A new study suggests that the monkeypox virus has mutated at a much faster rate than would normally be expected and probably underwent a period of “accelerated evolution.”
The virus, which has infected more than 3,500 people in 48 countries since its detection outside Africa in May, it may be more infectious due to dozens of new mutations. In total, the virus carries 50 new mutations not seen in previous strains detected between 2018 and 2019, according to a new study published June 24 in the journal. Natural Medicine (opens in a new tab). Scientists usually don’t expect it virus such as monkeypox to get more than one or two mutations each year, the study authors noted.
Monkeypox is a rare disease that virologists believe can circulate naturally in monkeys and rodents. Orthopoxvirus, comes from the same family and genus as smallpox virus, which causes smallpox, and does not usually spread far beyond West and Central Africa, where it is endemic. This year, however, the first widespread outbreak of the disease spread beyond Africa, shocked scientists and led the World Health Organization (WHO) to begin considering whether to classify the outbreak as global health emergency.
Strains of monkeypox virus can be classified into two clades, or lineages, known as the clades of West Africa and the Congo Basin. according to STAT. Viruses in each clade carry different mortality rates; the clade of West Africa has a mortality rate of about 1%, while the clade of the Congo Basin kills about 10% of those infected. The ongoing outbreak appears to be driven by the West African clade, STAT reported.
Related: Monkeypox Outbreaks: Here’s everything you need to know
Like a big double chain DNA virus, monkeypox is much more capable of correcting replication errors than a RNA viruses such as HIV, which means that the current strain of monkeypox should only have accumulated a handful of mutations since it began circulating in 2018. But after collecting DNA from 15 viral samples of smallpox of the monkey and reconstruct their genetic information, the researchers found that smallpox. the mutation rate was six to 12 times higher than expected.
The massive jump in the monkey virus mutation rate “is much more than would be expected given previous estimates of the Orthopoxvirus replacement rate,” the researchers wrote in the article. “Our data reveal additional clues about ongoing viral evolution and possible human adaptation.”
Historically, monkeypox is transmitted from person to person through close skin contact with open skin lesions, body fluids, contaminated material, or airborne coughing drops. But the unprecedented speed of new infections could suggest that something may have changed about how the virus infects its hosts, and new mutations could be a possible cause.
Many of the mutations identified by the researchers also carry revealing clues that may have arisen due to the virus’s contact with humans. immune system, specifically a family of enzymes that fight viruses called APOBEC3. These enzymes attack viruses by forcing them to make mistakes when they copy their genetic code, an act that normally causes the virus to break down. However, sometimes the virus survives the encounter and simply picks up some mutations in its genetic code, according to STAT. These types of battles may have happened repeatedly and caused the virus to pick up many mutations in a short period of time, the researchers theorized.
The mutation rate of the virus increased in 2018 and there are some explanations as to why it did. It is possible that the virus has been circulating in humans, at low levels, since then, picking up a lot of new mutations through its struggles with enzymes. Alternatively, the virus may have spread among animals from non-endemic countries without us realizing it for quite some time, and this year it has suddenly returned to humans.
Or it is possible that after a smallpox outbreak in Nigeria affected Nigeria in 2017, the virus spread mainly to African countries, evolving rapidly as it moved among smaller communities before re-emerging in non-endemic countries. this year.
Despite its name, monkeypox is most commonly transmitted to humans from rodents, of which African rope squirrels, striped mice, giant bag rats, and brush-tailed porcupines are the species that they are believed to be the main reservoirs of the disease. according to the Centers for Prevention and Diseases.
The last time monkeypox was so widespread in the United States was in 2003, when 71 people became infected with the West African clade after a shipment of infected Gambian rats, imported into Texas from of Ghana, transmitted the disease to dogs in local meadows.
A direct treatment for smallpox has not yet been tried, but doctors are administering to patients antiviral drugs and antibodies extracted from people immunized with the smallpox vaccine. Transmission is also reduced if people have the smallpox or smallpox vaccine, which allows scientists to prevent further infections by inoculating close contacts from an initial case, a strategy known as “ring vaccination” that caused the smallpox eradication in 1980.
Originally published in Live Science.