Experimental Transmission of Karshi and Langat (Tick-Borne Encephalitis Virus Complex) Viruses by Ornithodoros Ticks (Acari: Argasidae).

摘要

Selected species of mosquitoes and Ornithodoros ticks were evaluated for their potential to transmit Karshi and Langat (tick-borne encephalitis virus complex) viruses in the laboratory. Although there was no evidence of replication of Karshi virus in any of the mosquito species tested: Aedes albopictus (Skuse), Ochlerotatus taeniorhynchus (Wiedemann), or Culex pipiens (L.), Karshi virus replicated in and was transmitted by all three species of Ornithodoros ticks tested (Ornithodoros parkeri Cooley, Ornithodoros sonrai Sautet AND Witkowski, and Ornithodoros tartakovskyi Olenev). When inoculated with Karshi virus, 90% of Ornithodoros ticks (44/49) transmitted this virus by bite to suckling mice, and transmission continued to occur for at least 1 yr, the longest extrinsic incubation tested. After feeding on a suckling mouse with a viremia of (caret)105 suckling mouse subcutaneous lethal dose50 units of Karshi virus/ml of blood, all three species of Ornithodoros tested became infected with and transmitted Karshi virus both transstadially and horizontally by bite to suckling mice. In addition, female O. tartakovskyi transmitted Karshi virus vertically to their progeny. In a continuation of a previous study, O. sonrai, orally exposed to Langat virus, were able to transmit this virus after more than 3 years, the longest interval tested. Therefore, Ornithodoros spp. should be considered as potential vectors and as possible long-term maintenance hosts for Karshi virus and other members of the tick-borne encephalitis virus complex.