Infectious stability of animal gastrointestinal coronaviruses in fasted-state simulated gastric fluid.

Animal gastrointestinal coronaviruses such as porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis virus (TGEV) can cause oral infection despite being enveloped viruses, implying that they are capable of passing through the highly acidic gastric lumen. This study focused on the low pH acid resistance of coronaviruses, including PEDV, TGEV and equine coronavirus (ECoV) in fasted-state simulated gastric fluid (FaSSGF) at pH 1.6, which simulated gastric fluid. Interestingly, PEDV, TGEV and ECoV retained infectivity in FaSSGF, whereas SARS-CoV-2 was rapidly inactivated. Although FaSSGF containing surfactants did not affect the acid resistance of these gastrointestinal coronaviruses, FaSSGF including pepsin showed inactivation effects against PEDV, TGEV and ECoV. These findings suggest that animal gastrointestinal coronaviruses possess the potential ability to withstand low pH conditions in gastric acid environments.