 6 months. Counseling visits were strongly associated with adherence to cumulative exclusive breast-feeding at 4 months, those who had received the scheduled number of visits were more than twice as likely to still be exclusively breast-feeding than those who had not (HIV-negative women: adjusted odds ratio: 2.07, 95% confidence interval: 1.56-2.74, P < 0.0001; HIV-positive women: adjusted odds ratio: 2.86, 95% CI 2.13-3.83, P < 0.0001). CONCLUSION: It is feasible to promote and sustain exclusive breast-feeding for 6 months in both HIV-positive and HIV-negative women, with home support from well trained lay counselors.