Occurrence of Tick Species in Cattle and their Susceptibility Status against Frequently used Acaricides in Morogoro and Pwani Regions

Ticks are important vectors of various tick-borne pathogens causing animal diseases.This study aimed to assess prevalent tick species and the resistance status of the acaricides frequently used to control ticks and tick-borne diseases (TBDs).A cross-sectional study design and purposive sampling method were employed, whereby 952 ticks were collected and stored in plastic bottles containing 70% ethanol, while engorged ticks were placed in perforated plastic containers.Ticks were identified using morphological features.An experimental study design using the larval packet test method was adopted to evaluate the effectiveness of the selected acaricides, whereby a discriminatory dose for each acaricide was prepared by doubling the recommended dose and control using diluents composed of olive oil and acetone at a 1:2 ratio.Out of the 952 tick specimens collected, Rhipicephalus microplus was the predominant species, accounting for 552 ticks (57.9%).This was followed by Amblyomma variegatum with 247 (25.9%),R. decoloratus 65 (6.8%),Hyalomma rufipes 41 (4.3%), R. evertsi 37 (3.8%), and R. appendiculatus 10 (1.1%).On the other hand, susceptibility status was low for the acaricides cypermethrin (15g/L) and α-cypermethrin (100g/L), with mortality rates of 84.60% and 85.70%, respectively.In contrast, the acaricides amitraz (125g/L), amitraz (12.5%), chlorpyriphos (500g/L) + cypermethrin (50g/L), and Chlorfenvinphos (300g/L) showed no resistance, with mortality rates of 97.80%, 97.90%, 99.80%, and 99.90%, respectively.The study revealed that almost all tick species were susceptible to amidines (amitraz) and organophosphates (OPs) (chlorpyriphos and chlorfenvinphos).At the same time, synthetic pyrethroids (SP) (cyclomethrin and α-cypermethrin) showed signs of developing resistance.Therefore, regular monitoring of acaricide resistance is crucial for effective control of ticks and tick-borne diseases.