Spatiotemporal dynamics of rabies virus detected in rabid dogs in Cameroon, 2010–2021

Rabies is a viral zoonosis that causes an estimated 60,000 human deaths each year, mainly in Africa and Asia. The etiological agent of rabies, the Rabies Lyssavirus or Rabies Virus (RABV) has been characterized in dog populations in Cameroon, in previous studies. However, the dynamics of RABV maintenance and propagation in dogs are still to be documented in Cameroon. This study thus, aimed at investigating the spatial and temporal dynamics of RABV variants in Cameroon. Long genomic sequences of about 4893 nucleotides, encompassing the N, P, M and G genes as well as part of the G-L intergenic region (Ψ), were determined from 56 RABV strains recovered from dog populations in Cameroon from 2010 to 2021. Temporal and spatial dynamics of RABV circulation in Cameroon were investigated by Bayesian analyses with the BEAST 1.10.4 package from extended RABV genomic sequences data combined with their collection dates and the geographical coordinates of their sampling areas. This revealed a genetic evolution rate of 3.14 × 10^-4 substitutions/site/year among Africa-1a and Africa-2 clades of RABV from Cameroon. The most recent common ancestor (MRCA) of the studied strains of the Africa-1a lineage was estimated to have emerged between 1880 and 1906 (95 % HPD; mean 1894), while that of the strains of the Africa-2 clade had a slightly later estimated origin between 1907 and 1928 (95 % HPD, mean 1918). Overall, phylogeographic analyses suggested RABV spread in Cameroon between sub-national regions. Our data provides substantial support to previous findings from similar epidemiological settings, indicating human mediated movements of infected dogs between distant cities may be a key factor in the maintenance of the enzootic cycle of rabies among dogs in Cameroon.