Molecular epidemiology of human rabies viruses in Sri Lanka.

Rabies is a lethal zoonotic disease caused by the rabies virus, which is transmitted by rabid animals to humans. Rabies is prevalent in all continents, with over 60% of human deaths occurring in Asia. Sri Lanka is a rabies-endemic country. This study shows that rabies afflicted more older individuals than children in Sri Lanka between 2008 and 2010. This novel finding indicates that older people in Sri Lanka should be more aware of the risk of rabies. Phylogenetic analyses of the rabies N and G genes showed that the Sri Lankan rabies viruses are distinct and probably originated from a single clone. The G-L noncoding region is highly diverse, and is suitable for the analysis of virus evolution within a country. A phylogenetic analysis of this region showed high diversity in the currently circulating Sri Lankan rabies viruses, which can be divided into seven clades. Some clades are unique to a specific geographic region, whereas others occur at multiple locations. This indicates that the movement of dogs, the main rabies-transmitting animal in Sri Lanka, is restricted in some areas but less limited in others. These data may help to formulate a more efficient rabies control program in Sri Lanka.