National Institutes of Health scientists have found that a class of viruses that cause severe diarrheal disease can form in the salivary glands of mice and spread through saliva. The findings indicate that there is a new route of transmission for these viruses, which infect billions of people worldwide every year and can be fatal.
Microscopic examination of a mouse shows salivary gland acinar epithelial cells (pink) infected with rotavirus (green), a type of viral intestinal infection.
Transmission of enteric viruses through saliva potentially suggests that coughing, sneezing, sharing food and utensils, and kissing can spread the virus. The findings still need to be confirmed in human studies, but they could lead to better ways to prevent, diagnose, and treat diseases caused by these viruses.
Intestinal viruses such as noroviruses and rotaviruses are known to be spread by eating food or drinking liquids contaminated with faeces that contain these viruses. Previously, these viruses were thought to bypass the salivary gland and target the intestines directly, and then simply exit through the feces.
Researchers will now need to confirm that transmission of enteric viruses through saliva is possible in humans. This potential finding may explain why a large number of enteric viral infections find it difficult to consider fecal transmission as the only route of transmission.