Monkeypox On The Rise: How Worried Should We Be?

Nov 16, 2017

Earlier this month, the Washington Post ran a big, feature about a seemingly scary disease, called monkeypox.

"It kills up to 1 in 10 of its victims, similar to pneumonic plague, and is particularly dangerous in children," the story observes at the beginning.

Plus, the virus appears to be on rise.

"Since 1970, 10 countries in Africa have had at least one recorded human case of monkeypox," the story says. A map shows the disease popping up across countries in West and Central Africa, including the Congo Republic, where the story takes place. The country is fighting an outbreak with 88 cases and six deaths, the World Health Organization says.

The story chronicles a thrilling hunt to find the source of monkeypox: Is it a giant pouched rat? An African brush-tailed porcupine?

And it put monkeypox at the forefront of national media. Even Fox News picked up on the idea and ran a segment entitled: "Monkeypox & Black Death Plague Resurface," read a headline for a Tucker Carlson segment. "It could reach this country before we know it's coming," Carlson said.

There's no question monkeypox can be a serious disease. It causes a fever, and a rash, which can turn into painful, fluid-filled blisters on the face, hands and feet.

But here at Goats and Soda, we wanted to know more. Where on Earth does this virus come from? And how dangerous is it compared to other threats, like Ebola or H7N9 bird flu?

To get the lowdown, we talked to two monkeypox experts: Anne Rimoin at the University of California, Los Angeles, who has studied monkeypox in the Democratic Republic of Congo for 15 years; and Jay Hooper at the U.S. Army Medical Research Institute of Infectious Diseases, who is working to develop a better monkeypox vaccine.

Here are some of the questions we asked and some of their surprising answers.

Where does it come from? Monkeys?

No!

"The name is actually a little bit of a misnomer," Rimoin says. Perhaps it should be called "rodentpox" instead.

Yes, monkeys can get monkeypox. But they aren't major carriers. Instead, the virus likely persists in squirrels or another rodent.

How do you catch it?

From an animal bite, scratch or contact with their bodily fluid. Then the virus can spread to other people through coughing and sneezing or contact with pus from the lesions.

"But it doesn't spread very well between people," Hooper says. "It's infection rate is much lower than that of smallpox." In many cases, people don't spread the virus to anyone else.

"There is no evidence, to date, that person-to-person transmission alone can sustain monkeypox infections in the human population," the World Health Organization writes.

Is there likely to be an outbreak in the U.S.?

"There already was!" Hooper says. "But it was quickly contained."

In 2003, monkeypox hitched a ride with a shipment of animals from Ghana to Illinois. Several giant pouched rats and squirrels tested positive for the virus and eventually spread it to prairie dogs, being sold as pets in multiple states in the Midwest, the Centers for Disease Control and Prevention writes.

Forty-seven people caught the disease from the prairie dogs. Everyone recovered. And no one spread the disease to another person.

Is monkeypox a "new" virus?

No. The virus has likely been infecting people for centuries, even millennia, Rimoin says. But for a long time, doctors missed the cases.

Monkeypox is closely related to smallpox. "They are clinically indistinguishable," Rimoin says. "So for centuries, doctors have likely mistaken monkeypox for smallpox."

Then in 1970s, the world was close to eradicating smallpox. Cases plummeted. And doctors in Central Africa started noticing another disease that looked like smallpox but didn't spread as well between people. It was monkeypox.

There are several other virus related to smallpox, including cowpox and camelpox. "I would be more worried about camelpox than monkeypox," Rimion says, "because that's closer on the genetic tree to smallpox."

Is the disease actually a rising threat? Or are just better at detecting it?

A little bit of both, Rimion says.

Back in 2010, Rimoin and her colleagues reported that monkeypox had increased 20-fold in the Democratic Republic of Congo since the 1980s. Incidence rose from less than 1 case per 10,000 people to about 14 cases per 10,000 people.

And the reason for this bump is ironic: The eradication of smallpox.

The smallpox vaccine actually works quite well to protect people against monkeypox. It's about 85 percent effective (although the vaccine does have some safety concerns, Hooper points out. "It's a live virus and cause a deadly infection in people with severely compromised immune systems.").

But after the world eradicated smallpox, countries stopped vaccinating kids. And for those who were vaccinated years earlier, their protection has likely waned over time, Hooper says.

"So now there's this growing population of people who don't have immunity to monkeypox," he says. "And when you do have a outbreak, it's likely to be bigger because less people in the community are protected."

That means small outbreaks in West and Central Africa now have dozens of cases instead of just one or two, Hooper says.

So is monkeypox one of the major viral threats worldwide?

"Nah," Hooper says. "Because the virus doesn't transmit very easily between people. If it did, then it would be top priority."

On average, a person sick with monkeypox spreads the virus to between zero and one person. So outbreaks burn themselves out quickly.

"You have primary cases, in which people get monkeypox from an animal, and they may transmit the disease a few generations — but then that's it," she says. "The outbreaks tend to be self-limiting."

Could that change?

"Oh yes," Hooper says. "Every time, there's an outbreak — and the more people get infected — the more chances monkeypox has to adapt to people," he says.

In other words, the more time the virus spends inside people, the more time it has to evolve. It could possibly figure out how to spread more quickly between people.

So scientists are keeping a close eye on the virus and these small outbreaks.

"We didn't think Ebola spread very easily between people," Hooper adds. "And we were all surprised that health care workers could catch it even though they were wearing protective gear."

"With viruses that spillover from animals, you just never know what's going to happen."

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