Two novel arenaviruses detected in pygmy mice, Ghana

Abstract

Two arenaviruses were detected in pygmy mice (Mus spp.) by screening 764 small mammals in Ghana. The Natal multimammate mouse (Mastomys natalensis), the known Lassa virus reservoir, was the dominant indoor rodent species in 4 of 10 sites, and accounted for 27% of all captured rodents. No rodent captured indoors tested positive for an arenavirus.

Keywords: Ghana; Lassa fever; Lassa virus; Murinae; Rodentia; Western Africa; arenaviruses; emerging communicable diseases; epidemiology; pygmy mice; reservoirs; viruses; west Africa; zoonoses.

Figure 1

Lassa virus risk map of Ghana showing 10 numbered study sites adapted from Fichet-Calvet and Rogers, Model 3 (1). Red areas indicate high predicted risk for Lassa fever and green areas indicate low predicted risk. Solid black lines and letters indicate vegetation zones: a) Guinea savanna woodland; b) moist semideciduous forest; c) tropical rainforest.

Figure 2

Phylogenetic trees depicting virus sequences found in rodents from the villages of Jirandogo and Natorduori, Ghana. Lineages of Lassa virus clade are indicated by Roman numerals on the right. For each virus, phylogenetic trees are shown for 3 genes: 2a, glycoprotein gene (partial 1,034 bp), 2b, nucleoprotein gene (partial 1,297 bp), and 2c, Polymerase gene (L partial, 340 bp). The analysis was performed using PhyML (11), with a general time reversible nucleotide substitution model and 100 bootstrap replicates. Branches highly supported by PhyML are indicated with bootstrap values >50. Scale bars indicate nucleotide substitutions per site.