by By Jennifer Rigby and Julie Steenhuysen
LONDON/CHICAGO (Reuters) – Scientists studying the new strain of mpox that has spread out of the Democratic Republic of Congo say the virus is changing faster than expected and often in areas that lack funding and equipment. by experts to track it properly.
That means there are many unknowns about the virus itself, its severity and how it is transmitting, complicating the answer, half a dozen scientists in Africa, Europe and the United States told Reuters.
Mpox, formerly known as monkeypox, has been a public health problem in parts of Africa since 1970, but received little global attention until an international outbreak in 2022, prompting the World Health Organization to declare it a global emergency. to announce health. That declaration expired 10 months later.
A new strain of the virus, known as clade Ib, has once again caught the world’s attention after the WHO declared a new health emergency.
The strain is a mutated version of clade I, a type of mpox spread through contact with infected animals that has been endemic in the Congo for decades. Mpox usually causes flu-like symptoms and pus-filled lesions and can kill.
Congo received more than 18,000 suspected cases of clade I and claded Ib mpox and 615 deaths this year, according to the WHO. 222 cases of clade Ib have also been confirmed in four African countries in the past month, as well as one case each in Sweden and Thailand in people with a history of travel to Africa.
“I am concerned that we are working blindly in Africa,” said Dr. Dimie Ogoina, an infectious disease expert at the Niger Delta University Hospital in Nigeria who chairs the WHO mpox emergency committee. He first raised the alarm about the possible sexual transmission of mpox in 2017, now a way for the virus to spread.
“We don’t understand our outbreak very well, and if we don’t understand our outbreak very well we will have difficulty tackling the problem in terms of transmission dynamics, the severity of the disease, the risk factors of the disease,” Ogoina said. “And I’m concerned that the virus seems to be mutating and producing new strains.”
He said it took clade IIb in Nigeria five years or more to evolve enough for continuous spread among humans, triggering the 2022 global outbreak. Clade Ib has done the same in less than a year.
STREAMING ‘MUST’
Mpox is an orthotopic virus, the same family that causes smallpox. Population-wide protection has declined since a global vaccine campaign 50 years ago, as vaccination stopped when the disease was eradicated.
Genetic sequencing of clade Ib infections, which the WHO considers to have emerged in mid-September 2023, shows that they have a mutation called APOBEC3, a signature of adaptation in humans.
The virus that causes mpox is usually relatively stable and slow to mutate, but APOBEC-driven mutations can accelerate viral evolution, said Dr. Miguel Paredes, who is studying the evolution of mpox and other viruses at the Fred Hutchison Cancer Center in Seattle.
“Every human to human case of mpox has this APOBEC signature of mutations, which means it’s mutating a little faster than we would expect,” he said.
Paredes and other scientists said the response was complicated by several mpox outbreaks occurring immediately.
In the past, mpox was mainly acquired through human contact with infected animals. That’s still pushing a rise in Congo in cases of clade I — also known as Clade Ia — likely in part due to deforestation and increased bushmeat consumption, the scientists said.
The mutated versions, clade Ib and IIb, can now essentially be considered a sexually transmitted disease, said Dr. Salim Abdool Karim, a South African epidemiologist and chairman of the African CDC mpox advisory committee. Most cases of mutated clade Ib are among adults, initially driven by an epidemic among female sex workers in South Kivu, Congo.
The virus can also spread through close contact with an infected person, which is likely to have been the case in clusters of children infected with clade Ib, particularly in Burundi and in the displacement camps of eastern Congo, where crowded living conditions may have with him.
Children, pregnant women and people with weak immune systems may be at greater risk of serious mpox disease and death, according to the WHO.
Clade I tends to cause more severe disease, with death rates of 4%-11%, compared to around 1% for Clade II. Ogoina said that data from the Congo indicates that few people have died from the new Ib variant, but he feared that some data is being mixed up.
More research is urgently needed, but three teams tracking mpox outbreaks in Africa say they cannot even access chemicals needed for diagnostic tests.
It is difficult to plan a response, including vaccination strategies, without this, the scientists said.
Karim said that about half of the cases in eastern Congo, where Ib is particularly prevalent, are only being diagnosed by doctors, without any laboratory confirmation.
Getting samples to labs is difficult because the health care system is already under pressure, he said. And around 750,000 people have been displaced amid fighting between the M23 rebel group and the government.
Many laboratories in Africa cannot get the supplies they need, said Dr. Emmanuel Nakoune, mpox expert at the Institut Pasteur in Bangui, Central African Republic, who also has clade Ia cases.
“This is not a luxury,” he said, but it is necessary to track deadly outbreaks.
(Reporting by Jennifer Rigby in London and Julie Steenhuysen in Chicago; Editing by Caroline Humer and Bill Berkrot)
