In vitro membrane feeding of the lone star tick (Amblyomma americanum) and its use in evaluation of acaricidal compounds

Authors: Li, Andrew; MENG, HAO - Hebei Academy Of Agriculture; PALMA, KATHLEEN - Piedmont Pharmaceuticals Llc

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/21/2015
Publication Date: 7/11/2015
Citation: Li, A.Y., Meng, H., Palma, K. 2015. In vitro membrane feeding of the lone star tick (Amblyomma americanum) and its use in evaluation of acaricidal compounds. Proceedings of Annual AAVP-LIWC-ISEP Joint Conference. P.103.

Interpretive Summary: The lone star tick, Amblyomma americanum, is one of important Ixodid tick species that are known ectoparasites and disease vectors affecting animal and human health in the United States. New pesticides or repellents with novel mode of action would help control resistant ticks and protect humans from tick bite. Evaluation of acaricides, repellents or other behavior-modifying compounds against ticks often requires laboratory testing on animals. An in vitro assay that allows testing of new pharmaceutical drugs / acaricides without using live animals would offer advantages in terms of animal care and costs associated with animal use. In this study, a silicone-based tick membrane feeding system was successfully developed to feed adult lone star ticks under laboratory conditions. An attachment rate of 61.7% and 72.5% for males and females, respectively, was achieved. The attached females were fed successfully to repletion. However, comparing to ticks fed on animal (cattle), membrane-fed females took a longer time to replete and were smaller in final body weight. The in vitro tick feeding system was utilized to assess toxicity of Resultix, a commercial product of Piedmont Pharmaceuticals, LLC. Resultix, applied topically to female ticks attached to the membrane, at a dose as low as 0.5 µl/tick, caused >83% tick mortality at 24 h post treatment. Application of higher doses (8, 16 µl/tick) caused 90% and 100% mortality, respectively, at 6 h post-treatment. Subsequent physiological experiments demonstrated that Resultix blocked tick respiration and abolished tick feeding activity immediately after topical application.

Technical Abstract: The lone star tick, Amblyomma americanum, is one of important Ixodid tick species that are known ectoparasites and disease vectors affecting animal and human health in the United States. New pesticides or repellents with novel mode of action would help control resistant ticks and protect humans from tick bite. Evaluation of acaricides, repellents or other behavior-modifying compounds against ticks often requires laboratory testing on animals. An in vitro assay that allows testing of new pharmaceutical drugs / acaricides without using live animals would offer advantages in terms of animal care and costs associated with animal use. In this study, a silicone-based tick membrane feeding system was successfully developed to feed adult lone star ticks under laboratory conditions. An attachment rate of 61.7% and 72.5% for males and females, respectively, was achieved. The attached females were fed successfully to repletion. However, comparing to ticks fed on animal (cattle), membrane-fed females took a longer time to replete and were smaller in final body weight. The in vitro tick feeding system was utilized to assess toxicity of Resultix, a commercial product of Piedmont Pharmaceuticals, LLC. Resultix, applied topically to female ticks attached to the membrane, at a dose as low as 0.5 µl/tick, caused >83% tick mortality at 24 h post treatment. Application of higher doses (8, 16 µl/tick) caused 90% and 100% mortality, respectively, at 6 h post-treatment. Subsequent physiological experiments demonstrated that Resultix blocked tick respiration and abolished tick feeding activity immediately after topical application.