Nature Medicine: Monkeypox virus seems to be accelerating evolution Portuguese researchers analyzed the genome of monkeypox virus (MAPX) outbreaks in multiple countries and found that these samples clustered together, indicating that they had a single source. According to the World Health Organization, more than 2,500 laboratory-confirmed monkeypox cases have been reported worldwide from the beginning of this year to mid-June, most of which were reported in the past two months. More than 80% of the cases were reported from Europe and 12% from the Americas, whereas most of these cases had no known association with endemic areas. Researchers recently carried out phylogenetic analysis of 2022 MPXV and found that this outbreak may have a single source and is associated with a large-scale epidemic in Nigeria in 2017. They report in Nature Medicine that viral samples appear to be accelerating evolution, which may be affected by host APOBEC3, a host antiviral mechanism. "Accelerated evolution is an observation, but we do not yet know how this occurs," said senior author João Paulo Gomes of the Portuguese National Institute of Health. It was completely unexpected to find so many mutations in 2022 MPXV. " Gomes and colleagues analyzed their first 2022 MPXV genome released on May 19, as well as 14 other MPXV genome sequences, most of which were also from Portugal. Phylogenetic analysis placed all samples from the 2022 outbreak in clade 3, the part formerly called the "West African" clade. All samples clustered tightly together, suggesting a single source of the outbreak. At the same time, these samples also formed a clade that differed from the viruses carried by the UK, Israel, and Singapore cases in 2018 and 2019. This suggests that the epidemic in 2022 may have resulted from the continued spread and evolution of the Nigerian virus. However, the monkeypox virus in 2022 differed by an average of 50 SNPs from the 2018/2019 virus, which Gomes believes is much more than expected. He says for this type of virus, one or two mutations are expected each year. Because the 2022 virus is the "descendant" of the 2017 Nigerian virus, they expect approximately 5 to 10 mutations, rather than 50. "Therefore, there is no doubt that we are facing accelerated evolution," Gomes said. The researchers point out that these changes also tend to follow a pattern that incorporates more adenine A and thymine T into already A/T-rich viral genomes, suggesting that the human APOBEC3 system may be involved in this accelerated evolution. APOBEC3 is a host antiviral mechanism that can induce viral mutations and has the potential