BOVINE BABESIOSIS AND ITS VECTORS AT KOBO AND GIRANA VALLEYS IN AMHARA NATIONAL REGIONAL STATE OF ETHIOPIA.

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2007-06

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A study on bovine babesiosis and its vector was conducted at Kobo and Girana valleys of North Wollo Zone in Amhara National Regional state, Northern Ethiopia. The objective of the study was to determine the prevalence and identify at species level of bovine babesiosis and the vector and indicate the associating risk factor for Boophilus decoloratus tick through longitudinal study. A total of 370 cattle from both valleys were used for a cross sectional study while 60 cattle were also involved in longitudinal study during four consecutive seasons. The longitudinal study was conducted on October, December, January and March that represents late rain, early dry, late dry and early rain seasons respectively. The prevalence of Babesia bigemina in a cross sectional study of age groups <2, 2-4 and >4) was (20.3%, 24.3%, and 16.1%), respectively. The prevalence of B. bigemina among the three age groups was not statistically (p>0.05) significant. Sex (male and female) basis of Babesia bigemina infection rate were (12.7% and 7.6%) respectively and high infection rate (26.5%) were observed in animals with poor body condition than animals with good body condition (15.19%). The prevalence of sex and body condition wise was found statistically (p<0.05) significant. Animals that are found at Kobo valley (22.7%) and Girana valley (17.8%) were surveyed on disease prevalence during a cross sectional study. The prevalence of Babesia bigemina in the valleys was not statistically (p>0.05) significant. The infestation rate of Boophilus decoloratus in age groups (<2, 3-4 and >4) were 73.2%, 82.1% and 91.9%), respectively. And sex (male and female) wise infestation rate were (86.6% and 78.3%), respectively. Age and sex wise prevalence was found statistically (p<0.001 and p<0.05) significant, respectively. Older animals, males and animals with poor body condition were found to carry more ticks than others. Out of the whole Boophilus decoloratus collected, the proportion of females adult ticks were higher in number than males once, that is the ratio male to females was (0.41: 1) and Boophilu decoloratus from the whole tick counts was represent (24.4%), rank third next to Amblyomma cohaerence (24.9%) and Amblyomma variegatum (28.22%). Different tick species have their own preference of attachment sites on their host. Though Boophilus decoloratus has its own preference of predilection feeding sites, but in this study except ano- vulva the tick was collected from all over the host body. Mainly back (shoulder), dewlap, head and ear, but also from venter, tail and hoof. The prevalence of Babesia bigemina during longitudinal study in cattle sub populated by age, sex, and body condition were studied, in general the infection rates were lower, except animals with 3-4 age groups (30%) and sex wise viii prevalence of longitudinal study was found higher than a cross sectional. The difference among age and sex wise were not statistically (p>0.05) significant. Body condition basis prevalence of Babesia bigemina result of longitudinal study was found similar with that of a cross sectional study result and the difference was (p<0.05) significant. The infestation rate of Boophilus decoloratus studied in longitudinal study during four consecutive seasons on animals sub populated by age, sex, body condition, valleys and season was generally lower than that of a cross sectional study and the difference statistically was not (p>0.05) significant except seasons which was found (p<0.05) significant. In all variables studied the prevalence of Boophilus decoloratus was found higher generally during rainy seasons than that of dry seasons. The risk of Boophilus decoloratus infestation was found lower in dry seasons as compared to rainy seasons (OR = 1.56, 95% Cl = 1.43 - 2.39) and the likelihood of acquiring infection was (OR = 3.56, 95% Cl =1.56 - 8.14) 3 times higher in rainy seasons than dry seasons. The main cause of high infestation and infection in the valleys were observed as a result of the unrestricted movement of animals from different part of the country that used to pass via the valleys to the Northern part the country, time less bounded usage of acaricide by different non-ethical individuals, inadequate dosage of acaricide and drought. Restriction of animals' movement, quarantine measures, strong and sustainable extension works should be done to create awareness of the livestock keepers.

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Bovine babesiosis, Boophilus decoloratus, Kobo and Girana valleys, North Wollo

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