Tweet
By Tamara Bhandari July 14, 2020
Chikungunya virus, once confined to the Eastern Hemisphere, has infected millions of people in the Americas since 2013, when mosquitoes carrying the virus were discovered in the Caribbean. About half of all people infected with chikungunya virus never show symptoms, while some develop fever and joint pain that lasts about a week, and 10% to 30% develop debilitating arthritis that persists for months or years.
Scientists have understood little about why the severity of the illness varies so widely. A study from researchers at Washington University School of Medicine in St. Louis indicates, in mice, that gut bacteria may play a role. The research shows that mice with faulty gut microbiomes were less able to control chikungunya virus infection. Further, giving the mice a single species of bacteria — or a chemical compound produced by that species — improved the mice’s immune responses, lowered levels of the virus in their blood and reduced the chances that a mosquito that fed on blood from infected mice would acquire the virus.
The findings, published July 14 in the journal Cell, suggest that a healthy microbiome could help reduce the chance of severe chikungunya disease and possibly even reduce community spread by disrupting the transmission of virus from person to mosquito to another person.
“In many viral diseases, only a subset of the people who get infected become symptomatic, and we don’t really understand why,” said senior author Michael S. Diamond, MD, PhD, the Herbert S. Gasser Professor of Medicine. “There might be things that happen during your lifetime that shape your immune system and influence whether you can stop the infection early and have minimal symptoms, or fail to stop it and develop severe disease. We found that when mice don’t have a healthy gut microbiome, not only do they get sicker, but mosquitoes that sample their blood are more likely to get infected. Promoting a healthy microbiome could be important not just for individuals who might get infected but for the whole community in breaking or reducing the cycle of transmission.”
The gut microbiome is the community of bacteria that live in the intestines. Gut bacteria metabolize and chemically modify some of the material that comes through the digestive tract, generating vitamins and other compounds as byproducts that then are absorbed by cells or other microbes, and help regulate inflammation and the body’s response to infection.
https://source.wustl.edu/2020/07/gut...viral-illness/