Worm Infection Linked to Increased HIV Risk

The parasitic worm Wuchereria bancrofti, primarily found in tropical regions of Africa and Asia, is known to cause lymphatic filariasis, a condition that can severely damage the lymphatic system and lead to significant swelling of the limbs.

Recent findings from a study conducted by the LMU University Hospital in Munich reveal that infection with this particular worm may significantly elevate the risk of contracting HIV. The initial Emini Study, conducted several years ago, indicated a notable correlation between W. bancrofti infection and increased HIV infection rates. Data collected between 2007 and 2011 showed that individuals infected with the worm experienced an HIV infection rate of 1.72 cases per 100 person-years, compared to just 0.69 cases per 100 person-years among those uninfected by the worm.

As part of a government initiative aimed at eliminating lymphatic filariasis, individuals in Tanzania received annual treatment with antihelminthic medications from 2009 to 2015. In 2019, researchers invited participants from one of the original Emini Study sites to partake in a follow-up study. A total of 1,139 participants, aged 14 to 65, were tested for both HIV and W. bancrofti, and they were categorized into three groups: those currently infected with the worm, those previously infected but now cured, and those never infected.

The analysis of HIV incidence between the two study periods--2007 to 2011 and 2011 to 2019--yielded significant results. The group that had been cured of W. bancrofti demonstrated a remarkable 60% reduction in HIV incidence, a finding that remained statistically significant even after adjusting for age and gender. In contrast, the group that had never been infected with the worm showed no changes in HIV incidence across the study periods. These findings have been published in the esteemed journal The Lancet HIV.

The lead researcher from the Tropical Institute at LMU concluded that the study supports the hypothesis that W. bancrofti infection plays a role in increasing the incidence of HIV. Consequently, efforts to combat W. bancrofti could help reduce the rates of new HIV infections.

Additionally, the director of the Tropical Institute emphasized that helminth infections, including W. bancrofti, are known to elevate the risk of HIV infection. Ongoing research seeks to uncover the immunological mechanisms that may explain this heightened susceptibility to HIV transmission associated with W. bancrofti. The implications of these findings might also pave the way for new strategies in HIV prevention in affected regions.