Experimental transmission of Langat (tick-borne encephalitis virus complex) virus by the soft tick Ornithodoros sonrai (Acari: Argasidae).

Laboratory studies determined that the soft tick Ornithodoros sonrai Sautet & Witkowski is a competent vector of Langat (tick-borne encephalitis virus complex) virus. When ticks fed on suckling mice having a mean viremia of 10(7.2) plaque-forming units per ml, 52% (n = 208) became infected, and 84% (n = 87) of the infected ticks transmitted virus by bite when fed individually on suckling mice > or = 27 d after the infectious blood meal. Overall, 79 of 184 (43%) of ticks exposed to the original viremic mice individually transmitted virus by bite when tested up to 351 d after the infectious blood meal. In addition, ticks transmitted virus both transstadially and transovarially. Some ticks that transmitted virus during their first transmission attempt were retested. These ticks transmitted virus during 81 (99%) of 82 refeeding attempts, including ticks that transmitted virus 512 d after the initial infectious meal. Therefore, Ornithodoros spp. should be considered as potential vectors of Langat and other tick-borne encephalitis viruses.