Results and Discussion
The Samples Fox1_C_thous_PB_Brazil_2010 and Fox2_C_thous_PB_Brazil_2013 were similar to a cluster containing strains isolated from wild and domestic Brazilian canids, and to the subcluster C. thous (Figure 1B). Therefore, we confirmed the existence of a RABV lineage circulating in the C. thous , that is distinct from previous reports describing RABV in the same host species (Carnieli et al, 2013).
Crab-eating foxes are RABV reservoirs due to factors of high susceptibility of this species to this virus, the virus incubation period, the morbidity period, the clinical syndrome observed and the long period necessary for viral dissemination through the parasympathetic nervous system of the foxes (Hanlon, 2013). Importantly, in the State of Paraiba the RABV is endemic, and infects domestic and wild animals during the whole year, with peaks every four years (Bernardi et al, 2005).
Next, we used the results of the deep-sequencing analysis to search for variants in the viral population. We observed the existence of a C>T mutant in the L gene (nucleotide 10,733), which caused the non-synonymous mutation Ala1775Val. This mutation reached the frequency of 30% of the reads in the region (Figure 1C). Although this variant did not reach the threshold of dominance (50%), it hints the existence of a heterogeneous virus population, and the existence of possible escape mutants
Reports of wild rabies increased recently, and in the present study we report a new lineage of RABV in C. thous in Northeastern Brazil. The contact between foxes and dogs has the potential to generate new RABV variants. Therefore, continued rabies vaccination programs for dogs, and surveillance of rabies in wild animals are essential to prevent cases in humans, and to prevent the emergence of new virus lineages.