LISBON (dpa-AFX) – According to a study, the causative agent of the current monkeypox epidemic has changed surprisingly strongly. Compared to related viruses of 2018 and 2019, there are about 50 differences in the genome, writes a Portuguese team in the journal “Nature Medicine”. This is much more than would have been expected based on previous estimates for this type of pathogen – about 6 to 12 times more. The divergent branch can be a sign of accelerated evolution. The work is mainly based on the analysis of Portuguese cases.
So far, experts had talked about a substantially rather slow development with regard to this type of virus, especially compared to the numerous mutations of Sars-CoV-2.
The study authors suspect one or more imports from a country where the virus is permanently present behind the current outbreak. Superspreader events and international travel therefore seemed to have promoted further dissemination. “Our data provides further evidence of ongoing viral evolution and possible adaptation to humans,” writes the team led by Joao Paulo Gomes of the National Institutes of Health Dotor Ricardo Jorge (INSA) in Lisbon.
Virus evolution expert Richard Neher (Basel) explained that the mutation rate was “indeed surprisingly high”. Mutations have a very specific pattern. The authors suspected that human immune system enzymes were responsible for these changes in the genome.
“Even in the current outbreak, we are seeing 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 this genome is about seven times smaller. However, such mutation rate comparisons are not very meaningful and say little about the evolution relative mutability of viruses outside.
When asked whether the mutations made it possible for the current to spread in the first place, the scientist explained that, to his knowledge, there were no indications to that effect, but he could not be ruled out. Most of the mutations “probably wouldn’t have a dramatic effect.”
As Neher describes, many laboratories have now analyzed the genome of monkeypox cases: most of these sequences belonged to the cluster described in the study.
About 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 as of May, there have been 3308 cases, according to information from the US health authority CDC as of Wednesday just before midnight CEST./ggr/ DP / zb