TICK FAUNA OF GOAT WITH A REFERENCE TO THEIR VECTOR STATUS AND ACARICIDE RESISTANCE
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Date
2016-06
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College of Veterinary Science Assam Agricultural University Khanapara, Guwahati-781022
Abstract
The present study on tick fauna of goat with a reference to their vector status and acaricide resistance was carried out with an aim to obtain current information on ticks, acaricidal resistance status in ticks and prevalence of haemoparasitic infection in goats reared under different management system from March 2015 to February 2016 in and around Guwahati. Observation on the prevalence of ticks revealed Haemaphysalis bispinosa as the only tick found infesting goat of the study area with 53.98% prevalence out of 528 animals examined and availability throughout the year . Tick prevalence was recorded highest in monsoon (71.67%) and lowest in winter (27.42%).Sex-wise ,female were found mostly infested (61.59%) then male (8.00%) . On the basis of distribution pattern on the body sites of goat ears were found mostly infested (89.82%) and least in tail (12.28%).
Acaricide resistance test by in vitro methods AITDD (Adult Immersion Test with Discriminating Doses) was performed against synthetic pyrethroid Deltamethrin which have been used continuously in GRS (Goat Researh Station Burnihat ) for the past 20 years and also against newly used synthetic pyrethroid Cypermethrin in Haemaphysalis bispinosa tick collected from GRS Burnihat. Ticks were also collected from Tetelia goat farm (unorganized farm) to detect acaricide resistance. Results revealed 80% resistance against Deltamethrin and 30% resistance against Cypermethrin in GRS Burnihat and 20% and 0% against Deltamethrin and Cypermethrin in Tetelia farm. Filter paper impregnation method was performed to determine the larvicidal effficacy of Deltamethrin and Cypermethrin at different (0.5,0.1 and 0.2 % concentration) showed 100% mortality of H.bispinosa larvae at 0.2% concentration of Deltamethrin in both GRS and Tetelia farm and 100 % mortality at 0.2% concentration of Cypermethrin at GRS Burnihat but 100% mortality at 0.1and 0.2% concentration of Cypermethrin in Tetelia farm as it was not used there as acaricide, indicating more larvicidal efficacy in Tetelia farm.
Prevalence of Theileria sp. was determined by microscopic examination of Giemsa stained blood smear and confirmation through PCR by using genus specific primers .Further sequencing confirms the presence of Theileria luwenshuni as the first caprine Theileria sp. prevalent in the goats of Assam.
An attempt was made to determine the T .luwenshuni infection in the salivary gland of the H .bispinosa by PCR assay but was found negative as level of parasitaemia exists in the blood sample less than 0.0001%. So it was not possible to trace the infection in the salivary gland of the tick.
A total of 16 clinical theileriasis cases caused by T.luwenshuni were recorded during the period of study irrespective of different breeds of goats (9 cross bred , 7Assam local). All the clinical cases were recorded in unorganized farms and smallholders of goats under semi intensive system of management. Based on the status of the animal clinical theileriasis was recorded in 3 lactating goats and one male buck that was having recent history of castration .Animals positive for clinical theileriasis showed symptoms of anorexia ,depression, fever ,pale mucous membrane and weakness. Haematological changes revealed anaemia in goats.
In the present study 39.87% goats irrespective of different breeds were recorded with sub clinical theileriosis without showing any clinical symptoms. Haematological findings revealed moderate anaemia in subclincal carrier goat in comparsion to healthy animals. This suggests that Theileria luwenshuni is first time emerging as a new Theileria species responsible for both clinical theileriasis and subclinical theileriosis in the goats of Assam.
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