Insights into cross-species infection: Porcine epidemic diarrhea virus infections in the rodent

The cross-species infection of coronaviruses has resulted in several major epidemics since 2003. Porcine epidemic diarrhea virus (PEDV) is a devastating swine enteric coronavirus, which targets pigs as the only natural reservoir. In this study, the nucleic acid of PEDV was detected in rat fecal samples collected from pig farms. Further animal tests showed that PEDV can cause systemic infections in neonatal mice and rats via intracranial inoculation. The brain, lung, intestine and spleen were all targets for PEDV in rodents in contrast to the intestine being targeted in pigs. Morbidity and mortality vary via different infection routes. PEDV was also detectable in feces after infection, suggesting that the infected rodents were potential infectious sources. Moreover, the cerebral tropism of PEDV was verified in piglets via orally inoculation, which had not been identified before. In conclusion, our findings demonstrate that PEDV could cross the species barrier to infect mice and rats through different routes in experimental settings. Although it is highly devastating to piglets, PEDV changes the target organs and turns to be milder when meeting with new hosts. Based on these findings, more attention should be paid to the potential cross-species infection of PEDV.