AS coronaviruses are notoriously promiscuous, we may see some animals being detected with the Covid-19 virus, as what has been reported in dogs, cats and tigers.
This does not always mean infected animals are transmitting the virus to humans or other animals. There is no cause for alarm, since all these animals are mildly ill, and they recovered after a few days. The animals harbour Covid-19 in small amounts, which are not enough to spread to humans.
In addition, the detection of the Covid-19 virus in pet animals is an isolated case, which can be prevented if pet owners practise good personal hygiene before and after taking care of their animals.
If the owners are not well, they should get someone else to take care of their animals, and stay away from their animals. And whenever possible, keep their animals indoors. There is no need for pet owners to screen their animals for Covid-19.
The authorities — the Veterinary Services Department, the Wildlife and National Parks Department and Universiti Putra Malaysia’s Veterinary Medicine Faculty — are working together to gather information, as well as with other agencies to monitor the situation.
The findings of a recent study on the experimental infection of Covid-19 in different animal species require careful interpretation.
The study indicated that ferrets and cats are susceptible to the virus infection in a controlled experiment; the virus infects poorly in dogs; while other animals, such as pigs, chickens and ducks, are not susceptible to the infection.
Even though cats are susceptible to the infection, the animals were infected with a high dose of the virus, and even then, they were having only localised infection in the upper respiratory tract.
Not all the infected cats were shedding the virus too.
This controlled experimental condition is unlikely to occur in the natural environment, so the chances of cats getting infected with Covid-19 naturally are very remote.
In addition, based on the surveillance of dogs and cats in badly-hit areas in China, especially in Hubei province, there were no unusual cases of sick dogs or cats.
Some of the animals even developed an antibody response against Covid-19.
Therefore, pets are unlikely to play a major role in transmitting the virus to humans.
Having said that, the hunt for a potential animal host of Covid-19 is important to determine the origin and further control the virus.
What we know is Covid-19 is caused by a SARS-like coronavirus, known as SARS-CoV-2, that shares 91 per cent similarity to SARS-like viruses from bats and pangolins.
Since coronaviruses have a diverse host range affecting birds and mammals, including bats, studies have shown that there is a small, but real possibility that the virus could jump into a new animal host and reintroduce it to humans.
A lesson learned from Covid-19 and other zoonotic coronaviruses — such as SARS-CoV and MERS-CoV, and also from diseases where bats are also the reservoir, such as Nipah, Hendra, Ebola, and Marburg — is to conduct surveillance in hotspot areas with high interactions between animals of different species and humans.
Hence, wet markets that sell live animals and any unchecked ecological and epidemiological changes that cause constant interactions between animals and humans may lead to the emergence of the novel virus, since this condition facilitates the virus jumping from animals to humans.
Surveillance, combined with scientific studies to better understand zoonotic animal coronaviruses and spillover, will enable us to stay a step ahead of the next epidemic.
The writer is Immunology and Infectious Diseases professor and Universiti Putra Malaysia’s Veterinary Medicine Faculty dean