SARS-CoV2
Updated 04/08/2020
Which species are susceptible to SARS-CoV2?
The domestic and wild species most sensitive to SARS-CoV2 are the cat and other felines as well as the ferret. The dog is a susceptible species but infection seems less easy probably due to a different structure of the cellular receptor for the virus compared to other species. Poultry and pigs are not susceptible to the virus.
The cat had already been identified as a species susceptible to infection by SARS-CoV which appeared in 2002.
The intermediate hosts of SARS CoV2 would be the bat and/or the pangolin.
Cases have been confirmed in cats and/or dogs in Hong Kong, Europe (Belgium, Spain, Germany, France, Russia, United Kingdom) and the United States.
How do animals become contaminated in natural conditions?
Pets : during close contact with infected people. Cases have been described in animals sleeping in the bed of the infected person and/or licking plates after a meal…
However, other animals, dogs or cats living in contact with infected or sick veterinary students were not infected.
Although cat-to-cat contamination is possible, no cases of natural transmission have been documented to date. On the other hand, in some homes several cats were seropositive.
Farmed and captive animals : the contamination seems in this case to be rather indirect via the contaminated environment and/or food (e.g. wild felids contaminated in a zoo in New York or even farmed mink in the Netherlands).
What is the prevalence of infection in animals?
The first retrospective epidemiological studies show an extremely low prevalence in animals presenting respiratory clinical signs (Idexx study, Scanelis study, University of Glasgow); however it seems likely, based on the results of experimental infection, that the infection is preferentially asymptomatic, particularly in cats. In the absence of systematic research in pets living in contact with infected people, the real prevalence, although presumed to be low, is therefore currently unknown.
A serological study carried out on cats in the province of Wuhan in China, very strongly affected by the pandemic and which underwent very strict confinement, showed a serological prevalence of 15% in cats.
What are the clinical signs described in infected animals?
The cases described report respiratory (in particular coughing, coughing and dyspnea) and/or digestive (diarrhea, vomiting) disorders in cats, dogs, mink and certain wild felines.
These clinical signs subside within a few days (no reported cases of mortality to date)
However, these descriptions are rare, and often in the absence of differential diagnosis and quantitative results concerning the viral load, it is difficult to know whether SARS-CoV2 is the cause or the only cause of the signs observed.
Experimental infections in very young cats (10-14 weeks) have led to the appearance of respiratory signs and lung lesions similar to those described in humans. Older cats subjected to the same infection conditions did not develop clinical signs.
Is contagion possible within the same species?
Just as for SARS CoV which appeared in 2002, this has been demonstrated in cats for SARS-CoV2. Uninfected cats brought into contact with experimentally infected cats shed the virus 2 to 3 days later and over a period of approximately one week.
And between species?
All identified cases of Covid-19 in domestic and wild animals are currently of human origin. On the other hand, cats became contaminated through contact with farmed mink in the Netherlands (these cats had access to the breeding premises). And more worryingly, mink is strongly suspected of being the cause of human contamination (several outbreaks in the Netherlands), which raises fears that mink could be a reservoir of viruses and has justified the systematic culling of minks in breeding in the Netherlands.
Are domestic carnivores a source of viruses for the environment?
As the virus is excreted in nasal secretions, in saliva and possibly in stools, contamination of the environment is possible but this has not been evaluated. Likewise, it is possible, particularly in the feline species, that the coat of infected animals is contaminated and that the virus can persist for a few hours. No specific study is available on this point but reinforced hygiene measures are recommended when handling your pet; Contact between infected people and their pets should also be avoided.
When to test an animal?
International recommendations in terms of screening suggest reserving virological analyzes (Rt-PCR) for animals living in contact with sick people or people who test positive or who present compatible clinical signs. Following the discovery of cases in a residence for the elderly in Germany which involved 3 cats, it is also recommended to test animals living in contact with vulnerable people in specialized medical establishments.
In the event of clinical suspicion in animals, a differential diagnosis is strongly recommended because infectious agents that can potentially give compatible clinical signs are very common in the feline species.
Due to the priority needs in humans, the use of diagnostic kits for human use for routine screening in animals is not recommended.
The use of tests for veterinary use must therefore be favored.
Can we fear cross-reactions with RT-PCR tests in cats, dogs or ferrets carrying coronavirus?
Feline and canine coronaviruses, as well as those described in ferrets, are genetically distant from SARS-CoV2. Tests that can be used in animals must have been validated on the absence of cross-reactions with the coronaviruses of the species in question, which is the case for the SARS - CoV 2 Scanelis test with respect to ferret and feline coronaviruses. and canines (including canine respiratory coronavirus).
The test can therefore be carried out safely in these 3 species.
