Pharmacokinetics of fluralaner as a systemic drug to control infestations of the common bed bug, Cimex lectularius, in poultry facilities

Abstract

Background: Bed bug infestations are re-emerging in the poultry industry throughout the USA. Although the impacts of bed bugs on birds' health and welfare are poorly understood, adverse outcomes are expected, including stress, anemia, infections and lower production rates. Worker welfare is also an important consideration in commercial poultry farms. A limited number of insecticides are available for use in the complex spatial environment of commercial farms. Systemic drugs have the potential to overcome the limitations of existing pest management tactics. A recent study showed that fluralaner administered to chickens caused high levels of mortality in bed bugs.

Methods: To further understand the efficacy of this approach, we evaluated the pharmacokinetics of an oral solid formulation of fluralaner in 11 chickens and quantified its plasma concentration in chickens using UPLC/MS. We administered fluralaner to chickens with two doses of Bravecto^® (each 0.5 mg/kg body mass) via gavage 1 week apart and evaluated its efficacy on bed bugs that fed on medicated chickens for up to 28 days post-treatment.

Results: Bed bugs that fed on fluralaner-treated chickens experienced > 50% mortality within 30 min of the administration of Bravecto and 100% mortality 2 days post-treatment. Mortality slowly declined to 66.6% by day 28. Fluralaner was quantifiable in the hens' plasma for at least 28 days post-treatment. The treatment resulted in maximal plasma concentrations (C_max) of 106.4 ng/ml around day 9.0 (T_max), substantially higher than the LC₉₀, the concentration needed to kill 90% of the bed bugs.

Conclusions: Fluralaner appears to be a promising candidate for bed bug control in poultry farms, with a treatment effect lasting at least 28 days.

Keywords: Bed bugs; Cimex; Ectoparasites; Fluralaner; Pharmacokinetics; Poultry.