Research: Saliva protects body from traveler’s diarrhea

March 8 (UPI) — A protein found in saliva helps protects the body from traveler’s diarrhea, which may lead to the development of new preventive therapies for the disorder and others, according to a study.

Researchers at Boston University School of Medicine and collaborators found the protein histatin-5 in human saliva helps the body defend itself from gut infections, according to findings published Thursday in the Journal of Infectious Diseases.

Travelers’ diarrhea is a common illness affecting up to 70 percent of travelers, according to the Centers for Disease Control and Prevention. But besides being an inconvenience, thousands of deaths are linked to the bacterial disease. The pili, or appendages, of enterotoxigenic Escherichia coli, or ETEC, help cause traveler’s diarrhea by aiding in the bacterium’s invasion of the small intestine.

Study results indicate the protein histatin-5 could be manufactured as a dissolvable powder to provide relief, researchers said. Before the study, researchers didn’t know salivai could be critical in keeping traveler’s diarrhea at bay.

“We found that the protein histatin-5 present in human saliva stiffens the pili of ETEC, preventing the bacteria from effectively adhering to the small intestine,” author Dr. Esther Bullitt, associate professor of physiology and biophysics at BUSM said in a university release. “If they can’t attach, they simply can’t cause disease.”

The study consisted of researchers exposing miniature human small intestines to ETEC with and without the presence of histatin-5. With histatin-5 in the picture, the small intestines faced significantly fewer bacteria.

Researchers said other salivary proteins might also protect against other diseases, including infectious gastritis, food poisoning or pneumonia.

“We believe that our data represent the first example of a new paradigm in innate immunity: the contributions of salivary components to preventing infection,” Bullitt said. “This research opens an untapped avenue for prevention of enteric infectious diseases through the targeted use of naturally occurring components of saliva.”

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