Corona virus in animals Print E-mail
News - Rubrieke
Wednesday, 25 March 2020 06:52
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Dr Liesel van der Merwe is a small animal medicine specialist. Send her your questions: This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Dr Liesel van der Merwe

Let’s talk about corona virus in our companion and domesticated animals: Members of the corona viruses are among the most numerous viruses infecting a wide variety of animals, including birds and humans.

The virus group is responsible for respiratory and gastrointestinal disorders. The genomes (genetic make-up) of all corona viruses have similar structures and organisation, but they also have unique group or even strain-specific genes.

Corona viruses (CoVs) are characterised by high genetic diversity, which is the result of much virus mutation and recombination, which can lead to the emergence of new viruses. These viruses can have new characteristics that even enable them to switch to new hosts.

Most corona viruses cause clinical disease in the species from which they were isolated but natural and experimental transmission to other species is possible. These newly created viruses can also acquire zoonotic potential, as seen with the severe acute respiratory syndrome (SARS), the epidemic from Southern China in 2003 and the current COVID-19 outbreak.

Corona virus infection is a very common infection in animals with almost all species having some species-specific corona virus causing disease. In cats feline corona virus is an enteric form, meaning it causes gastrointestinal disease. Most infections do not show any symptoms, but in some animals mild diarrhoea develops.

In cat households with more than six to eight cats, the disease becomes ubiquitous. After infection most cats shed the virus for a few weeks. Infection is by the faeco-oral route. And yes, cats are very fussy about what they eat, but they groom themselves and the virus particles will be in the fine dust from the litter tray.

In multi-cat households there is constant re-infection by shedders. Some cats also become persistent shedders in that they are asymptomatic, but still harbour the virus in the colon. These cats can shed large amounts of virus in the faeces.

The fact that cats are infected with feline enteric corona virus puts them at risk of developing feline infectious peritonitis (FIP), a fatal disease in cats. It is not understood how, but changes in the normal enteric corona virus cause a mutation to the virus, which allows it to enter the cat’s blood stream.

Once in the body, development of FIP depends on whether the immune system can eradicate the infection or whether the immune system just develops antibodies to the virus. This antibody virus complex causes severe vasculitis: Inflammation and leakage of serum from the small capillary blood vessels.

Dogs are infected with at least three types of corona virus. The most common one is also the intestinal (enteric) corona virus and is prevalent in many canine and related species, especially in group housing facilities.

The spread of the virus is by the faeco-oral route. Affected dogs will only shed for six to nine days, a much shorter time than infected cats. Infected dogs will generally develop diarrhoea. In the majority of cases the disease is mild, but can require medical supportive treatment and hospitalisation in very young puppies.

Canine respiratory corona virus is a relatively newly discovered infection (2003, England) and is genetically related to the human and bovine corona viruses which cause respiratory disease.

It is in a different group from the enteric corona virus. The virus is common in the UK, Greece, USA, Italy and Japan. The disease is highly contagious and is spread by direct dog-to-dog contact, aerosols of respiratory secretions generated by coughing and sneezing, and contact with contaminated environments, such as food and water bowls, collars and leashes and the hands and clothing of people who handle the infected dog.

The incubation period is four days and shedding is likely for seven to ten days. The virus is easily inactivated by quaternary ammonium disinfectants commonly used in veterinary clinics.

Disease is evidenced by rapid onset of sneezing, coughing and a nasal discharge for a short period. The disease is part of the “kennel cough” group of infections and is generally self-limiting. Secondary bacterial infections can worsen the signs and co-infection with other viruses is likely responsible if a pneumonia develops.

Bovine corona virus infections are associated with three diseases in cattle: Calf diarrhoea, winter dysentery (haemorrhagic diarrhoea) in adult cattle and respiratory infections in cattle of various ages, especially in feedlot cattle. The bovine corona viruses can infect other animal species, including wildlife. Bovine corona virus is closely related to the human corona virus OC43 that causes the common cold.

Corona virus in pigs also has a respiratory and enteric form caused by related but different corona viruses.

So, corona viruses have been around for a very long time; one article I read cites 300 million years. The virus, by its very genetic makeup, is prone to rapidly adjust and mutate. In my opinion humans would be very lucky to not be infected episodically, as this virus mutates and changes hosts.

“The thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under the sun.”(Ecclesiastes 1:9)

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