More than a hundred confirmed cases of monkeypox in humans have been identified outside of African countries since early May.
Monkeypox cases outside of Africa are rare, so this outbreak has raised alarm bells around the world.
In spite of its name, monkeypox in humans doesn't really have much to do with monkeys. Here's the disease got its misleading name.
Why is it called monkeypox?
Humans aren't the only primates that can catch monkeypox. Monkeys can catch it too and that's where the disease got its name.
The virus that causes monkeypox was first spotted in 1958 among a colony of monkeys used for research imported to Denmark. The disease caused lesions that were similar to those seen in smallpox — a cousin of monkeypox — so the scientists called it monkeypox.
It was only much later, in 1970, that the first human case of monkeypox was identified.
"The name of this virus is a terrible misnomer. But we're not changing it today," expert Andrea McCallom told Insider.
McCallon is an epidemiologist with the US Centers for Disease Control and Prevention who has been investigating monkeypox outbreaks for years.
Are monkeys involved in human monkeypox?
The short answer is no: monkeys likely have nothing to do with the disease humans are getting.
Monkeypox is a zoonotic disease, which means that humans catch the virus from animals that are sick.
Humans are thought to only be exposed to the virus occasionally by close contact with the ill animals — for instance, through scratches or bites. Human-to-human transmission is known to happen but is thought to be rare.
We don't know exactly which species carry monkeypox in the wild. Scientists believe they are contained within west and central Africa.
This hypothesis is supported by an outbreak of monkeypox in the US in 2003. The cases were linked back to prairie dogs that had been exposed to a Gambian pouched rat imported from west Africa.
Why this latest outbreak is happening away from Africa or identifiable vector animals is unclear. Humans appear to be giving it to each other — part of what is concerning officials today.