Transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to animals: an updated review

Abstract

COVID-19 caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) originated in Wuhan (Hubei province, China) during late 2019. It has spread across the globe affecting nearly 21 million people with a toll of 0.75 million deaths and restricting the movement of most of the world population during the past 6 months. COVID-19 became the leading health, economic, and humanitarian challenge of the twenty-first century. In addition to the considerable COVID-19 cases, hospitalizations, and deaths in humans, several cases of SARS-CoV-2 infections in animal hosts (dog, cat, tiger, lion, and mink) have been reported. Thus, the concern of pet owners is increasing. Moreover, the dynamics of the disease requires further explanation, mainly concerning the transmission of the virus from humans to animals and vice versa. Therefore, this study aimed to gather information about the reported cases of COVID-19 transmission in animals through a literary review of works published in scientific journals and perform genomic and phylogenetic analyses of SARS-CoV-2 isolated from animal hosts. Although many instances of transmission of the SARS-CoV-2 have been reported, caution and further studies are necessary to avoid the occurrence of maltreatment in animals, and to achieve a better understanding of the dynamics of the disease in the environment, humans, and animals. Future research in the animal–human interface can help formulate and implement preventive measures to combat the further transmission of COVID-19.

An Overview of SARS-CoV-2 and Animal Infection

“…Pangolin is a highly suspected candidate as an intermediate host for SARS-CoV-2 (20). Recently, SARS-CoV-2 infection has been reported in cats, dogs, minks, tigers, and lions (28,31,(35)(36)(37). Furthermore, experimental studies documented the susceptibility of different animal species to SARS-CoV-2, such as mice, hamsters, cats, ferrets, non-human primates, and treeshrews (6,24,30,38,39).…”

“…Until now, several cases of human-to-animal transmission during the pandemic have been reported in several countries worldwide, including Hong Kong, Belgium, Germany, United States, Spain, Netherlands, Denmark, and France (23,31,57). Although there is no evidence that animals had a role in the spread of the SARS-CoV-2 pandemic (58), there is a raising alarm that animals may get infected and transmit the virus to humans (37). (32).…”

“…This tiger was the first infected tiger anywhere in the world and the first case of human to non-domestic animal transmission (36,60). Later, the infection has been detected in four tigers and three lions (37,70) indicating that different feline species are susceptible to SARS-CoV-2 infection (60). It was suspected that the tiger received infection from an infected asymptomatic employee (13,36,70).…”

Susceptibility of livestock and companion animals to COVID‐19

“…So far, the COVID‐19 natural incidences that occurred in cats, dogs, minks, and captive wild animals have a common factor, which is the proximity to humans. The sequence identity of tiger SARS‐CoV‐2/USA/NY‐040420 EPI_ISL_420293, mink SARS‐CoV‐2/NB04 EPI_ISL_447634, cat SARS‐CoV‐2 EPI_ISL_437349, and dog SARS‐CoV‐2/HKG/20‐03695/2020 with human SARS‐CoV‐2 are 99.96, 99.9, 99.85, and 99.51% respectively 31 . Outside China, not a single case was reported on the animal–animal transmission or animal–human transmission.…”

Therapeutic MK-4482/EIDD-2801 Blocks SARS-CoV-2 Transmission in Ferrets

“…However, human SARS-CoV-2 cannot productively infect mice without extensive viral adaptation or introduction of human ACE2 into transgenic animals, and none of the mouse models supports transmission to uninfected mice 10 . Spillover of SARS-CoV-2 to farmed minks, subsequent large-scale mink-to-mink transmission and, in some cases, zoonotic transmission back to humans revealed efficient viral spread among members of the weasel genus without prior adaptation [11][12][13][14] . Although mink farms reported elevated animal mortality and gastrointestinal and respiratory clinical signs 15 , outbreak followup revealed continued intra-colony spread for extended periods of time 14 , suggesting that acute clinical signs in the majority of infected animals may be mild or absent.…”