Monkeypox virus phylogenetic similarities between a human case detected in Cameroon in 2018 and the 2017-2018 outbreak in Nigeria

Abstract

A monkeypox virus was detected from a human clinical case in 2018 in Cameroon; a country where no human cases were reported since 1989. The virus exhibited close genetic relatedness with another monkeypox virus isolated in Nigeria during the 2017-2018 outbreak. Although our molecular findings argue in favor of an extension of the monkeypox outbreak from Nigeria into Cameroon, the possibility that the monkeypox virus detected could be indigenous to Cameroon cannot be ruled out.

Keywords: Cameroon; Monkeypox virus; Phylogenetic relationships; West African clade.

Fig. 1

Phylogenetic relationships of the studied monkeypox virus isolate recovered from current infection in Cameroon. The phylogenetic tree was based on the multiple alignment of 639 nucleotides partial sequences of the A-type Inclusion (ATI) gene [nucleotides 126,536 to 127,174 according to sequence isolate 298,464 originating from Nigeria in 2017 (GenBank N° MG693724)]. Phylogenetic analysis was performed by the Maximum Likelihood method with the best-fit model identified by Smart Model Selection using the Bayesian Information Criterion (Lefort et al., 2017): Tamura-Nei with gamma-distributed rate heterogeneity and 4 rate categories (TN93 + G + Γ4). The studied and reference monkeypox virus isolates from Cameroon are highlighted by red circle (●) and red triangles (▲), respectively. The year and country of isolation of databases available isolates are indicated (DRC: Democratic Republic of the Congo; USA: United-States of America). The reliability of individual tree nodes was estimated using 1000 bootstrap pseudoreplicates and values less than 60% have been omitted. The scale bars indicate nucleotide evolutionary distance as substitutions per site. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)