Monkeypox Outbreak: What We Know (& Don't Know) Right Now

Dr. Ashley Drews, an infectious disease physician at Houston Methodist answers five questions about monkeypox and the current outbreak below.

What is monkeypox?

Monkeypox is a viral infection caused by the monkeypox virus, which belongs to the genus Orthopoxvirus. It's a close relative to the variola virus, which causes smallpox.

"The native reservoir for monkeypox remains unknown, but is thought to likely be rodents," says Dr. Drews. "Monkeys and humans are incidental hosts, and monkeypox infection is typically acquired through contact with infected body fluids or bite."

The majority of monkeypox infections occur in regions where the virus is endemic, including several Central and West African nations.

"Less commonly, monkeypox can also occur in people who come into contact with infected people or animals from these endemic regions," Dr. Drews says.

Indeed, just last summer, a Texas resident traveling from Nigeria was determined to be ill with the monkeypox virus. It was the first case seen in the U.S. in almost 20 years — since an outbreak in 2003, when more than 70 people became infected after handling prairie dogs imported from Ghana. It was determined that the prairie dogs had been co-housed with infected rodents.

For now, the source of the current global outbreak isn't fully understood.

Officials have stated, however, that it's the first documented example of monkeypox spreading between people in a non-endemic setting and unrelated to travel to an endemic setting.

What are the symptoms of monkeypox?

Monkeypox is primarily characterized by a generalized rash with skin lesions. The rash is infectious.

"The lesions often begin on the face before spreading to other parts of the body," says Dr. Drews. "In the days prior to the rash, infected individuals experience non-specific flu-like symptoms, including fever, headache, fatigue and body aches."

The current outbreak seems to be behaving a little bit differently than prior cases, however.

"Many of the current cases have presented with rash starting in the groin or perianal area and sometimes the lesions have not spread to other parts of the body," according to Dr. Drews.

Of note, the CDC has confirmed that the strain of monkeypox currently spreading — the West African strain — is the milder of the two strains that exist. The Congo Basin (Central African) strain causes more severe illness.

That the current outbreak involves the milder strain may explain why, in several of the recent cases, rash has appeared without fever.

"The rash can be clinically confused with a sexually transmitted infection (STI), like syphilis or herpes, or also with chickenpox," Dr. Drews says.

Dr. Drews adds that anyone who develops an unexplained rash should be evaluated as soon as possible and avoid intimate or face-to-face contact with other people.

How do you get monkeypox virus?

Experts know a lot about how monkeypox spreads from the virus' traditional behavior in endemic regions.

"Person-to-person transmission occurs primarily through large respiratory droplets, requiring prolonged face-to-face contact," says Dr. Drews. "It can also occur by direct contact with body fluids or lesion material."

There are also reports of transmission by objects, such as shared blankets or towels. Those cases are rare.

People are considered infectious five days prior to onset of rash and continuing until the lesions have crusted and separated, and a fresh layer of skin has formed underneath. This typically takes between two to four weeks.

The lesions, which carry the most virus, are the most infectious aspect of the illness. However, they also can reside in the mouth — explaining how the virus can spread via large respiratory droplets.

"This transmission is markedly different from COVID-19, which spreads through small droplets that in just a short period of time can infect others who are several feet away or through fine respiratory droplets that can hang in the air," explains Dr. Drews.

Experts are still learning about how exactly monkeypox is spreading during this particular outbreak, though. Some evidence suggests that large respiratory droplets may not be the primary mode of transmission in this case.

Anyone can develop and spread monkeypox illness, but many of the people affected in the current global outbreak are those who identify as gay and bisexual men.

"There is no clear evidence, however, that it's sexually transmitted," says Dr. Drews. "But as mentioned, it can be spread from person-to-person via personal, intimate contact, which includes sexual contact."

Is monkeypox deadly?

The reported fatality rate of the West African monkeypox strain — the one currently circulating — is around 1%.

"Most people recover in two to four weeks without specific treatment," says Dr. Drews.

That being said, anyone who notices an unexplained rash should be checked out by a health care provider.

"Evaluation isn't just important for recovery, it's needed to confirm a diagnosis — which is a critical step in containing the virus," says Dr. Drews. "Your doctor can advise you on the steps you need to take to prevent spreading the illness to your loved ones and others in your community."

Plus, while the West African monkeypox strain isn't likely to cause severe illness in most people, there's still more to be learned about who's most at risk for serious complications — such as those who are immunocompromised.

If needed, there are also tools that health care providers can use to help control the outbreak.

"There is no FDA-approved treatment for monkeypox, but antivirals used for smallpox have been used in individual monkeypox cases in the past," Dr. Drews adds. "There are also two vaccines that can be considered." 

What can you do to protect yourself from monkeypox?

The CDC has asked health care providers to be on the lookout for presumptive cases of monkeypox, but it's also important for you to be aware of your individual risk.

"Awareness is critical for making informed decisions," says Dr. Drews.

Here are five key takeaways:

• If you have a new or unexplained rash, seek medical care
• Any time a person has a rash, they're considered infectious
• Anyone can get monkeypox, but a notable proportion of recent cases have been reported in men who have sex with men
• Monkeypox is not an STI in the typical sense, but it can be spread by intimate contact
• If you have a rash and reason to suspect you may have monkeypox, don't hesitate to share your concerns with your health care provider

August 9, 2022