An Overview of SARS-CoV-2 and Animal Infection

Abstract

A novel coronavirus has been reported as the causative pathogen of the Coronavirus disease 2019 (COVID-19) outbreak in Wuhan city, China in December 2019. Due to the rapid spread of the virus worldwide, it has been announced as a pandemic by the World Health Organization (WHO). Hospitalized patients in Wuhan were associated with the Huanan seafood wholesale market where live animals, such as poultry, bats, snakes, frogs, rabbits, marmots, and hedgehogs are sold in that market which suggests a possible zoonotic infection. It was suggested that bat is the natural host of SARS-CoV-2, but the intermediate host is still unclear. It is essential to identify the potential intermediate host to interrupt the transmission chain of the virus. Pangolin is a highly suspected candidate as an intermediate host for SARS-CoV-2. Recently, SARS-CoV-2 infection has been reported in cats, dogs, tigers, and lions. More recently SARS-CoV-2 infection affected minks severely and zoonotic transfer with a variant SARS-CoV-2 strain evidenced in Denmark, Netherlands, USA, and Spain suggesting animal-to-human and animal-to-animal transmission within mink farms. Furthermore, experimental studies documented the susceptibility of different animal species to SARS-CoV-2, such as mice, golden hamsters, cats, ferrets, non-human primates, and treeshrews. It is also essential to know the possibility of infection for other animal species. This short review aims to provide an overview on the relation between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and animals.

COVID-19 in animals: contact with humans and potential transmissions

“…After the initial SARS-CoV-2 diagnosis other mink farms in The Netherlands and other countries tested positive. Comparison of the viral sequences from mink and farm employees showed that human sequences were almost identical to the mink sequences from the same farms 1,7 . These data suggest that the source of the SARS-CoV-2 was human to mink transmission, followed by evolution while circulating in the mink population before transmission back to humans.…”

“…CoV-2 in dogs but experimental infections showed that dogs have a low susceptibility to SARS-CoV-2 and do not play a significant role in the epidemiology or transmission to humans [7][8][9]15 . The literature on SARS-CoV-2 in pigs is contradictory, with one study reporting no evidence of infection after intranasal challenge and a second study reporting low-level responses after experimental infection 16,17 .…”

“…The horseshoe bat is the reservoir host of SARS and MERS and bats are most likely the reservoir host of SARS-CoV-2. SARS and MERS are both transmitted from bats to humans through intermediate hosts, palm civets and camels respectively, and it is likely that SARS-CoV-2 is transmitted through an as yet unidentified intermediate host 1,5,7 . No clinical signs were observed in any experimentally infected bats but virus was isolated from nasal and tracheal samples, which is characteristic of a reservoir host 5 .…”

“…Four Malayan tigers and three African lions in the Bronx Zoo showing respiratory signs tested positive, with the virus found in respiratory tract samples. The virus was probably transmitted from an asymptomatic keeper as the genome of a tiger isolate had a high homology to human strains of the time 1,7,8 .…”

“…Mice showed varying results depending on the breed of mice and the virus used [4][5][6]19 . Several species of hamster have demonstrated clinical disease 5,7 . Other species have been implicated in the epidemiology of SARS-CoV-2, but space restrictions do not allow these to be discussed.…”