Cases in West and Central Africa have been on the rise for decades.
As monkeypox fuels pandemic fear in a pandemic-weary world, some African researchers are experiencing déjà vu. Another neglected tropical disease of the poor is discovered only after it infects people in rich countries. “It’s as if your neighbor’s house is on fire, and you just close your window and pretend everything is fine,” says Yap Boum, a Cameroonian epidemiologist who works for the health ministry as well as Doctors Without Borders.
The flames are now spreading. Monkeypox, which causes smallpox-like skin lesions but is rarely fatal, first appeared in the UK on May 7. More than 700 suspected and confirmed cases had been reported from every continent except Antarctica as of May 31. It is the largest outbreak seen outside of Africa and is primarily affecting men who have sex with other men, which was previously unknown. Public health officials and scientists are working around the clock to figure out how the virus spreads and how to stop it, with a focus on Africa’s long history with the disease.
“We’re all connected,” says Boum. “What happens in Africa will almost certainly affect what happens in the West, and vice versa.”
Monkeypox is an endemic disease in ten West and Central African countries, with dozens of cases reported this year in Cameroon, Nigeria, and the Central African Republic (CAR). The Democratic Republic of the Congo (DRC) has by far the highest burden, with 1284 cases in 2022 alone. Those numbers are almost certainly inflated. Infections are most common in remote rural areas of the Democratic Republic of the Congo, and armed conflict has hampered surveillance in several Central African Republic regions.
Despite being named after being discovered in a laboratory in Copenhagen, Denmark, in 1958 in a colony of Asian monkeys, the virus has only been isolated from a wild monkey once—in Africa. It appears to be more common in squirrel, rat, and shrew species, infiltrating the human population on occasion, where it spreads primarily through close contact but not through breathing. Isolating infected individuals usually hastens the end of an outbreak.
Over the last three decades, cases in Sub-Saharan Africa have steadily increased, owing largely to a medical triumph. The smallpox vaccine, which protects against a far deadlier and more transmissible virus, also protects against monkeypox, but it was discontinued in the 1970s, just as smallpox was declared eradicated. “A huge, huge number of people are now susceptible to monkeypox,” says Placide Mbala, virologist and head of the genomics lab at Kinshasa’s National Institute of Biomedical Research (INRB).
According to Mbala, demographic shifts have also contributed to the rise. “People are increasingly moving to the forest to find food and build houses,” he says, “which increases wildlife-human contact.” According to research in the Central African Republic, cases increase during the rainy season when villagers go into the forest to collect caterpillars for sale. “They easily get in contact with the animal reservoir when they stay in the bush,” says virologist Emmanuel Nakouné, scientific director of the Pasteur Institute of Bangui, which launched the Afripox programme with French researchers in 2018 to better understand and combat monkeypox.
The West African strain has been implicated in every outbreak outside of Africa, including the current one, and kills approximately 1% of those infected. The Congo Basin strain, found in the DRC and the Central African Republic, is ten times more lethal, but it has never left Africa, despite the DRC’s relatively high disease burden. However, it has never caused a major outbreak in a Congolese city, highlighting the isolation of the endemic areas. Mbala describes it as “almost like a self-quarantine.” “Those people do not migrate to other countries from the Democratic Republic of the Congo.”