Assessment and biochemical characterization of acaricide resistance in livestock ticks of Haryana
Abstract
Objectives of the study were three fold: (i) Assessment of acaricide resistance in Rhipicephalus
(Boophilus) microplus and Hyalomma anatolicum against deltamethrin and diazinon , (ii) Esterase profile pattern
in susceptible and resistant ticks and (iii) antioxidant status/activity in ticks as influenced by acaricides exposure.
The ticks were collected from various areas of Hisar and adjoining districts. Sufficient number of engorged
females of H. anatolicum for acaricide resistance studies could only be collected from the Churu district of
Rajasthan, adjoining Hisar. Rhipicephalus. (Boophilus). microplus ticks of Tohana (Hisar) were found resistant to
both the acaricides while the ticks of Agroha (Hisar) were found susceptible using adult immersion test (AIT). The
same results was obtained by using standard method of larval packet test (LPT). The H. anatolicum ticks of Tara
Nagar (Churu) were found susceptible while of Churu city were resistant by using adult immersion test (AIT). The
same results were obtained by larval packet test except that of ticks of Churu city were also found susceptible. A
comparative analysis of the esterase patterns in susceptible and resistant ticks using non-denaturing
polyacrylamide gel electrophoresis revealed six types of esterases (dubbed as EST-1b, EST-2b, EST-3b, EST-4b,
EST-5b and EST-6b) in R.(B).microplus and four types of esterases (EST-1h, EST-2h, EST-3h, EST-4h) in
H.anatolicum using α-Naphthyl acetate substrate. Qualitative expression of EST-4b while quantitative expression
of EST-5b and EST-6b might be responsible for deltamethrin and diazinon resistance in R.(B). microplus while
qualitative expression EST-4h was probably responsible for diazinon resistance in H. anatolicum. The data suggest
that these AChEs may represent an important detoxification strategy developed to overcome the effects of
acaricides. In acaricide exposed ticks increases in superoxide dismutase (SOD) activity as the concentration of
exposure to acaricides increases suggests better combating of the harmful effects of free radical generation. The
decrease in reduced glutathione (GSH) activity as the concentration of exposure to acaricides increases suggests
utilization of glutathione for combating the oxidative stress caused by acaricides.