Experimental transmission of Crimean-Congo hemorrhagic fever virus by Rhipicephalus evertsi evertsi (Acarina : Ixodidae) tick.

We have conducted experiments to assess he ability of Rhipicephalus evertsi evertsi tick to transmit the Crimean-Congo haemorrhagic fever (CCHF) nad d etermine their reproductive cycle. The Rh. e. evertsi was infected by intra c oe lomic (transparietal and intra-anal) inoculation during the imaginal s tases and by oral feeding on an infected viremic goat during imaginal and n ymphal stases. The infection rate, transovarial and trans-stasial CCHF viru s transmission were monitored for virus reisolation after suckling mice ino culation and the virus identified by ELISA and IFA for antigen detection. After intrac oe lomic inoculation, unfed adults had viral titers ranging fr om 0.67 to 2.9 log DL50/0.02 ml and had transmitted the virus to their vert ebrate hosts by blood feeding. After 8 to 10 days of blood feeding duration , infection rates were respectively 36% and 100% for male and female ticks. In two instances out of seven transovarial transmission was observed and t he virus reisolated from larvae of first generation. However; the virus was not detected after nymphal metamorphosis. After blood feeding on viremic g oats, 71% of the nymphae were infected. After metamorphoses 22% of the male s and 42% of the females had a low virus titer. Rh. e. evertsi appears to have a limited efficacy in transmitting and repli cating the CCHF virus but must be not neglected as a potential vector durin g an epizootic manifestation.