Dog testing positive for Coronavirus

In Hong Kong at the end of February a dog tested positive for coronavirus and was isolated until it tested negative although it showed no symptoms. This peaked my interested because I was unaware that the coronavirus could be transmitted to dogs. Indeed, upon further research it appears that dogs cannot be infected.

So why did this dog tested positive? Apparently this was because the dog was exposed to the coronavirus without contracting it itself. This means that the presence of the virus on the dog caused the positive result and that dogs (as of yet) cannot catch the coronavirus.


Animal origins of the Coronavirus

Something that I thought was very topical at the moment was the Coronavirus. According to the Centers for Disease Control and Prevention (CDC) coronaviruses are a large family of viruses — most infecting animals, such as camels, cats and bats. In rare cases, like the current outbreak, the virus can evolve to affect humans. In the past 17 years, severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) have affected humans. Both of these viruses were classified as zoonotic viral diseases. This means that the virus was transferred directly from animals to humans, for this to happen genetic mutations of the virus had to occur to allow it to infect humans. Studies have proven that the original source of SARS-CoV and MERS-CoV was from a bat. However, humans did not catch these viruses directly from bats, there were intermediate host which carried the disease such as masked palm civets and camels.

The origin of the current coronavirus is still unknown. Scientists in China have invested samples of the virus from nine affected patients to determine its genetic code, whilst the World Health Organisation have named this particular virus as 2019 novel coronavirus (2019-nCoV). The genetic sequence of this strand of the virus was compared to over 200 animal coronaviruses to try to spot similarities between genomes. Scientists believe that 2019-nCoV could be a recombination of two existing viruses – one thought to have affected bats and the other unknown.  Indeed, studies have found that 2019-nCoV is 96% identical at whole genome level to a SARS-like coronavirus found in bats.

Many other hosts of the coronavirus were investigated and the most similarities in protein codes were reportedly found in snakes. So could 2019-nCoV be a mixture between a bat and a snake coronavirus? It is still unknown.There is currently ambiguity as to whether snakes can be infected to the virus at all as there is a significant lack of evidence to support that coronaviruses can affect animals other than mammals and birds.