A trial at using the systemic action of ivermectin for suppressing the vector capacity of ticks (Ixodidae) infected with the tick-borne encephalitis virus
Alekseev, A.N.; Chunikhin, S.P.; Stefutkina, L.F.
Meditsinskaia Parazitologiia i Parazitarnye Bolezni 1992(5-6): 38-44
1992
ISSN/ISBN: 0025-8326 PMID: 1299761 Document Number: 398978
Adult Dermacentor marginatus hatched from nymphs infected with TBE virus and poisoned with ivermectin retain their vector abilities. Even small individuals with a 1.5-2 times lesser mass as against the reference mass contain the virus in the body in the same titers and the virions in salivary gland alveoli. Administration of an oil solution of ivermectin into the stomach of white mice, nymph feeders, in a dose surpassing threefold the dose recommended for intramuscular injection of this agent completely suppressed shedding of intact nymphs but did not suppress it in those infected. The nymph mass, size and mass of adult ticks hatched from them dropped under the effect of ivermectin dosage build-up in both intact and infected ticks, but these processes were slower in ticks infected with TBE virus. The authors suggest that the ticks infected with TBE virus are much more resistant to the process of gamma-aminobutyric acid depression, the mechanism of ivermectin action. They emphasize the necessity of bearing in mind the possible differences in the reactions to systemic poisons of intact and infected ticks when organizing vector control measures.