In recent years, a type of influenza virus known as H3N2 has been spreading among dogs, leading to a condition commonly referred to as “dog flu.” While the virus has primarily remained confined to the canine population, a new study from China suggests that it may evolve and adapt to better recognize human-like receptors. This raise concerns that the virus could eventually jump to humans and cause a pandemic.
A recent study published by eLife and reported by Popular Mechanics has highlighted concerns that the H3N2 avian influenza virus, which has been circulating in canines for the past decade, is showing signs of adaptation that allow it to better recognize human-like receptors. The study suggests that canines may serve as intermediates for adapting avian influenza viruses to humans, which is a cause for concern given the human population’s lack of immunity to the canine version of the virus.
The H3N2 virus first emerged in birds, which was highly contagious and often lethal. In 2006, it successfully jumped to dogs and has since stabilized within canine populations. The virus has been responsible for several canine influenza outbreaks in the US and Asia, and there is evidence that it is becoming increasingly widespread globally.
The H3N2 virus was also found in one out of every twenty sick canines assessed in the study. They also discovered that the virus’s genome has begun to resemble a human virus, implying that it is evolving to be more appropriate for its mammalian hosts. Mammals’ constant evolution generates concerns that they may one day constitute a threat to humans.
Even though the virus does not appear to pose a severe threat to canine health, changes in the virus signal that it is becoming better adapted to transmission among mammals. This could result in the virus effectively adapting to the mammal, especially if the animal also demonstrates symptoms of adaptation toward human transmission.
Ian Jones, a professor of virology at the University of Reading, believes that the virus’s development into something more known to mammals is expected, given the virus’s lengthy history in the dog population. That evidence for alarm has yet to be proven. Even though there is no pre-existing human immunity to canine influenza, the study recommends ongoing surveillance and risk assessments.
According to James Wood, head of the veterinary medicine department at the University of Cambridge, the long-term pandemic potential in other animals, including humans, is a concern. As he points out, it stands to reason that a virus circulating in dogs for so long would have developed to better transfer between mammals. Although avian flu still risks humans, the virus cannot be passed from person to person via the infected receptor molecule. But everything changes if the virus can adapt to a mammal and then show signs of adapting to human transmission.
Despite a steady increase in canine cases, no human infections have occurred. However, the study emphasizes the importance of ongoing surveillance and risk assessment to track the evolving threat of H3N2 canine influenza. The virus is continually evolving and adapting to its host, so people must be on the lookout for any signs that it may transmit to them.
