Investigation of tick infestations and acaricide susceptibility of ticks among communally grazed cattle in Atiak sub-count, Amuru district

Abstract

Uganda is currently faced with widespread tick resistance to commercially available acaricides. Acaricide treatment is the major if not the only measure of tick control in most Ugandan cattle raising communities. This study aimed to investigate tick infestations, species of ticks and their susceptibility to selected commercially available acaricides on Ugandan market using modified Adult Immersion Test (AIT).. Regional half body tick counts of cattle in the study area generally revealed high infestation with average significant difference tick counts between the different herds as seen in the results’ table 5 & 6. Two tick species of economic importance were identified and they included; A. variegatum and R. appendiculatus. The result of AIT on engorged female ticks demonstrated that Organophosphate (1000g/L), Synthetic Pyrethroid (50g/L) and Co-formulation (50%w/v) all produced 100% oviposition inhibition effect on A. variegatum with mortalities 88.3%, 66.7% and 41.7% respectively. A. variegatum however, did not show susceptibility to amitraz (12.5% w/v) since it proceeded with oviposition and only 16.7% mortality which could also be attributed to other factors such as stress of the experiment was observed. On the other hand, the same concentration of Co-formulation and organophosphate as above demonstrated 100% oviposition inhibition effect on R. appendiculatus with tick mortality of 83.3% and 50% respectively. Synthetic Pyrethroid and amitraz proved resistant to R. appendiculatus where 33.3% and 16.7% respectively proceeded to lay eggs and only 16.7% mortality was registered in each of the two acaricide molecules. Therefore, more laboratory tests using other methodologies such larval Packet Test (LPT) to compare results and be more accurate is suggested.