Worm infections significantly increase the risk of HIV infection

Risk of HIV infection significantly increased by worm infections
Worm infections can be unremarkable for a long time, but sometimes they pose significant health risks. This also includes an increased risk of HIV infection - at least in the case of filariats, which are widespread in Africa. An international research team led by Professor Michael Hölscher and Dr. Ing. Inge Kroidl from the Ludwig-Maximillians-University (LMU) in Munich has identified worm infections as a possible cause of the particularly high prevalence of AIDS in the African population.

Since the onset of the HIV epidemic, LMU has "speculated as to why HIV and the AIDS-induced immunodeficiency syndrome (AIDS) are so much more prevalent in Africa than in other countries around the world." The international research team has now been tested in a cohort study identify infections with Wuchereria bancrofti, a common roundworm in Africa, as possible cause. The scientists have published their findings in the journal "The Lancet".

Infections with the roundworms of the genus Wuchereria bancrofti increase the risk of HIV infection. (Image: Dr_Kateryna / fotolia.com)

Cohort study in Tanzania
The researchers from the Tropical Institute of the LMU, the University of Bonn and the African partner institution of the German Center for Infection Research (DZIF) in Tanzania analyzed the data of around 18,000 persons from 2006 to 2011 from Tanzania as part of the cohort study. The original study was designed to identify HIV risk factors in the general population in southwestern Tanzania. For their current work, the researchers additionally examined a subgroup of 1,055 people for infection with roundworms (filariae).

Lymphatic filariasis episode of worm infection
The infection with the roundworm Wuchereria bancrofti causes a so-called lymphatic filariasis, a disease of the lymphatic vessels, which in the worst case leads to elephantiasis, according to the LMU. The drug combination used in Africa is only effective against the microfilaria produced by the worms, which migrate into the blood and are spread from there via mosquitoes. According to the researchers, the adult worm "often stays alive for years in the lymphatic system of the human body," reports the LMU. Here, he apparently also an increased HIV susceptibility.

Risk of HIV infection increased dramatically
Of the total of 32 new HIV infections among the subjects, a striking number were found in study participants who simultaneously showed a worm infection. "The comparison of Filaria infected with non-infected shows a significantly higher risk of HIV infection, which differs greatly depending on the age group," said the LMU. For the 14- to 25-year-olds, it had more than tripled and for the 25- to 45-year-olds more than doubled, the researchers explain. For over 45s, the risk was still increased by a factor of 1.2.

New therapies against worm infections required
"Especially affected are adolescents and young adults: Their risk of becoming infected with HIV increased about threefold if they were infected with Wuchereria bancrofti," said Inge Kroidl from the Department of Infectious Diseases and Tropical Medicine at LMU. According to Michael Hölscher, director of the tropical institute in Munich and initiator of the cohort studies, this initial confirmation of a long-cherished hypothesis, however, "only really starts the work." Above all, therapies are important, including the adult worms of W. bancrofti eliminate quickly, adds Professor Achim Hörauf from the Institute of Medical Microbiology, Immunology and Parasitology at the University Hospital Bonn. (Fp)