Exportation of Monkeypox Virus From the African Continent
Matthew R. Mauldin, Andrea M. McCollum, Yoshinori Nakazawa, Anna Mandra, Erin Whitehouse, Whitni Davidson, Hui Zhao, Jinxin Gao, Li Yu, Jeffrey B. Doty, Adesola Yinka-Ogunleye, Afolabi Akinpelu, Olusola Aruna, Dhamari Naidoo, Kuiama Lewandowski, Babak Afrough, Victoria Graham, Emma Aarons, Roger Hewson, Richard Vipond, Jake Dunning, Meera Chand, Colin Brown, Inbar Cohen-Gihon, Noam Erez, Ohad Shifman, Ofir Israeli, Sharon Melamed, Eli Schwartz, Adi Beth-Din, Anat Zvi, Tze Minn Mak, Yi Kai Ng, Lin Cui, Raymond Tzer Pin Lin, Victoria A. Olson, Tim Brooks, Nir Paran, Chikwe Ihekweazu, Mary G. Reynolds
Abstract
BACKGROUND: The largest West African monkeypox outbreak began September 2017, in Nigeria. Four individuals traveling from Nigeria to the United Kingdom (n = 2), Israel (n = 1), and Singapore (n = 1) became the first human monkeypox cases exported from Africa, and a related nosocomial transmission event in the United Kingdom became the first confirmed human-to-human monkeypox transmission event outside of Africa. METHODS: Epidemiological and molecular data for exported and Nigerian cases were analyzed jointly to better understand the exportations in the temporal and geographic context of the outbreak. RESULTS: Isolates from all travelers and a Bayelsa case shared a most recent common ancestor and traveled to Bayelsa, Delta, or Rivers states. Genetic variation for this cluster was lower than would be expected from a random sampling of genomes from this outbreak, but data did not support direct links between travelers. CONCLUSIONS: Monophyly of exportation cases and the Bayelsa sample, along with the intermediate levels of genetic variation, suggest a small pool of related isolates is the likely source for the exported infections. This may be the result of the level of genetic variation present in monkeypox isolates circulating within the contiguous region of Bayelsa, Delta, and Rivers states, or another more restricted, yet unidentified source pool.