Seasonal dynamics of ticks (Amblyomma cohaerens and Boophilus decoloratus) and development of a management plan for tick and tick borne diseases control on cattle in the Jimma zone, southwestern Ethiopia

Abstract

In Jimma zone southwestern Ethiopia where the mainstay of the people is coffee and livestock production. A study was conducted on college of agriculture dairy farm and cattle"s of the surrounding district farmers to establish spectrum, burden and seasonal dynamics of ticks on indigenous and exotic cattle, in view of the development of management plan for tick and tick borne disease control. Two different studies have been horizontally conducted population dynamics study throughout the zone and seasonal dynamics study in five localities around Jimma town.In population dynamics study a total of 8642 ticks from 963 cattle collected and eight different tick species with the abundance of (A. cohaerens 62%, B. decoloratus 33%, A. variegatum 3.8%, R.. evertsi evertsi 0.9%, R. praetextatus 0.19%, R. bergeoni 0.06%, R. lunulatus 0.035% and H. aciculifer0.012%) were identified, the two species Amblyomma cohaerens and Boophilus decoloratus was the most abundant ticks in all the seasons.In the seasonal dynamics study fifty cattle from five localities were selected and monthly tick collection performed for two consecutive years (from September 1998 to August 2000) repeatedly. The study result indicates that ticks were present on the animals during every month of the year but there was a reduction in the number of ticks per animal during the dry season. Rainfall was the climatic factor that most affected the seasonal variation in tick infestation. The fluctuations in infestation levels showed the same pattern during both years of the study, although the peaks were different intensities. When the cattle were grouped according to the exotic blood level the cattle with a preponderance of exotic blood presented infestation that were significantly greater than on those with predominance of indigenous Zebu genes.The growth and multiplication of all instars of Amblyomma cohaerens and Boophilus decoloratus were correlated with mean air temperature. Both Amblyomma cohaerens and Boophilus decoloratus had two peaks of activity, in September and October (moderate) and in May, June and July (maximum). No significant increase in tick population was observed during the short rains. There was, however, a greater buildup coincidence with the main rainy season. There was a direct relationship between population and minimum temperatures, whereas maximum temperature seemed to have no such relationship.It is apparent that ticks and tick-borne diseases in south-west Ethiopia are in equilibrium with the predominant local cattle present in the region in a situation know as enzootic stability. Therefore, with these situation eradication of ticks in countries like Ethiopia is generally not feasible and unrealistic. Intensive dipping or spraying programs have been largely unsuccessful in eradicating ticks. Integrated tick control strategies should be advocated, based on host resistant to ticks and the diseases they transmit strategic tick control taking in to account the seasonal dynamics of tick infestation, the availability of medicines and vaccines against ticks borne diseases and cost/benefit analysis of the strategies.In Jimma zone because of the climatic condition that favors their development ticks gives a continuous and substantial challenge to cattle especially between April and October and become difficult to control. In general, to make cattle less attractive to ticks or to develop breeds that are able to defend ticks has less importance; the best solution would be the combination of pasture management, animal management and acaricide use strategy. As part of animal management, an appropriate strategies such as minimal control in period of low challenge November to March and strategic control for high seasonal challenges from April to October can be considered.