Health officials are perplexed by a recent outbreak of monkeypox, an unpleasant virus that can cause fluid-filled blisters on the skin. So far, doctors have detected around 80 cases of the disease around the world, including in England, Canada, Spain, Portugal, Sweden, Italy, France and the United States, but they’re not sure how or why it’s spreading, reports NPR’s Michaeleen Doucleff.
Though the case count is small, health officials are concerned that the virus could be spreading through a novel, as-yet-undetected mode of transmission. People typically contract the disease by coming into contact with an infected animal’s bodily fluid. Despite the name, it typically gets transmitted by rodents, not monkeys, in West or Central Africa, per NPR. Once the virus reaches a human host, it’s not a particularly contagious disease and is typically only spread via close contact with bodily fluids, such as saliva or pus from the pox.
These recent cases are a mystery because most of the patients had not recently visited Africa, nor did they have contact with anyone who traveled there. Evidence may also suggest that the virus is spreading via sexual contact, which is “a novel route of transmission that will have implications for outbreak response and control,” as Mateo Prochazka, an epidemiologist with the UK Health Security Agency, tweeted this week. Some of the cases occurred among people who self-identify as men who have sex with men, according to the Centers for Disease Control and Prevention.
Researchers detected the first case of monkeypox in 1958, when two outbreaks spread among monkeys used for research, according to the CDC. The first human case of the disease occurred in the Democratic Republic of the Congo in 1970. In the years since, it’s primarily been found in central and western African nations, including Cameroon, Central African Republic, Cote d’Ivoire, Gabon, Liberia, Nigeria, Republic of the Congo and Sierra Leone, though the majority of infections remain in the Democratic Republic of the Congo.
Symptoms in humans are similar to those of smallpox: In addition to the signature pox, the virus causes fever, headaches, muscle aches, fatigue, back pain and chills, per the CDC. It also causes the lymph nodes to swell, which is a major difference from smallpox. The lesions typically form on the face, then spread to other parts of the body. Eventually, they dry into scabs and fall off.
Overall, the illness persists for two to four weeks. In Africa, it kills as many as 10 percent of people who become infected, per the CDC. There is no treatment for monkeypox, but vaccines, antivirals and vaccinia immune globulin can be used to help control outbreaks, the CDC says.
Though just two suspected cases have been detected so far in the U.S., health officials were already on high alert. The CDC is encouraging doctors to be on the lookout for any unusual rashes among patients, regardless of their recent travel history or sexual encounters.
“This is very different than what we typically think of from monkeypox,” Jennifer McQuiston, a veterinarian and the CDC’s deputy director of high consequence pathogens and pathology, tells STAT’s Helen Branswell. “We have a sense that there might be some unusual methods of transmission, through intimate contact or some form of close personal contact that we’ve not previously associated with monkeypox.”Still, because of how uncommon monkeypox is, health officials say there is no public health risk. At a news briefing in Massachusetts, where a man who had recently traveled to Canada came down with the disease, Paul Biddinger, Mass General Brigham’s chief preparedness and continuity officer, said people should "be aware of symptoms but not be afraid,” as reported by CNN’s Nadia Kounang and Jennifer Henderson.