In recent days, even as we start to move on from the pandemic, we’re starting to hear of a sudden and unusual spike in cases of another exotic infectious disease. Here in the UK, there are clear signs of local transmission, leading to frantic detective work by the health authorities to locate and isolate possible cases. But while we’re all being soberly told that this infection is endemic to west Africa and is spread from animals, have you ever wondered – is it just monkeys and humans who are at risk? Are our pets safe?

What is monkeypox?

Monkeypox is a member of a wide family of viruses called the orthopoxviruses. You’ve probably heard all the media reporting that it is very closely related to smallpox, which indeed it is. However, that is at least in part because we’ve all heard of and are scared of smallpox so the phrase has resonance. Describing Monkeypox as “a close relative of camelpox” or cowpox or horsepox wouldn’t have the same impact! 

However, as the names of these other viruses suggest, orthopoxviruses have a range of natural hosts, and most of them are quite happy to jump the species barrier. In cats, for example, “Feline Orthopoxvirus” (a fairly common and seasonal condition in Europe, including the UK, usually spread by voles) is in fact our old friend Cowpox.

So sadly, yes. These viruses spread relatively easily between species, and so there is at least potentially a risk to our pets.

What animals can be infected?

While all the orthopoxviruses share some common characteristics, the different species are also distinct in their behaviours. The good news is that we have been unable to find any conclusive evidence of previous infections in dogs or cats. This may be because no-one has looked for it, of course. But it does suggest that carnivores aren’t a good host for this particular type – although there has now been one case report in a dog, following prolonged contact with a symptomatic human, so this may not apply to the new strain that is spreading in 2022.

However, that’s where the good news comes to an end, because sadly, Monkeypox seems to be very much at home in rodent species. The 2003 outbreak in the USA was caused by infected Prairie Dogs, who contracted the virus from imported African rodents. Specifically, researchers found that two African giant pouched rats, nine dormice, and three rope squirrels were infected with monkeypox virus. And subsequently transmitted it to the Prairie Dogs they were housed near; who went on to infect humans they came into contact with. It is likely that at least some species of rodent are capable of transmitting the infection to humans as well as becoming infected from humans, with white mice being the most vulnerable.

However, research has also shown that guinea pigs and hamsters are functionally immune to Monkeypox infection.

On the other hand, rabbits are known to be highly susceptible to Monkeypox; and when young, to be capable of transmitting the virus to other rabbits. However, it isn’t clear what role, if any, rabbits have in transmitting the infection to humans. In the well-studied 2003 outbreak, rabbits were not found to pose a risk to human health.

And finally, if you have pet primates (monkeys and marmosets, for example) they are of course susceptible, probably as much as humans are.

How ill do infected animals become?

It depends on a number of factors, including how they are infected, what route they are exposed to the virus through, how old they are, their health status, and of course what species they are.

Non-human primates

The most common symptoms are of a rash, looking very similar to the human condition. Young and infant animals are at higher risk of complications or more severe disease, but these can occur in animals of any age. In these cases, nasal discharge, loss of appetite, mouth ulcers and swelling, and sometimes difficulty breathing may be seen.

Rodents and rabbits

When infected, these animals usually develop a fever, sore eyes (conjunctivitis), respiratory signs (coughing and a runny nose), and non-specific signs such as lethargy and poor appetite. 

Many infected animals make a full recovery, but severe complications, that may lead to death, do occur.

How much of a risk is it really?

Right now, we don’t know for sure. However, we do know that domestic animals can spread related viruses to people. So it seems logical that we can spread the virus to them. However, at this point in time, all the transmission seems to be human to human, with little or no role for animals in the UK outbreak at least. 

So while the risk is there of infecting your animals – or even being infected by them – it is a very, very small risk compared to picking it up from another person. There’s certainly no reason to avoid contact with your animals unless you are already ill, or a high risk contact.

What should I do if I think my pet may be infected?

Contact a local vet and advise them that you are concerned that the animal may have monkeypox. This will allow them to put in place appropriate protective measures when they examine them. Most animals with a fever and sore eyes will have something unrelated. But it is always best to be cautious until we know more about the impact of this virus.

And what should I do if I think I may be infected?

Contact your health provider to notify them that you are concerned that you might be infected, and seek medical attention. Most suspect cases prove to be other conditions, but given the current situation, caution is appropriate!

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