Scientists have found one new canine coronavirus in a handful of people who have pneumonia. This may sound alarming, but once we unpack it you will find that there is no reason to lose your sleep.
The discovery of canine coronavirus in eight people at a hospital in Sarawak, Malaysia was reported in Clinical Infectious Diseases by a group of highly respected international scientists. So does this mean that dogs can transmit coronavirus to humans?
The first thing to clarify is what canine coronavirus is. What is important is that it differs significantly from SARS-CoV-2, the virus that causes COVID-19. The coronavirus family can be divided into four groups of viruses: alpha, beta, gamma, and delta coronaviruses. SARS-CoV-2 falls into the group of beta coronaviruses, while the canine coronaviruses fall into the completely separate group of alpha coronaviruses.
Scientists have known about coronaviruses for dogs almost 50 years. These viruses were relatively obscure for most of this period and of only interest to veterinary virologists and the occasional dog owner. There are no previous reports of these viruses infecting humans. But the sudden international spotlight on all coronavirus is finding coronavirus in places we haven’t seen before.
The canine coronavirus infections recently identified in humans were actually discovered by accident. Scientists weren’t specifically looking for canine coronavirus, and affected patients had long since recovered. The researchers tried to develop a new test that could detect all types of coronavirus at the same time – something called a test Pan-CoV test.
After confirming the test, they worked on samples of viruses grown in laboratories tested it on 192 human swabs of patients with pneumonia in hospital in Malaysia. Nine of these samples tested positive for coronavirus.
Further analysis showed that five of the nine samples were common human coronaviruses, which can cause colds. Surprisingly, four of the samples were canine coronavirus. Further studies on patients from the same hospital found four other positive patients.
The researchers examined nasal and throat swabs from all eight Malaysian patients to learn more about the coronavirus in dogs. Samples were placed on dog cells in the laboratory to see if a live virus was present. Virus from a single sample replicated well and virus particles could be seen using electron microscopy. The scientists were also able to sequence the genome of the virus.
Analysis found that this canine coronavirus was closely related to a number of different alphacoronaviruses – including those found in pigs and cats – and showed that it had not previously been identified anywhere else.
No signs of further spread
Was the canine coronavirus responsible for the pneumonia in the patients? Right now we just can’t tell. Seven out of eight patients were simultaneously infected with another virus, either adenovirus, influenza, or parainfluenza virus. We know that all of these viruses can cause pneumonia on their own, so it’s more likely that these were responsible for the disease. We can say that there is an association between pneumonia and canine coronavirus in these patients, but we cannot say that this is the cause.
There were concerns that the canine coronavirus identified in these Malaysian patients could spread from person to person, leading to a larger outbreak. How many Headlines It is not clear that these infections actually occurred in humans in 2017 and 2018. This further reduces the likelihood of an outbreak of canine coronavirus from this source, as there has been no evidence of further spread in the past three to four years.
As coronaviruses become the focus of attention and we look for related viruses, we will inevitably find more positive samples in unexpected places. The vast majority of these will only be of academic interest and need not sound the alarm. However, it is important that monitoring for new coronaviruses is continued and expanded so that we have the best possible chance of identifying significant cross-species jumps in the future.