Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: thedoc on 15/11/2016 11:58:01
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Heath Jackson asked the Naked Scientists:
Why don't dogs catch a cold? Bertie, our flat cost retriever, loves swimming even in icy ponds in winter but he never catches a chill and even though we re sneezing all over him. Is there anything we can learn from this?
What do you think?
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Firstly, dogs do have their own version of a "cold", but it's not caused by the same disease-causing agent as in humans. In humans, the common cold is typically caused by a rhinovirus. Rhinoviruses are generally highly host species specific, meaning that they can infect their natural host (eg. human), but they aren't very good at infecting animals of other species. Therefore, humans cannot infect dogs with their own colds, no matter how disgusting their coughing and sneezing habits are.
Dogs, as far as we currently know, do not have their own rhinovirus. However, they can commonly get respiratory infections which resemble the cold in humans. The most common syndrome that occurs is referred to as "kennel cough" (also called kennel cough complex and canine respiratory disease complex). Kennel cough is caused by either one of, or a combination of, a group of viruses and bacteria that are spread from dog to dog. The usual viruses are canine parainfluenza virus, canine adenovirus 2, but others may be involved. Almost all of the viruses are specific to dogs and cannot infect humans. The most common bacteria to be involved is Bordetella bronchiseptica (related to Bordetella pertussis, which causes whooping cough in humans), but this very rarely infects humans. The "kennel" part of the name refers to the environment in which this coughing syndrome was most often observed, historically, because dogs are most likely to be exposed to viruses and bacteria when there is mixing with lots of other (often stray and unvaccinated) dogs. Luckily, vaccines that protect against the common disease agents, and prevent disease spread, are now widely available.
As for swimming in icy ponds in winter, it really doesn't make a difference to the risk of "catching a cold" as long as the dog is not exposed to any disease agents (if disease carrying dogs are absent). If the body is REALLY stressed by cold or other factors, then it might become more susceptible to infectious diseases that are around but given the opportunity, a Bertie would likely leave the icy water before his immune system becomes compromised.