Abstract

Tick infestation is considered to be a major concern as ticks cause widespread distress, act as vectors of disease and affect the economic conditions of livestock-rearing. Although the use of chemicals is still the most effective method of tick control, uncontrolled applications may have accelerated the emergence of tick resistance to several active ingredients available. The present work estimated the efficacy of two commonly used acaricides (amitraz and diazinon) against Rhipicephalus pulchellus and Hyalomma dromedarii collected from Camelus dromedarius by using in vitro and in vivo field trial methods. The in vitro test employed a preliminary immersion technique and the field trial involved a manual application of the acaricides on camels predominantly infested with both tick species under field condition. Three groups of camels (I, II and III) containing six head of animals each with a mean number of >20 tick counts received diazinon, amitraz and distilled water, respectively. The in vitro assay showed no statistically significant tickicidal difference (p>0.05) between these compounds although amitraz proved a relatively better efficacy. For both acaricides, doubled concentration was more effective in tick killing. The field trial evidenced that both drugs caused a significant reduction (p<0.05) in mean tick count when compared to the negative control. However, amitraz showed a significant superiority (p<0.05) as compared to diazinon (85.2%) eliminating almost all ticks from the body of infested camels 72 h post treatment with 99.1% efficacy. Whereas, the maximum antiparasitic efficacy brought about by diazinon was 85.2% after 72 h of application. In conclusion, comparing the efficacy of the two acaricides from these preliminary tests, amitraz is the preferable one. Furthermore, right application and choice of acaricides needs to be pursued in order to avoid any resistance against ticks in camels.

Key words: Amitraz, camel, diazinon, efficacy, Rhipicephalus pulchellus, Hyalomma dromedarii.