LISBON (dpa-AFX) – According to a study, the cause of the current monkeypox outbreak has mutated surprisingly strongly. Compared to related viruses from 2018 and 2019, there are about 50 differences in the genome, the team from Portugal writes in the journal “Nature Medicine”. This is much more than would be expected from previous estimates for this type of pathogen: about 6 to 12 times more. A diverging branch may be a sign of accelerated development. The work is based primarily on the analysis of Portuguese cases.
So far, experts have talked about the relatively slow development of this type of virus – especially compared to the very numerous Sars-CoV-2 mutations.
The authors of the study suspect one or more imports from a country where the virus is permanently present behind the current outbreak. Superspreader and international travel events then apparently encouraged further dissemination. “Our data provide further evidence of ongoing viral evolution and possible adaptation to humans,” writes a team led by Joao Paulo Gomes of the National Institutes of Health Doctor Ricardo Jorge (INSA) in Lisbon.
Virus evolution expert Richard Neher (Basel) explained that the mutation rate was “really surprisingly high”. Mutations have a very specific pattern. The authors hypothesized that enzymes of the human immune system are responsible for these changes in the genome.
“Even during the current outbreak, we are witnessing this accelerated mutation. The rate is about one mutation per genome per month.”
“With some uncertainty,” Neher said. Sars-CoV-2 has about two mutations per genome per month, but that genome is about seven times smaller.
Asked if the mutations even allowed simultaneous spread, the scientist explained that, to his knowledge, there was no evidence but that it could not be ruled out. Most mutations would “probably not have a dramatic effect.”
According to Neher, many laboratories have now analyzed the genome of smallpox cases – most of these sequences belonged to the cluster described in the study.
Around 5,000 cases of monkeypox have been reported in humans worldwide this year. In more than 40 countries outside Africa, where the disease was virtually unknown until May, 3,308 cases were reported on Wednesday shortly before midnight, according to the CDC.