Monkeypox is a new global threat. African scientists know what the world is facing science

As monkeypox fuels fears here-we-go-pain in a pandemic-weary world, some researchers in Africa have their own sense of déjà vu. Another neglected tropical disease of the poor attracted attention only after it began to infect people in rich countries. “It’s like your neighbor’s house is on fire and you just close your window and say it’s okay,” said Jaap Boom, an epidemiologist in Cameroon who works with both the health ministry and Doctors Without Borders.

Now the fire is spreading. The global smallpox epidemic, which causes skin lesions similar to smallpox but not usually fatal, occurred on May 7 in the United Kingdom. As of May 31, more than 700 suspected and confirmed cases from every continent other than Antarctica have been reported. It is the largest outbreak outside of Africa and is concentrated among men who have sex with men, a phenomenon never seen before. Public health officials and scientists are struggling to understand how the virus is spreading and how to stop it – and are drawing new attention to Africa’s many years of experience with the disease.

“We are interdependent,” Bohm said. “What is happening in Africa will definitely affect what is happening in the West and vice versa.”

Monkeypox is endemic in 10 countries in West and Central Africa, with dozens of cases this year in Cameroon, Nigeria and the Central African Republic (CAR). The Democratic Republic of the Congo (DRC) has by far the largest burden with 1,284 cases in 2022 alone. These figures are almost certainly underestimated. In the DRC, infections most often occur in remote rural areas; in the CAR, armed conflicts in several regions are under limited surveillance.

The virus got its name after it was first identified in a colony of Asian monkeys in a laboratory in Copenhagen, Denmark, in 1958, but was isolated from wild monkeys – in Africa – only once. It appears to be more common in squirrels, rats and shrews, and is sometimes distributed in the human population, where it is spread mainly by close contact but not by respiration. Isolating infected people usually helps outbreaks end quickly.

Cases have steadily increased in sub-Saharan Africa over the past three decades, largely due to medical triumph. The smallpox vaccine, a far more deadly and portable virus, also protects against monkeypox, but the world stopped using it in the 1970s, shortly before smallpox was declared eradicated. As a result, “there are huge, huge numbers of people who are now susceptible to monkeypox,” said Placid Mbala, a virologist who runs the genomics lab at the National Institute of Biomedical Research (INRB) in Kinshasa, DRC.

Mbala says demographic change has also fueled the rise. “People are increasingly moving to the forest to find food and build houses, and this increases the contact between wildlife and the population,” he said. CAR studies show that the cases increase after villagers move to the forest during the rainy season to collect caterpillars that are sold for food. “Once left in the bush, they easily come into contact with the animal reservoir,” said virologist Emanuel Nakoune, research director at the Pasteur Institute in Bangui, who launched a program called Afripox in 2018 with French researchers to better understand and to fight monkeypox.

All outbreaks outside Africa, including the current one, include the West African strain, which kills about 1% of those infected. The Congo Basin strain, found in the DRC and CAR, is 10 times more deadly, but despite the relatively high severity of disease in the DRC, it has never left Africa. But it has never caused a serious outbreak in a Congolese city, highlighting the isolation of areas where it is endemic. “It’s kind of like self-quarantine,” Mbala said. “These people are not moving from the DRC to other countries.”

Overflow

The monkeypox virus infects squirrels, rats and shrews in at least 10 countries in West and Central Africa and occasionally jumps into the human population. So far this year, five countries have reported human cases.

(Graphics) K. Franklin /science; (Data) World Health Organization

Exactly where the current epidemic began and for how long is unclear. “It’s a bit like we’re involved in a new TV series and we don’t know which episode we got,” said Anne Remoin, an epidemiologist at the University of California, Los Angeles who has worked on monkeypox in the DRC for 20 years. The first patient with an identified case traveled from Nigeria to the United Kingdom on May 4, but did not appear to have infected anyone else. Two patients later diagnosed, one in the United States and the other in the United Arab Emirates, also recently traveled to Africa and may have imported the virus separately. But none of the other cases identified in recent weeks have involved infected travelers or animals from endemic countries. Instead, many early cases involved gay festivals and saunas in Spain, Belgium and Canada.

Some suspect the virus may have been imported from Nigeria, Africa’s most populous country, which has good infrastructure connecting rural areas with major cities and two airports that are among the busiest in Africa. But this is “highly speculative,” said Christian Happy, who heads the African Center of Excellence in Nigeria for the genomics of infectious diseases. Happi urges people in other countries “not to point the finger” but to cooperate.

Epidemiologist Ifedayo Adetifa, head of the Centers for Disease Control in Nigeria, says the country is receiving too much attention because it is monitoring more than its neighbors and shares what it finds. “For whatever reason, there is too much emphasis in Western capitals and in the news media on trying to hold someone responsible for a particular epidemic,” he said. “We don’t think these stories are useful.” Adetifa says that although there has been an “increase in cases” in Nigeria recently, he is convinced that he does not miss a large number of them. “We’re literally shaking the bushes to see what comes out.”

The virus is on the rise

In the 4 decades since the world stopped vaccinating against smallpox, the number of suspected and confirmed cases of monkeypox in Africa has steadily increased.

(Graphics) K. Franklin /science; (Data) EM Bunge et al., PLOS neglected tropical diseases16 (2): e0010141 (2022)

The ability of African countries to deal with monkeypox was improving even before the current epidemic. The DRC has stepped up surveillance in the vast country, which is key to isolating infected people and tracking virus movements. The INRB and a laboratory in Goma can now diagnose samples using polymerase chain reaction analysis, and researchers hope to eventually develop rapid tests for use in clinics across the country. The NRB and laboratories in Nigeria may also sequence the full genome of the virus, and Nigeria plans to make public genomes of several recent monkeypox isolates, Adetifa said. These and other sequences from Africa could help researchers determine the source of the international epidemic by building viral family trees.

There is currently a lack of drugs in Africa to prevent and treat monkeypox. In the United Kingdom and the United States, a high-risk contact case offers a vaccine made by Bavarian Nordic, which was approved for monkeypox by the US Food and Drug Administration in 2019, but is not available anywhere in Africa. The U.S. Centers for Disease Control and Prevention and DRC staff are testing the vaccine on health workers; the approval for 2019 is based on animal studies.

In the CAR, 14 people with monkeypox received an experimental drug, tecovirimate, as part of a study launched by Oxford University in July 2021. “We had very good results,” said Nakune, who said he expected the data to be published in the next few weeks. The drug’s manufacturer, SIGA, is committed to providing up to 500 courses of treatment to the country.

Although the international epidemic has once again highlighted global health inequalities, it has also drawn much-needed attention to the smoldering disease in Africa. “It was really difficult to get the resources to do this basic work, which really needs to be done and which is not far off, in the context of an emergency,” said Remoin. “We can’t keep pushing the delay button. Now the stakes are really high. ”

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