Transmission of Kyasanur Forest disease virus by Rhipicephalus haemaphysaloides ticks.

Larvae of Rhipicephalus haemaphysaloides were infected with Kaysanur Forest disease (KFD) virus by feeding on viraemic rodents and reared into next generation larvae. Fed larvae, nymphs, unfed adults, fed adult males, and females after oviposition were found infected, while the larvae were found free from infection. Nymphs and adults transmitted the infection by bite to rodents and rabbits respectively. The virus was also passed through a second rodent-tick cycle. Adult ticks showed a titre of 3.1 to 4.5 dex mouse LD50/0.03 ml, and the virus was also detected 245 days after infection.