Acaricide resistance status of Rhipicephalus (Boophilus) microplus and Hyalomma anatolicum ticks against deltamethrin and diazinon was assessed in Hisar (Haryana) and its adjoining district Churu (Rajasthan) using adult immersion test (AIT) and larval packet test (LPT). The mortality slope, LC50, LC95, 95 % confidence limit and resistance factor of field ticks were determined. Results showed that R. (B.) microplus ticks collected from Tohana (Hisar) were found resistant to both the acaricides while the ticks of Agroha (Hisar) were found to be susceptible using AIT. Similar results were observed by using standard method of LPT. Again, H. anatolicum tick isolates of Tara Nagar (Churu) were found susceptible whereas Churu tick isolates were found to be resistant using AIT for both the acaricides. LPT indicated susceptible status of H. anatolicum ticks collected from Churu as well as Tara Nagar for both the acaricides. The study warrants the need for strategic use of available acaricides to overcome the development of acaricide resistance in ticks.

A comparative analysis of esterases in susceptible and resistant ticks revealed six types of esterases (EST-1b, EST-2b, EST-3b, EST-4b, EST-5b and EST-6b) in Rhipicephalus microplus and four types (EST-1h, EST-2h, EST-3h, EST-4h) in Hyalomma anatolicum using α-naphthyl acetate substrate. Inhibition studies with eserine sulfate, p-chloromercuribenzoate, copper sulphate and phenylmethylsulfonyl fluoride revealed a marked variation in band intensity between susceptible and resistant ticks, with the latter being more intense. Qualitative expression of EST-4b along with an extra band of EST-5b and EST-6b were indicative of deltamethrin and diazinon resistance in R. microplus, whereas qualitative expression of EST-4h was probably responsible for diazinon resistance in H. anatolicum. The data suggest that increased esterase activity may represent a detoxification strategy leading to the development of resistance in these tick populations.

The objective of the study was to reveal physiological link between sex specific engorgement pattern and evading mechanism of ticks against oxidative stress as well as acaricides. Quantitative determination of nitric oxide radical scavenging, superoxide dismutase activity and reduced glutathione (GSH) concentrations in salivary gland and gut extracts of male and female (Acari: Ixodidae) ticks established significant variation in antioxidant responses between two sexes of the ticks. Higher activity of these antioxidants and GSH depletion in females clearly indicate stronger antioxidant defense in female ticks which is to combat host mediated oxidative assault during feeding for greater engorgement and reproductive stress. The females are also better equipped with the mechanism of acaricide resistance as evidenced by higher expression of esterases than males in unfed whole tick extracts in current study.

The aim of the study was to highlight the sex dependent differences in the electrophoretic protein patterns of male and female Haemonchus contortus worms SDS based polyacrylamide gels of both male and female worms were run side by side for comparison. A total of 33 and 35 polypeptides were detected in polyacrylamide gels stained with coomassie brilliant blue R-250, respectively. Besides many of the fundamental homologies in protein profile, some of the polypeptides specific to either sex were also observed. Most of the characteristic polypeptides were of low molecular weight. These polypeptides needs deeper unrevealing regarding the nature of protein, through well planned zymographic studies, so as to ascertain the true nature and/or type of protein involved in those bands. This will help us in better understanding of parasite immunology and sex influenced differences amongst the worm and the possible variations in their pathogenesis contributed thereof, if any.

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