Risk of HIV infection from worm infections increases significantly
Worm infections can be inconspicuous for a long time, but they can pose significant health risks. This also includes an increased risk of HIV infection - at least among the filariasis pathogens that are widespread in Africa. An international team of researchers led by Professor Michael Hölscher and Dr. Inge Kroidl from the Ludwig Maximillians University (LMU) in Munich has identified the worm infections as a possible cause of the particularly widespread spread of AIDS in the African population.
Since the start of the HIV epidemic, according to the LMU, "speculation has been made as to why HIV and the virus-induced immune deficiency disease AIDS are so much more widespread in Africa than in other countries around the world." The international research team has now been able to conduct a cohort study identify the infections with Wuchereria bancrofti, a roundworm common in Africa, as a possible cause. The scientists have published their results in the specialist journal "The Lancet".
Cohort study in Tanzania
The researchers from the Tropical Institute of 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 people from Tanzania from 2006 to 2011 as part of the cohort study. The original study was designed to determine HIV risk factors in the general population in southwest Tanzania. For their current work, the researchers also examined a subgroup of 1,055 people for an infection with roundworms (filaria).
Lymphatic filariasis as a result 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 microfilariae produced by the worms, which migrate into the blood and from there are spread via mosquitoes. The adult worm, on the other hand, remains, according to the researchers, "often alive in the lymphatic system of the human body for years," reports the LMU. Here he apparently also causes an increased susceptibility to HIV.
Risk of HIV infection increases dramatically
Of the 32 new HIV infections that occurred in the test subjects, a striking number were found in study participants who also showed a worm infection. "The comparison of filaria infected with uninfected shows a significantly higher risk of HIV infection, which differs greatly depending on the age group," said the LMU. The researchers said that it was more than threefold higher for 14- to 25-year-olds and more than double for 25- to 45-year-olds. The risk for those over 45 was still increased by a factor of 1.2.
New therapies against worm infections are required
"Adolescents and young adults are particularly affected: Their risk of contracting HIV increased about three times if they were infected with Wuchereria bancrofti," said Inge Kroidl from the Infectious Diseases and Tropical Medicine Department at LMU. According to Michael Hölscher, head of the Tropical Institute in Munich and initiator of the cohort studies, with this first confirmation of a long-held hypothesis, the work "is only really getting started." Above all, therapies are now important, which are also 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)