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Rare monkeypox infections detected in several European countries

Pox viruses (shown here in this illustration) like monkeypox are oval-shaped with double-strand DNA.
(Image credit: ROGER HARRIS/SCIENCE PHOTO LIBRARY via Getty Images)

Seven cases of monkeypox have been confirmed in London and northeastern England, only one of which was linked to travel outside of the country, health officials said. Current evidence hints that the rare disease may now be spreading in the local community, according to the U.K. Health Security Agency (opens in new tab) (UKHSA).

This viral spread, if it is occurring, could potentially extend beyond the U.K. and affect people in other countries, U.S. health officials warned on Tuesday (May 17), according to STAT (opens in new tab). This concern was validated on Wednesday, when two more European countries announced suspected and confirmed cases of the disease, STAT reported (opens in new tab) on May 18. These countries include Spain, where eight potential cases are under investigation, and Portugal, where five cases have been confirmed and more than a dozen probable cases have been identified. 

Monkeypox is a rare infection caused by a poxvirus that belongs to the same family and genus as the variola virus, which causes smallpox, according to the Centers for Disease Control and Prevention (opens in new tab) (CDC). The infection initially causes symptoms of fever, headache, muscle aches, exhaustion and swollen lymph nodes; rashes then appear on the face and spread over the body, eventually giving rise to patches of discoloration, blisters, scabs and raised bumps on the skin. In Africa, where the disease is endemic, the infection is fatal in an estimated 10% of cases, but in the majority of cases, the illness remains mild and resolves in about two to four weeks.

Historically, cases of monkeypox outside of Africa have been linked to international travel or animal imports, according to the CDC. (African rodents and non-human primates can carry the virus.) However, the source of the six non-travel-related infections in the U.K. remains a mystery, and it's unknown whether the newfound cases in Spain and Portugal are related to the U.K. infections, according to STAT.

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"This is rare and unusual," Dr. Susan Hopkins, chief medical adviser for the UKHSA, said in the statement released Monday (May 16). "UKHSA is rapidly investigating the source of these infections because the evidence suggests that there may be transmission of the monkeypox virus in the community, spread by close contact." 

In general, the monkeypox virus does not spread easily between people but can enter the body through contact with broken skin, the respiratory tract or the mucous membranes of the eyes, nose or mouth, according to the CDC. Transmission between people is thought to occur mostly through large respiratory droplets, meaning drops of spit and mucus imbued with viral particles. 

"Respiratory droplets generally cannot travel more than a few feet, so prolonged face-to-face contact is required" for transmission to occur, the CDC said. However, people can also pick up the virus from contaminated objects, particularly clothing and linens, or by coming into contact with contaminated bodily fluids with broken skin.

Earlier in the month, on May 7, UKHSA reported a case of monkeypox that was linked to travel; in that case, the infected person picked up the infection while in Nigeria, the agency stated (opens in new tab). UKHSA worked with the National Health Service (NHS) to notify people who might have been in close contact with the infected person; they identified no additional cases through this investigation. 

Following the detection of this travel-related infection, the UKHSA identified two people in a London household who'd also contracted monkeypox; however, these infections were not linked to the initial travel-related case, UKHSA announced (opens in new tab) on May 14. Then, on May 16, the agency announced four more monkeypox cases — three in London and one in Newcastle — that had no known connection to any of the previous cases.

"Investigations are underway to establish links between the latest 4 cases, who all appear to have been infected in London," the UKHSA statement states. "All 4 of these cases self-identify as gay, bisexual or other men who have sex with men." So far, common contacts have been identified for two of these four cases. 

The overall risk of contracting the virus remains low amongst the general public, as again, the pathogen requires prolonged close contact to spread, according to the UKHSA statement. However, "we are particularly urging men who are gay and bisexual to be aware of any unusual rashes or lesions and to contact a sexual health service without delay," Hopkins said. 

(The Spanish news outlet El País (opens in new tab) reported that the eight suspected cases in Spain were intitially flagged at a clinic that treats sexually transmitted diseases.)

As the U.K. launched its investigation into the nation's monkeypox cases, CDC officials raised concerns that there may be multiple chains of transmission rippling through the country, only some of which have been detected, STAT reported.  

"You have two clusters that have no link to travel or to other people who are known to be associated with a recognized outbreak. It suggests that there are unknown chains of transmission happening," Dr. Jennifer McQuiston, a senior CDC official, told STAT earlier this week. "If there appears to be unknown chains of transmission, it just puts us on alert to be thinking: Could this be spreading outside the U.K.?" Now, there's reason to believe it is.

In anticipation of potential spread to the U.S., the CDC may issue an alert to health care facilities, and in particular, clinics that treat sexually transmitted diseases, to be on the lookout for potential monkeypox cases, McQuiston told STAT.

Originally published on Live Science.

Nicoletta Lanese
Staff Writer

Nicoletta Lanese is a staff writer for Live Science covering health and medicine, along with an assortment of biology, animal, environment and climate stories. She holds degrees in neuroscience and dance from the University of Florida and a graduate certificate in science communication from the University of California, Santa Cruz. Her work has appeared in The Scientist Magazine, Science News, The San Jose Mercury News and Mongabay, among other outlets.