Epidemiology and Genetic Characterization of Rabies Viruses in Middle of China

Background To analyze the epidemiological characteristics of human rabies in Henan Province and perform a genetic characterization of the rabies virus (RABV). Methods The rabies case data were retrieved from the National Infectious Disease Reporting Information Management System and individual case investigation forms. Saliva, cerebrospinal fluid and serum samples from rabies patients were collected and tested via real-time PCR. Positive samples were subjected to sequencing of the RABV N gene, and the sequences were compared with reference sequences in GenBank for homology and phylogenetic analysis. Results Among the five rabies cases (cases 1–5) examined, two were associated with bites from domestic dogs and were classified as level III exposure. The exposure source and level for the remaining three cases were unknown. None of the patients had received vaccination or passive immunization. Real-time PCR tests revealed that saliva samples had the highest positivity rate (87.5%), whereas CSF and serum samples tested negative for viral RNA. The N gene sequences from the four rabies cases (cases 1–4) were identified as belonging to the China I strain, a dominant rabies virus strain in China, with nucleotide homology ranging from 99.26%-99.85% and amino acid homology of 100%. The major functional and antigenic sites of the encoded protein are highly conserved. Conclusion Rabies continue to circulate in Henan Province. However, the evolutionary diversity and genetic stability of circulating strains of the rabies virus are limited.