Molecular study of rabies virus in slaughtered dogs in Billiri and Kaltungo Local Government Areas of Gombe State, Nigeria

INTRODUCTION: Rabies is one of the most dreadful diseases and a major viral zoonosis which has an almost 100% case fatality rate in infected victims. It is characterized by acute progressive encephalitis, ganglioneuritis and parotid adenitis in mammals. There are many variants (strains) of the virus, each maintained in a particular reservoir host. This study aimed at determining the genotypic characteristics of rabies virus isolates in dogs slaughtered for human consumption based on fragment of the nucleotide (N) gene. METHODS: brain tissues were collected from 50 slaughtered dogs in Billiri and Kaltungo Local Government Area of Gombe State and screened for the presence of rabies virus antigen using direct fluorescent antibody test (DFAT). Viral RNA from DFAT positive brain tissues were subjected to the reverse transcription polymerase chain reaction (RT-PCR) followed by sequencing of the amplicons. Maximum parsimony (MP) method was used to construct phylogenetic trees for sequences obtained with 1000 bootstrap replicas. RESULTS: rabies antigen was detected in 3 (6%) of the 50 dog brain tissues by DFAT. Of these 1/50 (2%) was positive by RT-PCR. The N gene fragment of the positive isolate was found to have between 97% to 99% identity to previously sequenced fragments of N gene of rabies virus from Nigeria and other neighboring African countries (Chad and Niger Republic), suggesting in-country and trans-boundary circulation of the virus within West Africa, the Africa 2 lineage. CONCLUSION: this finding has given additional insight into the molecular characteristics and epidemiological linkage of rabies virus, dynamics for designing of rabies control programs in the country.