In May, when monkeypox began to spread across Europe and beyond, many public health specialists were taken by surprise. But for researchers who have tracked and studied the viral disease for years in central and western Africa, the only shock was how accurate their predictions were.
“We had always warned that under favorable circumstances, like what led to this outbreak, the disease could pose a great threat to global health,” Adesola Yinka-Ogunleye, an epidemiologist at the Nigeria Center for Disease Control (NCDC) told AFP. Abuja, who led the investigation and the country’s response to a monkeypox outbreak in 2017.
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Today, with over 80,000 confirmed cases in over 100 countries, monkeypox is a stark reminder of what happens when such warnings are ignored. Scientists such as Yinka-Ogunleye and epidemiologist Anne Rimoin, who has worked on monkeypox outbreaks in the Democratic Republic of Congo (DRC) since 2002, have accumulated decades of experience studying the spread of the virus. Their work on the ground has helped inform the global response, but much remains to be discovered. “There are a lot of questions we need to answer,” says Rimoin, who is based at the University of California, Los Angeles (UCLA).
Nature spoke with the two researchers to understand how the virus took hold in Africa and what can be done to stem its spread and prevent future global outbreaks of the disease.
In September 2017, Yinka-Ogunleye and her team traveled to Bayelsa in southern Nigeria to investigate the occurrence of mysterious rashes in people that defied treatment. The team suspected that the rashes were due to monkeypox – a virus related to smallpox, which causes smallpox. But the country had not recorded a case of monkeypox for about 40 years; it was a condition that doctors and medical students of the time had never encountered. Based on the symptoms they were seeing, the researchers first had to rule out smallpox.
However, the tests could not be carried out in Nigeria and would take several weeks. In the meantime, news of their investigation leaked and the public began to be alarmed about a possible health crisis. The pressure was mounting for the NCDC team to say something, even without all the facts. So the scientists decided to go on the radio and discuss their suspicion that monkeypox was the cause. They advised people to come forward if they were experiencing symptoms.
The bet is successful. Not only were they right about monkeypox, but their public posts revealed additional cases in the community. In one year, they identified 122 confirmed and probable cases, and 7 deaths. Nearly 70% of cases were in men, many of whom were adults, suggesting that the immunity conferred by the smallpox vaccine in the 1980s was on the decline in this group. The team also learned why monkeypox suddenly seemed to be reappearing in Nigeria after so long – it turns out the disease never really went away.
“We discovered at the time that we may have missed some cases before 2017,” Yinka-Ogunleye says. One of the dermatologists who spoke to the NCDC team described similar cases she had managed, but never considered monkeypox as the cause. The team concluded that the virus was likely endemic to Nigeria1.
Yinka-Ogunleye pushed for improved monitoring of the disease in humans and identification of possible animal reservoirs. “She has done a lot to coordinate the national response. We learned a lot from her,” says Odianosen Ehikhamenor, Incident Manager at NCDC’s Monkeypox Emergency Operations Center. Meanwhile, after working in the field for nearly a decade, Yinka-Ogunleye is studying for a PhD in epidemiology and global health at University College London.
Monkeypox in the DRC has followed a different trajectory than in Nigeria. The strain circulating in the DRC is from a “clade” of the virus that is deadlier than that of Nigeria and the rest of the world, and the DRC’s health infrastructure is less robust due to ongoing conflict. The country has seen thousands of suspected cases of monkeypox and hundreds of deaths from the disease each year since the 1980s. In 2022 so far, the country’s Ministry of Health has reported more than 4,500 suspected cases and confirmed and 155 deaths. Although the DRC lacks sufficient laboratory resources to confirm most cases, Rimoin has been working to change this for two decades.
She came to the field by an unexpected route. “I was a student of African history,” she says. “My thesis was on the assassination of Patrice Lumumba, the first Prime Minister of the DRC. As she learned more about the country’s culture and politics, she became interested in ways to help people there.
After graduating in history, she did a master’s in public health that led to a doctorate in epidemiology at the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland. From there, she dedicated herself to working on emerging infectious diseases with colleagues in the DRC. Her goal, she said, was to collaborate with and support “these amazing scientists.”
Monkeypox in Africa: the science the world ignored
Since 2002, Rimoin has been actively involved in helping health workers and researchers in the DRC to improve testing, surveillance and research, while helping officials in other countries and regions of Africa through the program UCLA-DRC Health Research and Training Center that she founded. The initiative trains epidemiologists from the United States and the DRC to conduct infectious disease research in low-resource and logistically complex settings.
“She is a good scientist with extensive field experience, particularly on monkeypox,” explains Placide Mbala, head of epidemiology and global health at the National Institute for Biomedical Research in Kinshasa. “Unlike other foreign collaborators,” he says, “she’s very open to new ideas and suggestions.”
When news broke of imported cases of monkeypox in the UK, Rimoin said she was not surprised. She has often warned that the world is susceptible to this virus, due to the halt in smallpox vaccination programs. (Unlike smallpox, monkeypox cannot be eradicated due to the existence of animal reservoirs.) She frequently discussed how the virus could spread beyond Africa.2,3.
With monkeypox now considered a global public health emergency by the World Health Organization, Yinka-Ogunleye and Rimoin say there has never been more need for studies on the extent of the disease in Africa. . Monkeypox is endemic in at least eight countries, including Benin, Cameroon, Ghana and Liberia, and cases have been reported in these and other countries across the continent during the current global outbreak.
Yinka-Ogunleye says studies of seroprevalence – the number of people who have antibodies against the virus – are a key priority for understanding the true extent of the epidemic in Nigeria and across Africa. This would reveal the proportion of people who have been exposed, she says.
Yinka-Ogunleye and Rimoin agree on the need for more support for disease surveillance, including laboratory diagnostics. In the DRC, it is difficult, if not impossible, to transport samples from wherever cases occur to a major city like Kinshasa.
Rimoin is also calling for better resources to help unravel the epidemiology and ecology of the virus in all endemic regions.
“There are still a lot of things we need to understand,” she says. This includes the duration of immunity from previous exposures to monkeypox, risk factors for poor outcomes, the nature of human-to-human transmission, and the stability of the virus on surfaces in different settings. Rimoin says that while there’s a long way to go, she hopes her network of collaborators and the rollout of additional studies will accelerate progress. “We hope to get answers,” she said.
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