New research shows that parasitic nematodes, responsible for infecting more than a billion people globally, carry viruses that may solve the puzzle of why some cause serious diseases.
The findings are published in Nature Microbiology in an article titled, “Diverse RNA viruses of parasitic nematodes can elicit antibody responses in vertebrate hosts.”
A new study led by the Liverpool School of Tropical Medicine (LSTM) used bioinformatic data mining techniques to identify 91 RNA viruses in 28 species of parasitic nematodes, representing 70% of those that infect people and animals.
Nematode worms are the most abundant animals on the planet, with several species infecting humans as well as agriculturally and economically important animals and crops. However, scientists do not know how some nematodes cause certain diseases.
The new study opens the door to further study of whether these newly discovered viruses, only five of which were previously known to science, could contribute to many chronic, debilitating conditions.
Mark Taylor, PhD, professor of parasitology at LSTM, said: “This is a truly exciting discovery and could change our understanding of the millions of infections caused by parasitic nematodes.
“This raises the question of whether any of the diseases that these parasites are responsible for could be driven by the virus rather than directly by the parasitic nematode.”
The study authors propose that these newly identified viruses may play a role in some of these conditions. For example, onchocerciasis-associated epilepsy (OAE) that occurs in children and adolescents in Sub-Saharan Africa has recently been associated with onchocerciasis, but it is not known why this causes neurological symptoms such as uncontrollable repeated head nodding, as well as severe stunting, delayed puberty, and impaired mental health.
One of the viruses in the parasites that cause onchocerciasis identified in the new study is a rhabdovirus, the type that causes rabies. The authors of the study suggest that if this virus is infecting or damaging human nerve or brain tissue, that could explain the symptoms of OAE.
The illuminating discovery of these widespread yet previously hidden viruses was first made by Shannon Quek, PhD, a postdoctoral research associate at LSTM and lead author of the new study, who had initially been using the same data mining method to screen for viruses within mosquitoes that spread disease, before deciding to investigate nematodes.
“There are a lot of studies about the microbiomes of mosquitoes, and how the bacteria that live inside can block the spread of viruses, which might stop vector-borne diseases like dengue. This interplay between organisms in the same host led me to think—what else might be inside parasitic nematodes as well? Which after my discovery will now be the focus of our research.”
