Think a tiny parasitic worm has nothing to do with HIV? Researchers have discovered that infection with Wuchereria bancrofti, a thread-like parasite responsible for lymphatic filariasis, increases the risk of contracting HIV, and tackling these worms could help reduce new HIV infections.
Lymphatic filariasis is a tropical mosquito-borne disease that affects the lymphatic system, leading to swelling in the legs and other parts of the body. While most people infected with the worms causing lymphatic filariasis show no symptoms, those who do may experience severe swelling (elephantiasis), hydrocele (fluid accumulation around the testicle), skin thickening, respiratory issues, and bacterial infections, often appearing years after infection.
In a groundbreaking study conducted in Tanzania, researchers uncovered a significant connection between the Wuchereria bancrofti worm and an increased risk of contracting HIV. This discovery is gaining further attention, as a follow-up research published in the Lancet HIV has further confirmed that addressing this worm infection not only curbs its effects but also contributes to a reduction in new HIV cases.
Between 2009 and 2015, as Tanzania rolled out a nationwide deworming program, researchers launched the RHINO study (Risk of HIV Infections through Nematode Organisms) to explore whether eliminating Wuchereria bancrofti could reduce HIV risk. In 2019, they followed up with 1,139 participants in Kyela, Tanzania, aged 14 to 65, dividing them into three groups based on their worm infection status: currently infected, previously cured, or never infected.
The findings offer a striking insight: among participants who were successfully treated for the parasitic worm, new HIV infections dropped by nearly 60%, a statistically significant result even after accounting for age and gender differences. Meanwhile, those who had never been infected with the parasite showed no change in HIV rates over the same period. This sharp contrast strongly suggests that clearing the worm infection may play a direct role in reducing HIV susceptibility.
Researchers now plan to delve deeper to uncover the immunological mechanisms that might explain how the parasite increases susceptibility to HIV transmission, a mystery that could open new doors in the fight against both infections.
“Our findings open up new possibilities for the prevention of HIV in affected regions. The therapy to combat lymphatic filariasis is still not optimal. We are therefore continuing to research this topic and hope to bring at least a few of the drugs developed also with DZIF (German Center for Infection Research) funding, to registration,” said Prof. Achim Hörauf, co-author of the study, in a news release.
