Concurrent Clade I and Clade II Monkeypox Virus Circulation, Cameroon, 1979–2022
Délia Doreen Djuicy, Serge Alain Sadeuh‐Mba, Chanceline Ndongo Bilounga, Martial Yonga, Jules Brice Tchatchueng‐Mbougua, Gael Dieudonné Essima, Linda Esso, Inès Manda Emah Nguidjol, Steve Franck Metomb, Cornelius Chebo, Samuel Mbah Agwe, Placide A. Ankone, Firmin N.N. Ngonla, Hans Makembe Mossi, Alain Georges Mballa Etoundi, Sara Eyangoh, Mirdad Kazanji, Richard Njouom
Abstract
During 1979-2022, Cameroon recorded 32 laboratory-confirmed mpox cases among 137 suspected mpox cases identified by the national surveillance network. The highest positivity rate occurred in 2022, indicating potential mpox re-emergence in Cameroon. Both clade I (n = 12) and clade II (n = 18) monkeypox virus (MPXV) were reported, a unique feature of mpox in Cameroon. The overall case-fatality ratio of 2.2% was associated with clade II. We found mpox occurred only in the forested southern part of the country, and MPXV phylogeographic structure revealed a clear geographic separation among concurrent circulating clades. Clade I originated from eastern regions close to neighboring mpox-endemic countries in Central Africa; clade II was prevalent in western regions close to West Africa. Our findings suggest that MPXV re-emerged after a 30-year lapse and might arise from different viral reservoirs unique to ecosystems in eastern and western rainforests of Cameroon.