The history of sub-Saharan Africa has been defined and determined to a large extent by the struggle against tropical diseases, many of them vector borne, including malaria, leishmaniasis, trypanosomiasis and many others. To add to this burden our continent has now to deal with the ravages of HIV and the consequent rise in tuberculosis. In this issue of the SACEMA Quarterly we discuss some of the key problems and ways in which we might be able to address and mitigate some of the challenges that we face in this regard.
This article reports on the role of the community health worker (CHW) and the Primary Health Care Re-engineering Model. CHWs are well placed to strengthen service delivery, build links for different government departments in the community, and be linkages for patients to access health care as well as other support systems. The CHW provides on-the-ground support to the patient/community member and links them to health and social service departments. The passion of the CHWs to help their community is valuable and should be supported and nurtured. The CHW is a valuable resource for the development and maintenance of the South African public health system. For linkage to care in health service delivery to be effective and sustainable, the support, guidance, and development of this cadre of worker is essential.
The use of laboratory assays to identify recent infections among samples collected in cross-sectional surveys provides a potentially powerful way to measure HIV incidence. Ongoing evaluations of candidate laboratory assays have highlighted improvements and shortcomings of individual assays in correctly identifying and classifying people as recently infected. We tested two candidate assays, Sedia Limiting Antigen (LAg) and BioRad avidity assays (BioRad) against samples from a prospective cohort study in which incidence was measured directly. BioRad and LAg avidity assays have false recent rates that are up to 8 times lower than those for the BED assay, providing the potential for improved estimates of HIV incidence.
This article is based on the presentation given by John Hargrove at the NRF Science for Society Lecture entitled Ending HIV/AIDS in South Africa held on 1 December 2016 in Stellenbosch. He argues that the proactive use of ART (Treatment as Prevention or TasP) provides a powerful weapon for combatting the HIV epidemic, and that we also have the tools for monitoring and evaluating the progress of that programme. Mathematical modelling has played an important role, both in suggesting appropriate interventions, and in developing new monitoring methods, but we are still in for a long journey.
Despite the importance of youth sexual behaviour for sexual and reproductive health and the severity of the HIV/AIDS there is relatively little empirical research on factors affecting the age at sexual debut in South Africa. In my dissertation I used survival analysis techniques to identify significant predictors of early sexual debut in a South African context. The results may assist in devising strategies and action plans to be used to educate adolescents in making informed and safe decisions regarding sexual debut.
We conducted surveys of travellers and their movement patterns in Mali, Burkina Faso, Zambia and Tanzania. We found that women travelling with children are a consistent group of relevance to malaria transmission. Our study also highlighted youth workers as a key traveller group of relevance to parasite dispersal in Mali.
The objective of my thesis was to develop a novel, parameterised mechanistic mathematical model which describes the dynamics of parasite invasion during the initial stages of malarial infection.
Juliet Pulliam has recently taken over from Alex Welte as director of SACEMA. In this issue, she reflects on the challenges – and many exciting opportunities – ahead.
The World Health Organization’s most recent guideline for the treatment of HIV recommends ART for all individuals living with HIV. Although this new recommendation is gaining traction among wealthier countries, many countries have not yet adopted this guideline. Instead, those countries follow a strategy of providing ART only to people with low CD4+ T-cell counts, which was necessary early in the HIV epidemic, but it is unclear whether the use of CD4 counts was based on sound science and logic.
Effective HIV prevention requires knowledge of the structure and dynamics of the social networks across which infections are transmitted. These networks are most commonly comprised of chains of sexual relationships. Whereas network data have long been collected during survey interviews, new data sources have become increasingly common in recent years. In this article, we review current and emerging methods for collecting HIV-related network data, as well as modelling frameworks commonly used to infer network parameters and map potential HIV transmission pathways within the network.