Mapping global zoonotic and interregional transmission of mpox

Mpox is a zoonotic disease that infects humans and other animals with the monkeypox virus (MPXV) endemic to Western and Central Africa. In 2022 and 2023, an outbreak of human mpox in more than 100 non-endemic countries led to 127 deaths. More recently, at least 450 people have died during another, more severe outbreak caused by a different MPXV variant.

This retrospective observational study has gathered all available historical case reports, outbreak investigations and surveillance studies to assemble a worldwide database of MPXV infections. The authors have documented a total of nearly 50,000 human mpox cases from 78 countries.

Using 525 full-genome sequences of MPXV obtained from GenBank, assembled and aligned to a reference genome, they created a phylogenetic tree, revealing two major viral clades associated with human infection: the Congo Basin clade (I) and the West African clade (II). The 2022-23 global outbreak of mpox was caused by a clade II variant, while a clade I variant is responsible for the recent upsurge in Central and East Africa.

To create a zoonotic transmission risk model, the authors used GBIF-mediated occurrences to map rodent richness and distribution for two reservoir species, Graphiurus lorraineus and Graphiurus crassicaudatus, then combined them with four climatic variables. The model predicted high risks of human MPXV infection in 28 African countries, highlighting the Democratic Republic of Congo as home to the largest at-risk area and population.

By analyzing global airline travel patterns, the authors predict that cross-border mpox cases are most likely to arise from endemic countries such as Nigeria, Ghana and Côte d'Ivoire, while Western European countries—in particular, the United Kingdom, Spain and Germany—face the highest likelihood of importing human mpox cases.