Areas of high HIV prevalence, known as 'hotspots', do not necessarily fuel the epidemic in the wider population, say researchers.
Hotspots are often targeted for intense HIV control interventions, including treatment and prevention, to maximize their effect and reach the people in greatest need first.
These strategies often assume that hotspots are also sources of disease transmission to other areas, and that targeting hotspots will have the added indirect benefit of reducing new HIV infections in the wider population.
However, a new study by an international team of researchers, led by scientists at Imperial College London and the Rakai Health Sciences Program in Uganda, suggests this is not necessarily the case. Instead, the research shows that some hotspots seed very few infections to neighboring communities and actually receive more infections from outside.
The study was carried out with 'hotspot' fishing communities on the shores of Lake Victoria in Uganda, where approximately 40 percent of the population are infected with HIV, amongst the highest HIV prevalence levels in the world. The team mapped how disease was transmitted between these communities and larger inland communities with much lower HIV prevalence.
Contrary to expectation, they found that more HIV infections were driven by the inland communities with lower HIV prevalence than by the HIV hotspots. The results are published today in Lancet HIV .
Lead researcher Dr Oliver Ratmann, from the Department of Mathematics at Imperial, said:
Our finding shows that HIV disease dynamics are not as obvious as they may seem, and advises caution against equating and stigmatizing hotspots as population groups that drive HIV spread in Africa."
Co-author of the study Dr Kate Grabowski, from the Johns Hopkins Bloomberg School of Public Health, added:
We were really surprised by the findings. Lake Victoria fishing communities have long been assumed to be drivers of transmission in neighboring East African communities; however, our results show that is likely not the case."
The team used recent advances in molecular biology and advanced statistics to map the transmission of HIV between people - the chain of infection events that lead to someone getting the disease. Related Stories
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