“Stomach Viruses” replicate in Salivary Glands and Transmit through Saliva Dr. Sourish Ghosh, Senior Scientist, CSIR-Indian Institute of Chemical Biology, Kolkata Acute Gastroenteritis (AGE) accounts for ~685 million cases/year worldwide out of which 1 in 5 cases are due to norovirus infection (CDC, March 2021). Community transmission due to these enteric viruses have been so far considered to be through fecal-oral route and intestinal cells as primary site of replication. My research (Ghosh S et al., Nature, 2022) revealed for the first time that enteric virusesnorovirus, rotavirus, astrovirus replicate in salivary glands in addition to intestinal cells. Apart from fecal-oral route of transmission enteric viruses also spread through saliva in the community. In addition, I observed that infected pups can transmit the virus to mothers’ mammary glands while suckling. This transfer of virus during suckling stimulated secretion of IgA into milk which further helped in clearance of the virus from pups’ intestine. My experiments further showed salivary glands are sites of persistent replication for these enteric viruses and act as reservoirs in immunocompromised mice that favors evolution for new strains. Human norovirus lacks an effective vaccine and there are major gaps in our knowledge of the respective viral entry receptors and host replication co-factors due to lack of robust cell culture models. My discovery of salivary gland replication of murine strains of noroviruses led me to identify salivary epithelial cell lines that could sustain human norovirus replication. This research reveals: (1) a new organ to explore studying host-pathogen interactions for enteric as well as other viruses infecting mucosal tissues. (2) Salivary gland replication of enteric viruses is significant not only due to epidemiological reasons but also as a novel saliva based rapid diagnostic assay. (3) Our research also has implications for development of new mammary gland-based vaccination strategy for protecting newborns.