A 12-year study published in The Lancet HIV in May 2025 included researchers from LMU University Hospital in Munich and the National Institute for Medical Research in Mbeya. The RHINO study followed residents in Kyela district, Mbeya region, from 2007 to 2019 while health authorities rolled out anti-parasitic drugs in the community.
The researchers monitored 1,139 HIV-negative people in four groups. Among 848 people who never had the parasite there were 0.68 HIV cases per 100 people per year. Among 272 people who were infected but later cured there were 0.73 cases per 100 people per year. Among 15 people who remained chronically infected the rate was 1.5 cases per 100 people per year. The team concluded that clearing the parasite reduced susceptibility to HIV and built on a 2016 Lancet paper that reported a two- to threefold increase in HIV vulnerability with infection.
The RHINO programme is led by Inge Kroidl. Researchers suspect that adult worms cause chronic immune activation in the lymphatic system, which makes it easier for HIV to establish and replicate. The effect is especially visible among adolescents who often lack other HIV risk exposures. Despite these findings, neither Tanzanian authorities nor the WHO have integrated filariasis elimination into standard HIV prevention policies.
Public health scientist Ibrahim Simiyu said the results challenge the long-standing separation of neglected tropical disease and HIV programmes. The team notes that mass drug administration with ivermectin and albendazole already exists in many countries, so the HIV benefit would be a low-cost add-on. Researchers are testing for similar trends in other endemic countries, including Mozambique, and warn that gains could reverse if treatment coverage falls.
Difficult words
- parasite — organism that lives on or in another
- cure — remove a disease or make healthy againcured
- susceptibility — likelihood of being harmed or infected
- filariasis — tropical disease caused by parasitic worms
- elimination — complete removal of a disease from an area
- mass drug administration — giving medicines to many people in community
- endemic — commonly found in a particular area
- coverage — proportion of people receiving treatment
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Discussion questions
- How could adding filariasis treatment to HIV prevention help local communities?
- What problems might make it difficult to keep treatment coverage high in a region?
- Would you support mass drug administration in your community? Why or why not?
