Figuring out how to stop fleas from vomiting their food could be a key to stopping the transmission of deadly diseases such as bubonic plague.

At the Paul G. Allen Center for Global Health at Washington State University, Professor Viveka Vadyvaloo is exploring ways to stop the transmission of bubonic plague through flea vomit, starting with studying a globe bacteria inside the flea’s throat.

It’s that globe of bacteria, Yersinia pestis, held together by a sticky biofilm, which causes fleas to vomit their blood meal into their host, thereby facilitating the transmission of plague and other diseases.

“You can imagine, you have something stuck in your throat and you try to get some water but you can’t. You’re going to throw up all that water, and that’s what happens to the flea, ”Vadyvaloo said. “The stranded and hungry flea will repeatedly bite its rodent or human host, creating more possibilities for infection by regurgitating blood containing the plague bacteria dislodged from the biofilm at the bite site.”

The plague is best known for causing “the black plague” in the mid-1300s in Europe and Asia, which killed some 50 million people. However, the disease is also responsible for two other pandemics, the most recent in the 1890s in Asia. The disease can still be found in wild rodent populations of the American West, particularly in Arizona, New Mexico and Colorado. It is more common in parts of the Democratic Republic of the Congo, Madagascar, Mongolia, Peru and several other countries.

While humans rarely contract the disease, a Wyoming woman was infected last month according to the Wyoming Department of Health.

According to research conducted in Vadyvaloo’s lab recently published in the journal American Society for Microbiology, mBio, a protein called CsrA is essential for producing the biofilm that causes fleas to vomit into their host. It also prevents another protein – Hfq – from stopping this production.

“This protein – CsrA – is able to stop the production of this other protein that usually stops bacteria from making this biofilm,” Vadyvaloo said.

In the lab, Vadyvaloo was assisted by former graduate student Amelia Silva-Rowher, the first author of the article.

Their research shows that biofilm production was significantly reduced in the absence of CsrA.

“We know relatively little about how the bacteria interact with the host chip,” Vadyvaloo said. “This puts into perspective some of the molecular processes that are essential for the formation of this biofilm.”

While all forms of plague can now be treated with antibiotics, Vadyvaloo said understanding the basic science of how bacteria form the biofilm in the chip will allow researchers to examine solutions to reduce or end the disease. transmission for good.

“Our work could eventually lead to something as simple as a cream applied as a repellant that would prevent the creation of the biofilm in the flea stomach, but we have a lot more to understand before this is possible,” she declared.