Biological effects of ivermectin on the fowl tick Argas (Persicargas) persicus (Oken) (Ixodoidea: Argasidae)

The present study is carried out to assess the effect induced by different single subcutaneous injections of ivermectin (IVM) (100, 200, 400, 800 or 1600 μg/kg pigeon weight) injected 2 or 7 days before tick feeding on some biological parameters such as mobility and viability, sexual activity, ingested blood, amount of coxal fluid, blood digestion and fertility in the tick Argas (P.) persicus to define the effective dose. This effective dose was used in similar assessment conducted 2 or 3 weeks post injection in order to confirm the degradation of ivermectin concentration in the host blood and to determine the number of required doses for complete control . From this study we conclude: 1) IVM induces complete immobilization of both males and females when they are fed on hosts injected by doses over 100 μg/kg. 2) The use of two doses of 400 μg/kg with a week interval completely controls the tick population. 3) Sexual response was completely negative at doses over 200 μg/kg. 4) The amount of coxal fluid emitted by both sexes decreased markedly when fed after host injection with all doses, whereas the amount of ingested blood remained generally not highly affected. 5) The number of ovipositing females, number of eggs deposited and their hatching percent decreased markedly with the increase of dose used. Blood digestion was not noticed in males at doses >200 ug/kg and in females at doses >100ug/kg .