SARS-CoV2

Which species can be infected with SARS CoV2?

The domestic and wild species most susceptible to infection to SARS-CoV2 are cats and other felids, as well as ferrets. The dog is a susceptible species but the infection seems less likely unlike other species due to a potentially different structure of the cellular receptor to the virus. Poultry and swine are not sensitive to the virus.
The cat has already been identified as a species sensitive to infection to the SARS-CoV first isolated in 2002.
Intermediate hosts of SARS-CoV2 would be the bat and the pangolin. Cases of cat and/or dog infections have been confirmed in Hong-Kong, Europe (Belgium, Spain, France, Russia, Germany and the UK) and the US.

How do animals get infected in natural conditions?

Domestic animals : having close contact with infected people. Cases were described where animals would sleep in the bed of an infected and/or lick the plates after meal…
Nevertheless, other animals, dogs or cats living in contact with veterinary students infected or ill with the virus have not been infected.
Even though contamination from cat to cat could be possible, no case of natural transmission has been documented to this day. However, in some households, several cats were seropositive.
Farmed animals and animals in captivity : Contamination in that case seems to be indirect through environment and/or contaminated food ((i.e wild felines in a New-York zoo or farmed minks in the Netherlands).

What is the prevalence of infection in animals?

The first retrospective epidemiological studies report an extremely low prevalence in animals showing respiratory clinical signs (Idexx study, Scanelis study): however, it seems likely according to results of experimental infection that the infection is preferentially asymptomatic, particularly in cat.
In the absence of systematic research in pets living with infected people, the real prevalence, however low it is presumed to be, is unknown to this day.
A serological study realized on cats in the Wuhan province of China, which was strongly affected by the pandemic and was subjected to a very strict containment shows a prevalence of 15% in cats.

What are the described clinical signs in infected animals?

The described cases indicate respiratory troubles (more particularly coughing, nasal discharge and dyspnea) and/or digestive troubles (diarrhea, vomiting) in cats, dogs, minks and some wild felines. These clinical signs disappear within a few days (no reported mortality case to this day).
Nevertheless, these descriptions are sparse, and often, in the absence of a differential diagnosis and quantitative results of the viral load, it is difficult to say whether SARS-CoV2 is the cause or the only cause of the observed signs.
Experimental infections of young kittens (10-14 weeks old) led to the appearance of respiratory troubles and pulmonary lesions similar to the ones described in humans. Older cats subjected to the same infection conditions did not develop signs.

Is contagion possible within the same species?

Like SARS CoV in 2002, it has been proved to be the same with the SARS-CoV2 for the cat. Uninfected cats put in contact with experimentally infected cats shed the virus 2 to 3 days later for about one week.

And between species?

All the identified cases of Covid-19 in domestic and wild animals come from humans. However, some cats got contaminated by contact with farmed minks in the Netherlands (said cats had access to the farming locations). Even more worrying, the mink is suspected to be the source of human contamination (several outbreaks in the Netherlands), which raises concerns about the mink being a virus reservoir and would justify the slaughter of breeding minks.

Are domestic carnivores a source of virus for their environment?

The virus being shed in nasal secretions, in saliva, and sometimes in stools, the environmental contamination is possible but has not been evaluated. Likewise, it is possible, especially in the feline species, that the fur of infected animals could be contaminated and for the virus to persist for several hours. No specific study has been available so far but reinforced hygienic measures are strongly advised when handling your pet; contacts between infected people and their pets are to be avoided.

When to test an animal?

International recommendations regarding testing suggest to reserve virologic analyses (Rt-PCR) for animals living in contact with ill or positive-tested or people with compatible clinical signs. Following the case of 3 cats in a seniors’ residence in Germany, it is recommended to screen animals living in contact with fragile people in specialized medical facilities as well. In case of clinical suspicion in an animal, a differential diagnosis is strongly recommended as infectious agents able to showcase compatible clinical signs are frequent in the feline species. Due to the priority needs of humans, the use of diagnosis kits for systematic screening in humans is not recommended. The use of screening for veterinary purposes must be privileged.

Should we fear cross reactions with RT-PCR screening of coronavirus-positive cats, dogs or ferrets?

The feline and canine coronaviruses, as well as those described in ferrets are genetically distant from SARS-CoV2. The screening in use for animals have to be validated on the basis of having no cross-reactions with the coronaviruses of said species, which is the case for the SARS-CoV2 Scanelis screening in regards to the ferret, cat and dog coronaviruses (including the canine respiratory coronavirus). As such, the screening can be safely carried out for the 3 species.