How monkeypox transmits from person to person, and how to prevent infection

• Monkeypox has been confirmed in 81 countries where it wasn't typically found, including the US.
• An unusual monkeypox outbreak started in May — particularly among men who have sex with men.

Monkeypox has been confirmed in 81 countries where it wasn't typically found, as part of an unusual outbreak that started in May — particularly among men who have sex with men.

In parts of west and central Africa where the monkeypox virus is endemic, humans are most often exposed through contact with wild animals: either via bites and scratches, or during the preparation of bush meat.

Cases of monkeypox have been reported in the US and Europe before, historically in connection with travel to Africa or contact with imported animals.

However, since May there were 26,864 confirmed monkeypox cases and the vast majority were reported in countries where monkeypox wasn't endemic, according to the Centers for Disease Control and Prevention.

On July 23, the World Health Organization declared the 2022 outbreak was a global emergency — meaning an "extraordinary event" requiring a more robust global response.

On Thursday, the US federal government said monkeypox was a national public health emergency, which enables faster access to treatment and testing in the country. Since the first case of monkeypox was confirmed in the US in mid-May, there have been 7,102 reported cases in the US, mostly in New York, CDC data shows.

Monkeypox lesions are very infectious

Human-to-human monkeypox transmission can occur through prolonged face-to-face, skin-to-skin, mouth-to-mouth or mouth-to-skin contact, according to the WHO.

Once monkeypox gets into humans, the virus causes flu-like symptoms including fever, aches, and exhaustion, as well as a red rash that turns into pus-filled boils.

"You have lesion material — pus, scabs — all those legions are chock full of a ton of virus, and that virus is extraordinarily stable," CDC epidemiologist Andrea McCollum told Insider. "The virus is a double-stranded DNA virus, which by nature, it's really hearty."

As the boils burst and crust over, the infection can spread through direct contact with the lesions. The scabs it creates are very, very infectious, and can even be transmitted on a blanket or bed sheet through direct contact or inhaling infectious skin flakes.

As it stands, people are considered no longer contagious when all skin lesions have fully healed and new skin has appeared underneath, but we are still learning exactly how long people with monkeypox remain infectious for.

It is not clear if people without symptoms can spread the disease.

Getting intimate counts as close contact

Direct contact includes intimate contact such as hugging, kissing, touching contaminated sex toys and massage, according to the CDC. Sexual orientation has nothing to do with it.

Genetic material from the monkeypox virus has been detected in semen, but we don't yet know if the virus can spread through semen, vaginal fluids, breastmilk or blood, according to the WHO.

Sharing air with an infected person may pose a risk

The virus can spread via large, exhaled droplets — like the spray of a cough or sneeze. The droplets that may carry monkeypox are much bigger than, for example, coronavirus particles, which are tiny, airborne, and can float around in the air. Monkeypox can't travel as far.

Transmission by droplet is most likely to affect close contacts of infected people, like household members and healthcare workers. According to the WHO, the longest documented chain of monkeypox transmission was six successive person-to-person infections.

However, we don't know exactly how monkeypox travels through air, and studies are underway to learn more.

Pregnant people can spread the virus to fetus

According to the WHO, pregnant people infected with monkeypox can pass the virus to the fetus, either after birth or through skin-to-skin contact.

Simple ways to prevent infection

Clinicians treating patients often wear gowns, gloves, eye protection, and face masks, but the disease is not so transmissible that people need to be in all-encompassing hazmat suits around infected patients.

"It's not like Ebola where you have wards full of patients," McCollum said. "You may see a few."

At home, the CDC recommends avoiding skin-to-skin contact with anyone with a monkeypox rash, as well as any items that an infected person has used.

Fortunately, monkeypox can be scoured off surfaces easily with bleach. The CDC also recommends regular hand-washing with soap and water, or an alcohol-based hand sanitizer, especially before eating and after toileting.

Until more is known about its spread through bodily fluids, the WHO recommends that people with monkeypox use condoms as a precaution for 12 weeks after they have fully recovered.

"It's a serious disease, and something to steer clear of and try to prevent," Jimmy Whitworth, an infectious disease expert at the London School of Hygiene and Tropical Medicine, told Insider.