While the number of mpox, the infectious disease formerly known as monkeypox, cases in the U.S. is still relatively low, it's climbing.

You're likely wondering how concerned you should be.

"Right now, mpox is still not a huge public health concern for the general public as a whole," says Dr. Ashley Drews, an infectious disease physician at Houston Methodist. "However, close attention and communication is needed in communities where the virus seems to be most predominant. Most, but not all, current cases have been seen in men who have sex with men. The reason for this is unclear at this time."

Dr. Drews answers six questions about mpox and the current outbreak below.

What is mpox?

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

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

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

"Less commonly, mpox 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 mpox 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.

The source of the current global outbreak isn't fully understood, but it is behaving differently — with the predominant mode of person-to-person spread being from close intimate contact with someone who's infected.

Officials have also stated that this is the first documented example of mpox spreading between people in a non-endemic setting and unrelated to travel to an endemic setting.

What are the symptoms of mpox?

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

"The lesions characteristically begin on the face before spreading to other parts of the body," says Dr. Drews. "In the days prior to the rash, infected individuals can 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 mpox 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.

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

Anyone who develops an unexplained rash should be evaluated as soon as possible and avoid intimate or face-to-face contact with other people," warns Dr. Drews.

How do you get mpox virus?

Experts know a lot about how mpox 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 mpox 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 mpox 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 mpox deadly?

The reported fatality rate of the West African mpox 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 mpox 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 mpox, but antivirals used for smallpox have been used in individual mpox cases in the past and are available for high risk cases," Dr. Drews adds. "There are also two vaccines that can be considered."

Which states is mpox in?

"The first case of mpox in the U.S. this year was confirmed in Massachusetts," says Dr. Drews.

Additional cases have since been reported in most states — New York, California, Texas and Florida being most prevalent. So far, there are 131 confirmed cases in Houston, TX.

"Isolation and contact tracing are key to containing this illness, so it's important for those who think they may be showing signs of infection to seek medical care," says Dr. Drews.

What can you do to protect yourself from mpox?

The CDC has asked health care providers to be on the lookout for presumptive cases of mpox, 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 mpox, but a notable proportion of recent cases have been reported in men who have sex with men
• Mpox 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 mpox, don't hesitate to share your concerns with your health care provider

This was last updated May 20, 2024 to reflect the new nomenclature of the mpox virus.