Emerging Infectious Diseases (Mar 2024)

Concurrent Clade I and Clade II Monkeypox Virus Circulation, Cameroon, 1979–2022

  • Delia D. Djuicy,
  • Serge A. Sadeuh-Mba,
  • Chanceline N. Bilounga,
  • Martial G. Yonga,
  • Jules B. Tchatchueng-Mbougua,
  • Gael D. Essima,
  • Linda Esso,
  • Inès M.E. Nguidjol,
  • Steve F. Metomb,
  • Cornelius Chebo,
  • Samuel M. Agwe,
  • Placide A. Ankone,
  • Firmin N.N. Ngonla,
  • Hans M. Mossi,
  • Alain G.M. Etoundi,
  • Sara I. Eyangoh,
  • Mirdad Kazanji,
  • Richard Njouom

DOI
https://doi.org/10.3201/eid3003.230861
Journal volume & issue
Vol. 30, no. 3
pp. 432 – 443

Abstract

Read online

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.

Keywords