There have been several theories indicating the spread of COVID-19 from organisms like bats, chickens, pigs, and ferrets. This study aims to investigate the susceptibility of potential animal hosts and the risk of anthroponotic spill-over infections.

The researchers inoculated nine fruit bats, nine pigs, nine ferrets, and 17 chickens. Three direct contact animals were included 24 hours after inoculation to test viral transmission. The team monitored the animals for clinical signs and virus shedding from nasal washes & rectal swabs (ferrets, pigs), oral swabs & pooled feces samples (fruit bats), and oropharyngeal & cloacal swabs (chickens) after 2,4, 8, 12, 16, and 21 days after the infection.

It was found that chickens and pigs were not susceptible to SARS-CoV-2. All organ samples, swabs, and contact animals were found negative for viral RNA, and none of the chickens or pigs was seroconverted. Seven out of nine (78%) fruit bats had a transient infection with a detectable virus. The viral RNA was also present in the trachea, lungs, and lung-associated lymphatic tissue. Efficient virus replication with no clinical signs was observed in ferrets.

The research concluded that pigs and chicken could not be intranasally infected by SARS-CoV-2, whereas fruit bats showed characteristics of a reservoir host. In ferrets, virus replication was noticed that resembled human infection with an efficient spread.