A dog has been infected with monkeypox for the first time after sharing a bed with its infected owners, scientists have said.
It is the first reported case of a domesticated dog or cat catching the virus and comes as the virus continues to spread worldwide in people.
Two gay men living in Paris developed monkeypox symptoms at the start of June and went to a hospital, where their lesions were identified as being caused by the disease.
The non-exclusive couple, aged 44 and 27-years-old, developed sore lesions in their anal region as well as over the rest of their body a week after having sex with other men.
Twelve days after the men went to the Pitié-Salpêtrière Hospital in Paris with their symptoms, their otherwise healthy four-year-old male Italian greyhound developed lesions too, with pustules on the stomach and a “thin anal ulceration”.
A PCR test revealed the dog had monkeypox, and genetic sequencing found it was a 100 per cent match to the strain that infected his owners, indicating the dog caught the virus from his owners.
Paris, like other Western European capitals including London and Madrid, has been the epicentre of its country’s monkeypox outbreak as the virus spreads almost exclusively via the sexual networks of gay men.
The lesions are themselves laden with infectious material and prolonged close contact is needed for it to spread from one individual to another.
Sexual contact between people is one medium, but not the only way it can be transmitted. For example, healthcare workers have previously caught the virus after handling the bedsheets of an infected person, and sharing a bed but not engaging in sexual activity is a high-risk activity.
The sharing of a bed between a pet dog and two infected individuals is against guidance, with experts urging people to quarantine away from their dog to reduce transmission risk.
“In endemic countries, only wild animals (rodents and primates) have been found to carry monkeypox virus,” the clinicians write in their letter to the Lancet, which was published last week.
“However, transmission of monkeypox virus in prairie dogs has been described in the USA and in captive primates in Europe that were in contact with imported infected animals.
“Infection among domesticated animals, such as dogs and cats, has never been reported.
“To the best of our knowledge, the kinetics of symptom onset in both patients and, subsequently, in their dog suggest human-to-dog transmission of monkeypox virus.”
Official guidance from British health authorities is that pet rodents (gerbils, guinea pigs, hamsters etc) of monkeypox cases must be isolated in a secure location, such as a government lab, for three weeks, as these animals are known to easily catch and spread monkeypox.
However, other pets like cats and dogs can be isolated at home, away from infected people, as it is very difficult for the virus to jump across the species barrier to dogs from people.
Prof Tom Wenseleers, a professor of evolutionary biology at KU Leuven in Belgium, said the fact the virus has infected a pet dog may mean the pathogen, which has infected around 3,000 people in the UK, has mutated recently to spread easier, and in a slightly different way.
“[This case] really makes me wonder if something did change with respect to the tropism and transmission patterns of the [monkeypox] lineage, either recently or since 2017,” he wrote on Twitter.
Defra assesses the risk of human to pet transmission as “low” and guidance published by the Animal and Plant Health Agency (APHA), an executive agency within Defra, recommends people not groom or stroke their pet, as well as avoiding their bedding, litter and food.