Serological Survey in African Nonhuman Primate Species in Cameroon and the Democratic Republic of the Congo Reveals Low Overall Seroprevalence to Mpox Virus.

Abstract

The mpox outbreak in August 2024 in central Africa, together with the mpox pandemic in 2022 associated with the emergence of new viral lineages in urban areas, highlighted that this historically neglected zoonotic tropical disease caused by mpox virus (MPXV) is of public health concern. The majority of mpox infections are of zoonotic origin, but knowledge on the animal reservoir of MPXV is still extremely limited. Nonhuman primate (NHP) samples (n = 1571) from 29 different species, collected across Cameroon and the Democratic Republic of the Congo (DRC), were tested for the presence of IgG antibodies with a peptide-based multiplex mpox serological assay. According to stringent or less-stringent cutoff used, 17 to 85 animals (1.1%-5.4%) had antibodies to at least 1 of the 3 peptides used. Seropositive samples were observed in 7 to 15 species, including Cercopithecus sp (C. ascanius, C. cephus, C. mitis, C. nictitans, C. neglectus, C. pogonias), Cercocebus sp (C. torquatus, C. agilis), Colobus sp (C. angolensis, C. guereza), Papio anubis, Lophocebus albigena, Mandrillus sphinx, Allenopithecus nigroviridis, and Pan troglodytes. Mpox seroprevalence was higher in Cameroon than in DRC (1.7%-8.5% vs 0.2%-0.9%; P < .01 to P < .001, respectively). Seroprevalence differed also according to sampling sites. In several sites, more than 1 NHP species was seropositive. Mpox seroprevalence differed, but not significantly, in arboreal (1.2%-5.4%; 15-69/1267), semiterrestrial (1.1%-4.3%; 1-4/92), and terrestrial species (0.5%-5.7%; 1-12/212). The low overall seroprevalence suggests that NHPs are most likely intermediate hosts and may be infected by other species, including reservoirs. However, they remain a potential source of human infection.