Five Americans are likely infected with monkeypox, the Centers for Disease Control and Prevention said Monday, warning that people might first mistake the infection for a sexually transmitted disease.
Scientists have recorded more than 300 confirmed or suspected monkeypox cases, mainly in Europe, and are trying to determine if and how the cases might be connected.
For decades, monkeypox has been seen in parts of Central and West Africa, believed to jump occasionally from animals, probably rodents, into people. Typically, several travelers a year arrive in the U.S. and Europe infected with the virus, but such a large chain of person-to-person transmission has never been seen before.
Unlike most known cases of monkeypox, where the telltale rash usually appears first on the hands, among the current cases many rashes are first appearing around the genitals or anus, CDC officials said in an afternoon news conference with media.
MONKEYPOX EXPLAINER: What we know about 'atypical' surge in monkeypox cases in the US
With beach season kicking off this weekend, public health officials want to be sure that Americans and their health care providers are aware of the possibility that a rash plus travel history might indicate monkeypox rather than a more common sexually transmitted disease, like herpes or syphilis, which it can resemble.
Monkeypox is a viral illness in the same family as smallpox, though it's far less dangerous. It appears first as a flu-like illness, with fever, muscle aches and malaise, followed by skin lesions, though the rash may appear first, said Capt. Jennifer McQuiston, a veterinarian and deputy director of the CDC's Division of High Consequence Pathogens and Pathology.
Monkeypox is not as easily transmissible as viruses like SARS-CoV-2, which is responsible for the COVID-19 pandemic. A lesion in the mouth could lead someone to spew viral particles when talking or coughing, though it is not typically considered a respiratory virus.
Of nine known cases of people infected with the virus who traveled from Nigeria before the outbreak, none passed it on to others on the plane or through casual contact, McQuiston said.
"This is not an easily transmissible virus," she said. "This is not COVID."
There is no indication that these cases are any different genetically from earlier ones or that the virus is mutating to become anymore transmissible or dangerous, she said.
"There are really only a handful of cases in the United States right now," McQuiston said, adding that the CDC is doing surveillance to make sure it doesn't miss any others. "I don't think there's a great risk to the general community now in the United States."
Five Americans infected
Among the five Americans believed to be infected, all traveled internationally, apparently around the end of April, and became symptomatic in early May. All are men. One, who lives in Boston, was believed to have been infected in Canada.
McQuiston declined to release details about the others except where they live and to say their experiences were "consistent with the types of travel and exposures being reported globally." One is in New York City, another is in Broward County, Florida, and two are in Salt Lake City.
In Massachusetts, more than 200 people have been identified as having had some contact with the infected man, the vast majority of whom are health care workers, McQuiston said.
The virus is not considered a sexually transmitted disease, though it can be transmitted through close personal contact with sores or bodily fluids, such as what happens during sexual activity, said Dr. John Brooks, a medical epidemiologist with the CDC's Division of HIV/AIDS Prevention. Clothing and bedding can also become contaminated.
Many of the people infected in the outbreak identify as gay or bisexual, Brooks said, but "this is a virus that could affect anyone."
The CDC is concerned about the pace with which cases are developing worldwide and wants to raise awareness about symptoms without encouraging people to cancel events. "We want to raise everyone's attention and be very vigilant so we can try to control it as quickly as possible," Brooks said.
Most people infected with monkeypox recover on their own without treatment in two to four weeks, McQuiston said, though it can be lethal in rare cases. Lesions in the eye could cause vision problems, and lesions in the throat can cause breathing difficulties.
All of the reported cases are mild and appear to be going away on their own, she said.
The CDC is concerned about the possibility of someone who is immunocompromised becoming infected. A person with an immunocompromising or skin condition is likely to take longer to bring a monkeypox infection under control, Brooks said. Small studies suggest that people with HIV whose infection is under control are probably at the same risk from monkeypox as the general population, he said.
To determine whether someone is infected, local public health officials conduct a PCR test to identify whether the infection belongs to the orthopoxvirus family of viruses, which includes smallpox and monkeypox.
Then the sample is sent to the CDC, which has confirmed that the Massachusetts man is infected with monkeypox and found the genetic sequence of the virus to be similar to one identified in a patient in Portugal, McQuiston said. The other patients' samples were still being reviewed but presumed to be monkeypox, she said.
Vaccines and treatments
The United States has stockpiles of vaccines to prevent smallpox, which should also be effective against monkeypox, McQuiston said. Smallpox was eradicated worldwide in 1980, but concerns about a possible release, either intentional or accidental, have triggered national stockpiles of vaccines and the development of antivirals.
Two vaccines authorized for use against smallpox should also be effective against monkeypox, McQuiston said.
The U.S. has more than 100 million doses of ACAM2000, manufactured by Emergent Product Development. But that vaccine, which enables a harmless version of the virus to replicate in the body, can be dangerous for people who are immunocompromised or have skin conditions like atopic dermatitis or eczema, said Dr. Brett Petersen, a medical officer with the CDC.
A newer vaccine, Jynneos, given in two doses a month apart, was approved in 2019 for both smallpox and monkeypox. The U.S. has only about 1,000 doses available immediately, though "we expect that to ramp up very quickly," McQuiston said.
Only people at high risk for infection are expected to need vaccination.
Jynneos, which is made by Bavarian Nordic, has been shown to be safe among people with HIV and atopic dermatitis, Petersen said.
The national stockpile is providing doses of Jynneos for some of the people who came in close contact with the five American patients, including health care workers and family members, McQuiston said.
About half of Americans have some protection against monkeypox because they are old enough to have been vaccinated against smallpox. Smallpox vaccinations stopped in 1972.
No drug has been proven effective against monkeypox in people, but two antivirals developed against smallpox are likely to be, Petersen said.
Tecovirimat, also known as TPOXX, which prevents the virus from spreading among cells, was used to treat patients in a small monkeypox outbreak in the Central African Republic, but results have not yet been published, he said.
Brincidofovir, approved in 2021, which limits viral replication, has shown some effectiveness against monkeypox in animal studies, he said.
The world should be prepared to see more pox diseases as the population immunized against smallpox declines over time, Anne Rimoin, a professor of epidemiology at the UCLA Fielding School of Public Health, said in an interview.
“It makes sense as time goes on and the vast majority of the world has no immunity and people come into contact with the monkeypox virus that people will get infected,” said Rimoin, who has studied monkeypox and other infectious diseases in Central Africa.
“We’ve seen rodent-borne Alaska pox, mousepox in Europe, camelpox in India, cowpox in Brazil, because now the world is susceptible," she said. "We anticipate seeing more of this over time."
Contributing: Elizabeth Weise
Contact Karen Weintraub at firstname.lastname@example.org.
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This article originally appeared on USA TODAY: Monkeypox cases may be mistaken for a sexual transmitted disease: CDC