Correction: A previous version of this story incorrectly identified a country where the new mpox strain has been recorded. The story has been updated.
A highly contagious and severe strain of mpox is on the move across continents following a major outbreak in central Africa.
The surge of cases in the Democratic Republic of Congo and a dozen other African nations prompted the World Health Organization last week to issue aglobal health emergency for the second time in two years. A day later, Swedish officials said they recorded their first case of the mpox virus.
While the new strain has yet to reach the United States, that doesn't mean U.S. health officials aren't preparing for that eventuality.
Here's what to know about mpox and the latest outbreak.
What is mpox?
Mpox, previously known as monkeypox, is a part of the same virus family that causes smallpox, according to the Centers for Disease Control and Prevention. It is not related tochickenpox.
Discovered in 1958, the virus was originally named monkeypox because that's the animal it was first discovered in,not because monkeys are the source of infections. However, the disease has in recent years been renamed to mpox to avoid the stigma that associated it with monkeys.
The disease is zoonotic, which means it can be spread fromanimalsto humans. However, it can also pass from person to person through physical contact,according to the CDC.
In fact, more human-to-human transmissions have beenreported since 2016, according to Politico.
There are two types of mpox – clade I and clade II. Clade I is endemic in central Africa, while clade II is endemic in West Africa. A new variant of clade I, called Ib, appears to spread more easily.
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Is there an mpox outbreak?
Congo and surrounding countries have had worsening outbreaks since 2023.
Just in 2024, central and eastern Africa have had over 17,000 infections and more than 500 people died from mpox, primarily in Congo, according to theAfrica Centres for Disease Control and Prevention. So far this year, mpox outbreaks have been recorded in 13 African nations, including the Democratic Republic of Congo, Uganda, Rwanda, Burundi and the Central African Republic.
That’s a significant increase of the 14,957 cases in 2023 and 7,146 cases in 2022.
Last Thursday,thefirst case was identified outside of Africa when it was revealed that a traveler from Sweden had returned from a trip to Africa carrying the disease.
The Africa CDC has reported 500 deaths and, amid concern of further spread, has asked for international medical help but issuing its own emergency declaration. The alert, known as a public health emergency of international concern, or PHEIC, is the highest level of alarm under international health law, WHO says.
About10 million vaccine dosesare needed for the outbreaks in Africa, according to the Center for Infectious Disease Research and Policy at the University of Minnesota.
The U.S. said it would donate 50,000 vaccine doses to Congo. However, experts predict that millions more will be needed from Western countries, particularly the U.S., to help stop the virus. To make this happen, vaccine manufacturers will have to increase production dramatically.
Is mpox in the US?
Meanwhile, U.S. officials are preparing for the eventual arrival of the new mpox strain here.
But in an alertlast week, the CDC said the spread in the U.S. was a “very low risk" at this time.
The CDC has also issued ahealth alertandtravel noticeabout the stronger mpox strain in Congo and neighboring countries, recommending providers and health agencies monitor for signs and ask patients about recent travel to affected areas.
While a few cases of the less severe strain of the virus are still reported each week in the U.S., those cases are from a different strain of mpox, clade II from a 2022 outbreak, Reuters said.
Mpox in graphics:What to know after WHO declares global emergency
What happened with mpox in 2022?
This new strain of mpox is a little different than the one that has circulated in the U.S. since a global outbreak began in 2022.
The clade II strain had largely been contained to the African continent until Spring 2022, when it suddenly appeared in Europe and then the United States. The first cases were detected in the United States in mid-May that year, and by Aug 1, the peak was reachedwhen 638 cases were reported.
Most of the outbreak was driven by cases in major cities, particularly New York, Los Angeles and San Francisco at a time when social events were happening in the summer, such as Pride month. An emergency declaration for the outbreak in the United States came to an end on Jan. 31, 2023.
Since 2022, the U.S. has had outbreaks of clade II mpox, mostly among men who have sex with men, but also in some nonbinary and transgender people, according torecent CDC data. Overall, more than 32,000 people in the U.S. have been infected and 58 have died of mpox.
However, Mpox clade I is considered not only more easily transmissible, but more severe. It has infectedtens of thousands of people, including children, sex workers and workers in health care settings who lack proper protective equipment.
How is mpox spread?
Mpox often spreads through bodily fluids and physical contact, theCenters for Disease Control and Prevention (CDC)said.
The disease usually passesto humans from rodents and primates, through bites, aerosol transmissionor contact with infected fluids. Person-to-person transmissionis usually through close contactwith respiratory secretions, inflected skin lesions or recently contaminated objects, according to the WHO.
What are symptoms of mpox?
Infection is usually mild, but the mpox illness can last anywhere from two to four weeks and can prove fatal if left untreated.
Most symptoms are similar to the flu, and can also include pus-filled skin lesions.
Within one to three days of infection, a patient will develop a facial rash that spreads to other parts of the body – including hands, feet, chest, face, mouth and genitals – the CDC said. The rash can start out as a pimple or blisters and over time can become very painful.
The fluid-filled lesions go through a series of stages before drying out and falling off.
Theincubation period, the time betweeninfection andsymptoms, is usually 6 to 13 days but can be 5 to 21 days.
Other symptoms of mpoxinclude:
- Headache and fever
- Swollen lymph nodes
- Exhaustion
- Body chills
- Backache and body aches
- Rash over the body
- Blister-like lesions resembling chickpox that begin as small bumps
What is the treatment for mpox?
Vaccines are available and recommended for people from higher-risk populations.
The approved JYNNEOS vaccine, a two-dose series administered at least four weeks apart, provides protection against both clade I and clade II.
The vaccine is highly effective, a recent CDCreportshowed. Fully vaccinated people became infected in less than 1% of cases. And for those who did, infections were milder compared to unvaccinated people.
While more than 75% of at-risk populations in the U.S. have not been fully vaccinated against mpox, many people who get their first shot of the mpox vaccine do not return for their second dose.a CDC analysis found.
Contributing: Karen Weintraub, USA TODAY; Reuters
Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at elagatta@gannett.com
