Worm infections make African women more vulnerable to STIs
An international study conducted by the University of Cape Town and involving Benjamin G. Dewals, FNRS Research associate in the FARAH Research Unit (Faculty of Veterinary Medicine) at ULiège, shows that intestinal worm infections can make African women more vulnerable to sexually transmitted infections (STIs). The study was conducted by Dr Alisha Chetty and Prof William Horsnell and published in Cell Host & Microbe.
P
arasitic worm (helminth) infections are a widespread health and economic problem worldwide. Despite this, the impact of helminth infections on the pathogenesis of other types of infections remains poorly studied. In particular, the way in which helminth infections modify common viral infections in areas where they are endemic is poorly understood. Recently, more and more scientists are asking how helminthic infections affect host immunity to other pathogens.
A study lead by researchers from the Universities of Cape Town and Birmingham, involving experts from Germany, Norway, Belgium, France and Togo, looked at intestinal worm infections in women in sub-Saharan Africa and their impact on the propensity to contract and develop sexually transmitted infections (STIs). This region is known to have a very high rate and severity of worm infections, which, when colonizing the gut, can alter immunity in other parts of the body.
The researchers found that infection with an intestinal worm could alter vaginal immunity and thus increase the likelihood of infection with herpes simplex virus type 2 (HSV-2) - the cause of genital herpes. They were also able to demonstrate that infection with intestinal worms increased the epithelial damage and pathology associated with genital herpesvirus infection, which can lead to severe necrosis of the vaginal tissue.
However, the researchers also found that they could prevent these worm-induced changes in the pathology of HSV-2 infection by targeting particular immune cells, the eosinophils. This finding suggests that in particular cases, this condition could be prevented or reduced using existing drugs," explains Benjamin G. Dewals, a researcher at FARAH (Faculty of Veterinary Medicine) at ULiège who participated in the study.
The researchers' work has identified for the first time how a worm infection can influence the rate and severity of a very important viral STI. These results help explain why STIs are more virulent in areas where worm infections are common.
Depletion of eosinophils rescues HSV-2 pathology in co-infected mice. Immunofluorescence analysis of day 6 post-HSV-2 vaginal tissue. White boxes indicate magnified sections.
Scientific reference
Chetty A., Darby M.G., Vornewald P.M., Martín-Alonso M., Filz A., Ritter M., McSorley H.J., Masson L., Smith K., Brombacher F., O’Shea M.K., Cunningham A.F., Ryffel B., Oudhoff M.J, Dewals B.G., Layland L.E., Horsnell W.G.C., Il4ra-independent vaginal eosinophil accumulation following helminth infection exacerbates epithelial ulcerative pathology of HSV-2 infection, Cell Host & Microbe, Volume 29, Issue 4, 14 April 2021, Pages 579-593.e5
