A year ago, humanity embarked on a project to immunize everyone against Covid-19. A shadow vaccination campaign has been taking place. Zoos around the world have been inoculating their animals with an experimental Covid vaccine as an insurance policy against what they fear could be a similar fatal illness for certain mammals.
The scale of Covid-19 infections in our furry household companions and what the consequences could be for their health are some of the questions veterinary scientists are trying to understand.
Two hippos at the Antwerp zoo in Belgium contracted Covid from humans last week. Imani and Hermien had no symptoms apart from their noses, but other animals haven't been so lucky. Three snow leopards died from Covid-related problems at a children's zoo. Zoos have reported infections in animals.
Most of the scientific focus has been on human cases of disease, even though it is thought to have originated in an animal. Scientists have been concerned about the possibility of other animal infections since the early days of the Pandemic.
coronaviruses have a tremendous capacity to jump species. Margaret Hosie, a professor of comparative virology at the University of Glasgow, said that it was always predicted that there would be a variety of domestic animals.
If other animals can transmit the virus, this could put pressure on the virus to adapt and acquire new genes, raising the possibility of new strains that could be transmitted back to people. Hosie said that the virus could be mutating quietly in an animal species, and getting hotter and hotter.
A dog in Hong Kong tested positive for an animal disease in February 2020 and is thought to have contracted it from its owner. There have been many reports of dogs and cats with Covid. ferrets and golden hamsters can catch Covid-19, but dwarf Roborovski hamsters can die from it.
Research shows that cat and dog infections are common. In 20% of households where pet owners had tested positive for Covid, the cats and dogs had an immunity to the virus.
Most of the time, an animal with an infectious disease will make an uneventful recovery. Some may experience more severe illness.
The first cat that we identified as being infectious from its owner was a young kitten that died of pneumonia. The pathology was very similar to the viral pneumonia seen in Covid-19 patients, so we couldn't say for sure, but we did test exhaustedly for other potential pathogens.
Are these pets infectious? The risk of onward transmission is low because it is difficult to isolated from dogs.
The jury is still out on cats. Experimental studies suggest that they can cause harm to other cats, but the degree to which this happens in the real world is not certain. Cats don't spend a lot of time with other cats or humans. If they catch Covid-19, their owner is likely to be the source, and any onward transmission is likely to be very limited.
Farmed mink are very susceptible to infections with the disease, and are forced to live in close proximity to one another. They can die from pneumonia.
The news that the virus had crossed from humans into animals sounded alarm bells around the world. Hosie said that the wake-up call was a reason for more emphasis on studying viruses at the human animal interface.
The European Food Safety Authority and the European reported that the mink-related variant viruses have not shown to be more transmissible or causing more severe impact compared to other circulating sars-coV-2
Millions of mink were culled as a result of being exposed to the disease. Farm workers can be equipped with protective equipment.
Another option is a vaccine. Russia's state veterinary service approved a vaccine for use on fur farms in March, after clinical trials on cats and dogs.
The US Department of Agriculture has given the go-ahead for the experimental use of a vaccine developed by the American animal health company. The San Diego zoo was given enough doses of inoculate its great apes after the western lowland gorilla troop became ill with Covid.
The senior vice-president of biologics research and development at the company said that they have had multiple requests from different zoos. I think 100 species of mammals have been vaccined.
Significant transmission among wild animals would be more concerning than a farm outbreak. If a vaccine worked in that species, it would be impractical to vaccine them.
White-tailed deer, which are native to North, Central and South America, can transmit the virus to each other. In August, researchers at the US National Wildlife Center in Fort Collins reported that up to a third of white-tailed deer in the US north-eastern region had an immunity to sars-coV-2. They are not sure how they became infections.
If white-tailed deer transmit the virus to each other in a significant way, that could be problematic, although if a potentially dangerous new variant arose in them, it would still need to be transmitted back to us.
Rebecca Fisher is an assistant professor of epidemiology at Texas A&M University.
Her greatest fear is the virus adapting to wild animals that live in close proximity to humans. Rats and mice don't seem to be at risk of being bitten by the disease at the moment.
It could pay to be alert because of the risks. Alan Radford, a professor in veterinary health informatics at the University ofLiverpool, said that the current Pandemic is maintained by human transmission.
The most likely source of new variant is the continued circulation of the virus in humans. We still present a higher risk to our pets than they do to us.
This is unfortunate. Fisher said that snuggling with our pets is better when we are sick or convalescing. If we are sick, we must not interact with them and not give them anything. We need to protect them the same way we would our children.
