Monkeypox originated in animals. Could this affect them?


two months later the international epidemic of monkeypox which, so far, has nearly 6,000 infections in the United States and over 18,000 cases in the world, it is perhaps old to say that this disease has already visited the United States. In 2003, the virus arrived via exotic pets imported from Ghana, sickening 72 people, including children as young as 3 years old. He sent 19 people to hospital before the outbreak died down.

Looking back, the obvious lesson seems to be how much monkeypox has changed its behavior since then. In 2003, every case could be attributed to a person’s exposure to an infected animal. In 2022, transmission appears massively person to person, attributable to sexual or skin-to-skin contact in men who have sex with men. But there is one key detail in the 2003 outbreak that worries researchers examining this news. Two decades ago, the virus spread because it passed from captured African wildlife to American animals sold as pets. These pets, wild prairie dogs, transmitted the virus to humans.

No one had considered such a cross-species vulnerability because human monkeypox infections had not previously been detected outside West and Central Africa. At the time, it was understood that African wildlife transmitted disease to people who hunted them or lived in their territories. What was surprising was that the virus could be transmitted to wildlife in other continents. It remains a cautionary tale – and it may be a warning that the virus could establish itself in new animal populations, now that it has spread to nearly 80 countries.

It is by no means certain. But it’s quite worrying that virologists are talking about the possibility of new host species in new territory – a spread that could constitute a “return” from humans to animals, creating new risks of exposure beyond what is currently known. Scientists are exploring this carefully; no one wants to be incendiary. “I don’t think there have been any cases at this point that are clearly due to zoonotic spread,” says Angela Rasmussen, virologist and associate professor at the Vaccine and Infectious Disease Research Organization-International Vaccine Center at the University of Saskatchewan. “And I think that would be separate, because we would see cases popping up unrelated to an MSM sex ring, and that hasn’t happened yet.”

Since several rodent species harbor monkeypox in the countries where it was first identified, it’s a safe bet that several species could be vulnerable to it elsewhere. But there is not enough accumulated science to unravel the implications. Could European or American wildlife briefly contract the disease and then defeat it? Or would it become a lingering infection among them? If it were to become endemic in wild animal populations, whether prairie dogs in the countryside or rats in cities, could it be passed on to other species that mingle with them? And how close should any of these animals be to people to pose an infectious risk or to be endangered by human contact?

“What I take away from the 2003 experience is that there is a wide range of species that may be susceptible to monkeypox,” says Jason Kindrachuk, a microbiologist and assistant professor at the University of Manitoba, who studies monkeypox and other zoonotic pathogens. “But we don’t quite understand what that looks like yet.”


Comments are closed.