LONDON – As more cases of monkeypox are discovered in Europe and North America, some scientists who have monitored several outbreaks in Africa say they are baffled by the disease’s unusual spread in developed countries.
Cases of smallpox-associated disease have not previously been seen among unrelated people in Central and West Africa. But in the past week, Britain, Spain, Portugal, Italy, the United States, Sweden and Canada have reported infections, mostly in young adults who have never traveled to Africa.
France, Germany, Belgium and Australia confirmed their first cases of monkeypox on Friday.
“I was stunned by this. Every day I wake up and there are more and more countries infected,” said Owewell Tomori, a virologist who formerly headed the Nigerian Academy of Sciences and a member of several WHO advisory boards.
“This is not the kind of spread we’ve seen in West Africa, so there may be something new going on in the West,” he said.
Monkeypox usually causes fever, chills, rash, and lesions on the face or genitals. The World Health Organization estimates that the disease is fatal to about 1 in 10 people, but smallpox vaccines are preventative and some antiviral drugs are also being developed.
According to Tomori, the outbreaks in Nigeria, which report about 3,000 cases of monkeypox annually, are usually in rural areas, where people come in close contact with infected mice and squirrels. He said the disease does not spread very easily and that many cases are likely to be missed.
Tomori hoped that the emergence of monkeypox cases across Europe and other countries would increase scientific understanding of the disease.
The WHO’s leader in emergency response, Dr Ibrahima Seuss Fall, acknowledged this week that there are still “many unknowns regarding transmission dynamics, clinical features (and) epidemiology”.
On Friday, Britain’s Health Security Agency reported 11 new cases of monkeypox, saying that a “significant proportion” of the latest infections in the UK and Europe were young men with no history of travel to Africa who were gay, bisexual or had sex with Men.
Authorities in Spain and Portugal said their cases were of young men who had mostly had sex with other men and said the cases were caught when the men showed up with lesions at sexual health clinics.
Experts stressed that they do not know whether the disease is spread through sex or other close contact linked to sex.
“It’s not something we’ve seen in Nigeria,” said virologist Tomori. He said viruses that were initially not known to be sexually transmitted, such as Ebola, were later shown to do so after large epidemics showed different patterns of spread.
Tomori said the same could be true for monkeypox. “We had to go back through our records to see if this happened, like between husband and wife,” he said.
In Germany, Health Minister Karl Lauterbach said the government was confident the outbreak could be contained. He said the virus was being sequenced to see if there were any genetic changes that might make it more contagious.
Rolf Gustafsson, professor of infectious diseases, told Swedish radio SVT that it was “very difficult” to imagine that the situation could get worse.
We will certainly find some other cases in Sweden, but I don’t think there will be an epidemic in any way. There is no indication of that at the moment.”
Scientists said that while it is possible that the first patient of the outbreak contracted the disease while in Africa, what is happening now is exceptional.
“We’ve never seen anything like what’s happening in Europe,” said Christian Happe, director of the African Center for Excellence in Infectious Disease Genomics. “We haven’t seen anything to say that monkeypox transmission patterns have changed in Africa, so if something different happens in Europe, Europe needs to investigate that.”
Happy also noted that suspending smallpox vaccination campaigns after the disease was eradicated in 1980 might inadvertently aid the spread of monkeypox. Smallpox vaccines also protect against monkeypox, but mass immunization was discontinued decades ago.
“Apart from people in West and Central Africa who may have had some immunity to monkeypox from previous exposure, not having received any smallpox vaccine means that no one has any kind of immunity to monkeypox,” Happy said.
Shabbir Mahdi, professor of vaccinology at the University of the Witwatersrand in Johannesburg, said a detailed investigation of the outbreak in Europe, including determining who the first patients were, is now critical.
“We need to really understand how this first started and why the virus is now gaining traction,” he said. “In Africa, there has been a highly controlled and infrequent outbreak of monkeypox. If this is changing now, we really need to understand why.”
Geir Molson in Berlin, Jan M. Olsen in Copenhagen, and Associated Press correspondents across Europe contributed to this report.