Article: WSAVA puts focus on epidemiological data gathering to fully understand COVID-19 pet risk

This article is taken from our Animal Pharm platform dated 22/04/20.

The World Small Animal Veterinary Association (WSAVA) has confirmed there is no evidence pets are a transmission risk during the ongoing COVID-19 pandemic and highlighted the importance of ongoing data gathering.

A WSAVA webinar in partnership with Zoetis and the Purina Institute outlined the current events surrounding the outbreak, information that has come to light regarding virus interaction with animals and how vets should approach the crisis.

The organization said the amount of information concerning infection of dogs and cats with SARS-CoV-2 is minimal at this point in time, although the situation is rapidly evolving. It encouraged people to frequently monitor official industry body websites for new information in the coming days and weeks.

Dr Lizzie Parker, global head of the Purina Institute, explained owners are increasingly turning to their vets for facts and reassurance their pets will be OK during the pandemic. She said, aside from SARS-CoV-2 being a new virus and industry having to keep up with the evolving situation, a big challenge is tackling the misrepresentation of information by the media.

She commented: "This is causing a lot of concern and distress among pet owners, but it also poses a very real and significant threat to pet welfare."

Michael Lappin, chair of the WSAVA One Health Committee, is currently working on a 'reverse zoonoses' statement for scientific publication, to provide comment on the issues surrounding pets during the crisis - particularly cats, after indications the species is susceptible to SARS-CoV-2. He stressed he will be making the conclusion there is still no evidence of cats-to-people transmission.

At the WSAVA-level, Dr Lappin revealed the organization's One Health Committee has also partnered with the Scientific Advisory Committee to set-up a resource site.

World caught off-guard by new virus

Dr Lappin explained coronaviruses are not necessarily a new threat. Other coronaviruses are already a problem in pets, such as feline infectious peritonitis (part of the alpha group) and canine respiratory coronavirus (the one coronavirus in small animals belonging to the beta group).

He also highlighted historical cases of Middle East respiratory syndrome (MERS) identified in 2012 and SARS-CoV-1 in 2002/2003 in humans - both belonging to the beta group like the new SARS-CoV-2 strain.

Dr Lappin said: "We're used to these viruses but we weren't ready for SARS-CoV-2. Back in 2002/2003, that first infection in this class of betas that infects people and can cause fairly significant disease was our predecessor. Shortly after, we saw MERS and now the mutant SARS-CoV-2.

"To be clear with our definitions, the virus is SARS-CoV-2 that we're dealing with now - the disease syndrome in people is COVID-19. Sometimes the definitions are lost with people that aren't in the sciences and sometimes this leads to some confusion."

He noted other examples of confusion during reporting on the pandemic, such as that witnessed "with some of the early cruise ship data, where it was stated this virus was on railings on the ships for as long as 17 days". Dr Lappin suggested this statement made people think SARS-CoV-2 would actually 'live' for 17 days.

Turning to current testing methods for SARS-CoV-2 detection, he remarked: "That work was actually based on PCR testing, which is a fantastic tool to prove nucleic acids of viruses, bacteria, etc. In this case, we've been doing quantitative reverse transcription PCR (RT-PCR) but that doesn't actually prove the virus is live.

"What we have to do when we're using PCR is discriminate whether or not a virus is just from a contaminated environment. So, whether it's not actually a living virus, versus if the virus is still there and potentially active. That's where virus isolation and culture can really help us because that proves whether the virus collected from a surface, a nasal swab, a rectal swab, is still viable."

Dr Lappin stated serology can be beneficial in "sorting out what's going on epidemiologically, as well as what's happening with one animal". He pointed out the body is "probably not going to make antibodies unless that virus, bacteria, protozoan is truly infecting you".

"Right now with SARS-CoV-2, we believe virus isolation proves live virus in a particular sample," he continued. "The higher level PCRs are being persistently PCR-positive and while not always proving live virus, probably prove current infection. Then seropositivity - that might develop a little bit later - also probably suggests the body cared enough to react and an infection probably existed at some point."

Vanessa Barrs, professor of companion animal health at the City University of Hong Kong, said the SARS-CoV-1 epidemic in 2003 gives some insight into why Hong Kong has been proactive in testing companion animals in the current COVID-19 pandemic.

She commented: "During that SARS-CoV-1 outbreak in 2003, there was a large cluster of infections in a housing estate in Hong Kong. Most of those cases were from people living in one block of flats, above or below each other with no direct contact. So, there was an investigation to determine whether pests might be involved in direct spread - pests like rats and cockroaches. They were quickly ruled out.

"Later, it was actually aerosol spread from sewage drains that was identified as a cause of transmission. But before finding that out, investigators also collected samples from cats and dogs living in that same housing estate where there was that large cluster of infections.

"What they found for the first time is most cats and dogs tested positive on multiple swabs by PCR on consecutive days. They did culture virus from the cats and five of the cats were also seropositive, confirming that they were infected. But importantly, none of those animals were sick and there was no evidence during the SARS-CoV-1 outbreak of 2003 of any animal-to-human transmission.

"As a follow-up to the natural infection of cats and dogs in the SARS-CoV-1 outbreak, investigators then looked at experimental infection to look at whether cats and ferrets were susceptible, and they also performed transmission studies."

During this research, cats and ferrets were infected intratracheally by virus taken from a human patient. Investigators took daily swabs and performed transmission studies.

They found both species could be experimentally infected. None of the cats became ill but they all spread virus from their respiratory tract and virus was transmitted to other previously uninfected cats, which also did not become sick. Similar results were shown with ferrets, except some did become ill and one died.

Dr Lappin remarked: "Things [subsequently] kind of quietened down. We would by definition say that SARS-CoV-1 was a reverse zoonosis because cats did become infected from people. But, to restate, there was never evidence it then went from a naturally infected cat into a human."

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Posted 30 April 2020 by Sian Lazell, Analyst, IHS Markit