In-Vitro Acaricide Efficacy Evaluation and Survey of Ixodidae Ticks on Cattle in Borena Pastoral Area, Ethiopia
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Date
2012-06-01
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Addis Ababa University
Abstract
This study was conducted from September 2011 to May 2012 in Borena pastoral area with the
objectives of determining the distribution and relative abundance of Ixodidae ticks on cattle in
relation to short rain and major dry seasons, cattle age and sex. Moreover, the efficacy of
Amitraz 12.5% and Diazinon 60%EC against Rhpulchellus and A.gemma was detennined
using modified Adult Immersion Test; on top of the assessment of pastoralist communities'
perceptions on acaricide usage, delivery and methods of tick control practice. A total of 8,912
adult ticks belonging to genera of Rhipicephalus, Amblyomma, Boophilus and Hyalomma
were collected from 768 indigenous cattle. Rhipicephalus pulchellus and A.gemma constituted
more than 70% of the total collection. Other identified species in order of abundance were
B.decoloralus, A.variegatum, H.m.rufipes, H.truncatum, A.lepidium and A.cohearens. All
species were collected throughout the study period, but showed higher overall mean tick
burden (29.39±14.392) during short rain season than major dry (17 .14 ±7.294). These
variations were statistically significant (t= 14.915,95% CI=10.634-13.866, df= 766 P< 0.05).
The abundance and mean burden of each tick species was high in adult cattle than young and
females than males; which also showed statistical significant variation (P<0.05) between
cattle sex and age groups. Acaricide treatment is the only method for tick control in the area,
in which Amitraz was the most widely used, followed by Diazinon. Manual spraying and
hand dressing of each acaricide relaying on frequent, over or under concentration, inadequate
application and a long time use of one acaricide type was the common practice of application.
The result of in-vitro trials revealed that, Amitraz 12.5% has significantly higher (P<0.05)
overall mean percent oviposition control (%C= 95.47%) of A. gemma and Rh.pulchellus than
Diazinon 60% EC (%C= 80.9%). But, both acaricides are relatively less efficient against Rh.
pulchellus oviposition, %C = 90.94% for Amitraz and %C = 71.41 % for Diazinon. The results
of this study suggested that the two seasons, cattle age and sex were found to be determinant
for dynamics of tick population during the study period. Furthermore, Amitraz and Diazinon
are the two mostly used acaricides in the area and under in-vitro condition, Amitraz at field
recommended concentration provides efficient Rh.pulchellus and A.gemma oviposition
inhibition than Diazinon 60%EC. Therefore, strategic control using such seasonal dynamics
of ticks, aimed at primarily reducing Rh.pulchellus and A.gemma burden on female and adult
cattle, with the objectives of allowing maintenance of endemic stability are recommended.
Besides, in vivo trial to assess the residual effect of these acaricides was suggested
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Keywords
Acaricide, Borena pastoral area, Cattle, Efficacy, In-vitro evaluation, Prevalence, Tick