Monkeypox Outbreaks: 4 Key Questions Scientists Have

Monkeypox Outbreaks: 4 Key Questions Scientists Have thumbnail

It’s been three months since a case was confirmed by public-health officials in the United Kingdom. Since then, more than 400 confirmed or suspected cases have emerged in at least 20 non-African nations, including Canada, Portugal, Spain and the United Kingdom — the largest outbreak ever seen outside Africa. The situation has scientists on alert ,. Because the monkeypox virus is spreading in multiple populations, there is no obvious connection between the clusters. This raises the possibility of undetected local transmission.

” We need to act quickly, but there are still a lot of lessons to be learned,” Anne Rimoin, an epidemiologist from the University of California Los Angeles who has been studying monkeypox in the Democratic Republic of the Congo over a decade.

Nature outlines some of the key questions about the recent outbreaks that researchers are racing to answer.

How did the current outbreaks begin?

Researchers have sequenced viral genomes from monkeypox patients in several countries, including the United States, France, Germany and Portugal, since the outbreaks started. The most important insight they have uncovered so far is that each sequence closely matches that of a monkeypox virus strain found in West Africa. This strain is much less deadly than the Central African variant. It has a lower death rate than the one found in Central Africa. That one has a fatality rate of up to 10%.

Clues about the origin of the outbreak have also been revealed. Researchers still need to verify their suspicions but the sequences they have examined so far are almost identical. This suggests that an epidemiological investigation could reveal that all recent outbreaks in Africa are linked to one case.

The current sequences are most similar to those from a smattering of monkeypox cases that arose outside Africa in 2018 and 2019 that were linked to travel in West Africa. The simple explanation is that the non-African victim of this year’s first case was infected by the virus through contact with an animal or person carrying the virus, according to Bernie Moss, a virologist at National Institute of Allergy and Infectious Diseases (Bethesda, Maryland).

But there are other possibilities, says Gustavo Palacios a virologist at Mount Sinai’s Icahn School of Medicine in New York City. It is possible that the virus was already in circulation, undetected, in humans and animals outside of Africa, possibly because it was introduced during previous outbreaks. This is less likely, however, as monkeypox often causes visible lesions on the body. A physician would likely be notified.

Could a genetic mutation in the virus explain the recent outbreaks?

Understanding the genetic basis for the virus’s unprecedented spread beyond Africa will be difficult, according to Elliot Lefkowitz (a computational virologist at The University of Alabama at Birmingham who studies poxvirus evolution). Researchers are still struggling to determine precisely which genes are responsible for the higher virulence and transmissibility of the Central African strain compared with the West African one more than 17 years after they identified a difference between the two.

Lefkowitz states that this is because poxvirus genomes are complex. The monkeypox genome, which is six times larger than the SARS-CoV-2 genome, is huge relative to other viruses. This means that monkeypox genomes can be at least six times more difficult to analyse, according to Rachel Roper, a virologist from East Carolina University in Greenville.

Another reason is that very few resources have been allocated to genomic-surveillance efforts for Africa, where monkeypox was a public-health concern over many years. He says that virologists are still in the dark because they don’t have enough sequences to compare the new monkeypox strains. He adds that funding agencies have not heeded scientists who have warned for over a decade1 about the possibility of more monkeypox outbreaks.

Ifedayo Adetifa, head of the Nigeria Centre for Disease Control Abuja, said that many African virologists have expressed frustration at their inability to get funding and publish studies on monkeypox for years. But now that the virus has spread to other continents, public-health authorities around the world seem to be interested.

To understand how the virus evolves it would be helpful to sequence the virus in animals, Palacios states. Although the virus has been shown to infect rodents, mainly rats and squirrels, scientists have yet to find its natural reservoir in Africa.

Can the outbreaks of disease be contained?

Understanding the genetic basis for the virus’s unprecedented spread beyond Africa will be difficult, according to Elliot Lefkowitz (a computational virologist at The University of Alabama at Birmingham who studies poxvirus evolution). Researchers are still struggling to determine precisely which genes are responsible for the higher virulence and transmissibility of the Central African strain compared with the West African one more than 17 years after they identified a difference between the two.

If the vaccines were to be used, they would likely be used in a “ring vaccination” strategy that would inoculate close relatives of infected persons. Andrea McCollum, an epidemiologist at the CDC who heads the poxvirus group, said that the agency has not yet implemented such a strategy. CNN reports the United States intends to offer smallpox vaccinations to certain health-care workers who treat infected patients. Rimoin suggests that it might be worth considering vaccinating groups with a higher risk of infection and close contacts of infected persons.

Virologists are concerned about the possibility of monkeypox spreading to animals even if public-health officials manage to stop the spread in the current outbreaks. The possibility of monkeypox being transmitted to humans again and again in countries without any animal reservoirs would increase. On 23 May, the European Centre for Disease Prevention and Control highlighted this possibility, but deemed the probability “very low”. European health officials strongly recommend that pet rodents, such as hamsters or guinea-pigs, be kept away from people with confirmed cases. They can also be monitored in government facilities, or, as a last resort euthanized to avoid any spillover.

Although the risk is low, Moss said that scientists would not know if there was a spillover event until it was too late. Infected animals don’t usually show the same symptoms as humans.

Is this virus spreading differently than previous outbreaks?

The Monkeypox disease spreads through close contact with bodily fluids, lesions, and respiratory droplets from infected animals or people. But health officials have been examining sexual activity at two raves in Spain and Belgium as drivers of monkeypox transmission, according to the Associated Press, raising speculation that the virus has evolved to become more adept at sexual transmission.

The linking of cases to sexual activity does not mean that the virus has a higher spread rate or is more contagious. Roper states that poxviruses can survive outside of the body for longer periods than SARS-CoV-2. However, unlike SARS-CoV-2 which doesn’t seem to linger on surfaces, Roper says that poxviruses can survive outside the body for long periods. This makes surfaces like doorknobs and bedsheets potential vectors.

Health officials have noted that there have been many cases among men who have had sex with women (MSM), but Rimoin insists that the most likely explanation is that the virus was accidentally introduced to the community and has continued to spread there.

All of the attention given to monkeypox has revealed just how little scientists know about the virus, McCollum said. McCollum says, “When all of this has settled down, I think it will be time to think long and deeply about where the research priorities lie.”

This article is reproduced with permission and was first published on May 27 2022.

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    Max Kozlov is a scienc

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