STUDIES ON PREVALENCE OF THEILERIA ANNULATA IN TICK VECTORS INFESTING CATTLE OF COASTAL ODISHA
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Date
2018
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Orissa University of Agriculture and Technology, Bhubaneswar
Abstract
The present study entitled “Studies on prevalence of Theileria annulata in tick
vectors infesting cattle of Coastal Odisha” was carried out from March 2016 to February
2017. A total of 3014 cattle from different villages in 16 blocks of four districts of coastal
Odisha (Cuttack, Puri, Jagatsinghpur and Khurda) were screened for presence of tick
infestation. The cattle of either sex, varying age groups (< 1 year and >1 year), different
breeds as well as different health condition were included. Adult semiengorged ticks were
dissected and salivary gland were collected and subjected to DNA extraction. Nested PCR
was carried out by targeting the Tams1 gene of Theileria annulata, utilizing two sets of
primers (N516F, N517R and Ta14136iF, Ta249R) in order to detect the parasite. The PCR
products were then sequenced and blast analysis was carried out.
The overall prevalence of ticks in the coastal districts was found to be 39.48%. The
ticks encountered during the study were; Rhipicephalus (Boophilus) microplus (62%) which
was most abundant followed by Hyalomma anatolicum (31%) and Rhipicephalus sp (7%).
There was higher prevalence in females, upgraded breeds, cattle with poor body condition and
young cattle. There was significant difference between the tick count of different ticks
infesting cattle of the four districts while no significant difference could be found between
different districts. There was also significant difference between the various seasons with
regards to tick count in the four coastal districts. The abundance of Rhipicephalus (Boophilus)
ticks were high during monsoon while Hyalomma ticks were more prevalent during pre
monsoon. The correlation of environmental factors on overall tick infestation revealed a high
correlation (r= 0.820) between the mean monthly tick burden and average monthly rainfall as
well as minimum temperature (r=0.865) with statistical significance (p< 0.01). The molecular
diagnosis of Theileria annulata. revealed an overall prevalence of 14.78% in tick vectors. A
higher presence with significance were recorded for Theileria annulata in female ticks (12.74
%) over their male counterparts (11.48). A total of four Tams1 PCR amplicon were randomly
selected and the obtained sequence results were confirmed as Theileria annulata.
Our study confirmed the presence of causative agent of bovine tropical theilerosis and
the risk of cattle to contract the disease. A positive correlation of rainfall and minimum
temperature with tick as well as disease prevalence suggests control measures to be applied
on the onset of monsoon to control tick and tick borne diseases.
Description
Th-5610
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