SPECIES DIVERSITY AND SEASONAL PATTERN OF TICKS AND TICK-BORNE PATHOGENS OF CATTLE IN ADA‟A AND BOSET DISTRICTS, CENTRAL OROMIA, ETHIOPIA
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Date
2017-06
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Abstract
Ticks and tick-borne pathogens are the major health constraints of cattle productivity and contribute to significant economic losses in Ethiopia. A cross-sectional study was conducted from August 2016 through May 2017 to determine the species diversity and seasonal pattern of ticks on cattle during the rainy, dry and short rainy seasons and occurrence of tick-borne pathogens in the highland PAs of Ada‟a and Boset districts, central Oromia, Ethiopia. Ticks were identified to species level by using morphological identification keys under a stereomicroscope. In addition, molecular tools were employed to assess the presence of tick-borne pathogens in blood samples collected from cattle. During the study period, a total of 720 cattle were examined for presence of ticks. The study revealed that 659 (91.5%) of cattle were infested by one or more ticks during the study period. A total of 7430 (5220 males and 2210 females) adults and 794 immatures (46 larvae and 748 nymphs) stages of ixodid ticks that belong to a total of eleven species were collected from cattle during the study period. During the rainy period nine species of ticks belonging to three genera (Amblyomma, Rhipicephalus and Hyalomma) and subgenus Rhipicephalus (Boophilus) were identified, whereas ten and nine species of ixodid ticks were recorded during the dry season and short rainy season, respectively. In Ada‟a district, a total of 3612 ticks were collected in various seasons. From this 907, 987 and 1718 adults and immature ticks were collected and identified in rainy, dry and short rainy seasons, respectively. Nine adult tick species and immature stages of genera (Amblyomma and Rhipicephalus) and subgenus Rhipicephalus (Boophilus) were identified. In Boset district, out of 4612 adults and immature ticks collected, 1235, 621 and 2756 were collected during the rainy, dry and short rainy seasons, respectively. Nine adult tick species and immature stages of genera (Amblyomma and Rhipicephalus) were identified. In the highland (Ada‟a), Amblyomma variegatum, Rhipicephalus (Boophilus) decoloratus, Hyalomma rufipes, Hyalomma truncatum and Rhipicephalus evertsi were the five most commonly encountered tick species on cattle. In the lowland (Boset) district Rhipicephalus pulchellus, Amblyomma gemma, Hyalomma rufipes and Hyalomma truncatum are widely distributed tick species. Amblyomma variegatum (59.6%) and Rhipicephalus pulchellus (77.8%) were the most abundant tick species in Ada‟a (highland) and Boset (lowland) agroecology, respectively.Furthermore, a total of 240 blood samples (120 in Ada‟a and 120 in Boset) were examined by real time PCR to detect the DNA of Babesia bigemina, Ehrilichia ruminantium, Anaplasma centrale, Anaplasma marginale and Trypanosoma theileri in the blood of cattle. Result of the study showed that a total of 182 (75.8%) blood samples were positive for at least one of the aforementioned tick-borne pathogens. Moleular result revealed that Anaplasma marginale (63.4%) was the most prevalent tick-borne pathogens followed by Babesia bigemina (20%) and Ehrilichia ruminantium (10.5%). Anaplasma centrale (4.2%) and Trypanosoma theileri (1.7%) were the least in Boset and Ada‟a districts, respectively. In conclusion, findings of this study suggest that ticks and tick-borne pathogens were the most important problems of cattle of the study areas. Therefore, the increasing threat of ticks and tick-borne pathogens of cattle warrants urgent strategic application of acaricides and creation of awareness among livestock owners to prevent and control tick infestation and tick-borne pathogens of cattle.
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MSc Thesis
Keywords
Seasonal pattern, Tick-borne pathogens