Animals and coronaviruses

Where do coronaviruses come from?

Coronaviruses (there are 4 groups) are quite common with animals, notably with farm animals, dogs, birds, marine mammals, rodents, etc. A large proportion of these animals are said to be asymptomatic carriers. This means that they’re able to transmit the virus to their congeners without being sick themselves. Only a small portion of all known coronaviruses can be transmitted from animals to humans. In the case of SARS-CoV-2, the pathogen responsible for Covid-19, the viral "reservoir" is believed to be derived from Asian wild species, possibly bats. On the other hand, the bats would not be responsible for the pandemic. Indeed, it takes an intermediary to transmit the virus to humans, possibly the pangolin or the civet which were offered at the public markets of Wuhan.

How can an animal virus infect a human being?

A vast majority of viruses are specific to a species or a distinct group of species. If a virus makes a cat ill and not its owner, this means that the virus is not equipped to attach itself to human cells: this is what we refer to as the species barrier. However, over time and with repeated contacts, viruses mutate and evolve, and some can acquire certain powers, among these, the ability to infect other species.

A disease that can be transmitted from animals to humans is called a zoonosis. The swine flu, Lyme disease, rabies, salmonellosis and the West Nile virus are but some examples of these. The virus is passed along through a bite, a scratch, a sting from an infected animal or by ingestion. Over the past 10 years, 75% of new diseases that have affected humans were caused by animal-originating pathogens. And, as we can observe, the current Covid-19 pandemic demonstrates this with daunting efficiency, and globalization only intensifies the level and amplitude of consequences.

What is the link between viruses and wildlife species trade?

Although the precise origin of the pandemic is still subject to debate, a majority of researchers are pointing fingers at the fact that humans are coming in too close proximity to wildlife. The world’s growing population, urban sprawl and economic development have contributed to expanding the limits of our cities, farmlands and pastures, therefore, relentlessly encroaching on what little space is left for wildlife. Deforestation and the development of roadways have allowed us to reach regions and resources that were inaccessible up until now. Dietary traditions and beliefs prompt certain communities to consume, in part or sometimes entire wildlife species for which preparation and conserving measures are often inadequate. The combination of all these factors has brought humans much more frequently in close proximity to wildlife. This is how we’ve increased the risks of being exposed to “new” viruses. The Global Virome Project’s goal is to improve our way of doing things during a pandemic. According to their research, there are more than 1.7 million viruses that have yet to be discovered in the world’s wildlife; nearly half of these could be detrimental for humans.

Should we be afraid that this type of viral outbreak could occur in a zoological garden?

The situations encountered inside wildlife markets in Asia and what we can experience visiting accredited zoos, such as the Zoo de Granby are incomparable. Animals here enjoy large spaces, isolated from visitors, and strict maintenance and hygiene guidelines are implemented. Zoo residents are constantly monitored by a veterinary team and are never part of any human food chain…

Some isolated human-to-animal transmission contamination cases have been reported: two dogs and two cats (Hong Kong and Belgium), as well as a tiger at the Bronx Zoo (New York); In the case of the tiger, it’s believed that the contamination was caused by repeated contact with an infected technician during a biomedical training session. Taking into account these rare cases, measures were taken by the majority of accredited zoological institutions. The Zoo de Granby has implemented protective and distancing guidelines for technicians responsible for residents that are considered more at risk to become potentially contaminated, for instance our tigers and primates.

How can I avoid contracting a zoonosis?

Although the chances are slim for you to be in close contact with a wild animal, you should know that your pets could be zoonosis vectors.

There are several simple measures you can take during the process of performing daily actions to prevent these diseases:

  • Wash your hands with warm water and soap after each time you come into contact with an animal, their feces, or litter box before eating or touching your mouth;
  • Adopt a strict personal hygiene when preparing or eating food;
  • Quickly and properly eliminate your animals’ feces;
  • Properly clean any scratch or bite with warm water and soap, then protect the wound with a bandage;
  • Avoid kissing animals;
  • Protect yourself against mosquito and tick bites.

Furthermore, when travelling, avoid buying or consuming products sourced from wildlife species. In addition to contributing to the protection of endangered species, you’ll minimize the risks of exposing yourself to foreign pathogens.