Study on the status of bovine tick infestation, in Guba-koricha District in West Hararghe zone, east - Ethiopia

A cross-sectional study was conducted from November 2010 to April 2011 to determining the prevalence of tick infestation, to identify the common tick species in cattle andto assess the major risk factors associated with the occurrence of tick species in Gubakorichadistrict WestHararghe zone of Oromia regional state, southeast Ethiopia.Ticks were collected by searching and half body of animals using forceps on different regions of the animals’ body. A total sample of 384 cattle, 234 were found to be infested by one or more tick species an overall prevalence of 60.9%. The most predominant isolated ticks species in this study were R.pullchelus with isolation rate of 49.4% followed A. Varigatum with isolation rate of 30.3%, H. marginatumrufipes, the third predominant with isolation rate 11.8%. However, A. gemma, H. trucatum and R. Evertsi-evertsi was the least isolate which accounts for 3.6%, 2.4% and 2.35% respectively.Age, sex and body conditions scoring were found to be important risk factors associated with tick infestation. The prevalence of tickinfestation between age and sex was statistically significant (X 2 =32.3075, CI=0.1323358-0265075, P=0.000 andX 2 =5.117, CI=0.1953184-0.0061713, P=0.037) respectively. However, breed and body condition were not statistically significant (P>0.05). Hereof, Ticks are obligate, blood feeding ecto-parasites that cause severe damage to the hides and skins of domestic cattle due to this reduce the foreign exchange of the country; and also transmit tick borne diseases. Therefore, effective tick control programs should be formulated and implemented at national or regional level.


Introduction
Ethiopia, located in the horn of Africa, it has an extremely diverse topography; a wide range of climatic features and multitudes of agro-ecological zonation which makes the country suitable for different agricultural productionfor 85-90 % of the people of Ethiopia is agriculture (CSA, 2004).
Ethiopia is endowed with the largest livestock population in Africa. Therefore, livestock play a vital role in the farming system of the country mainly used for draught power, milk and meat production and source of manure. Unfortunately, the contribution of this huge natural resource to human nutrition and export earnings is dis-proportionally low. The Ethiopian livestock contributes only 15 % to the GDP. Total herd meat off-take is estimated at around 7 % annually, which is perhaps one-third lower than the average for tropical Africa. Cattle are a prime resource for the people and government of Ethiopia. The country has the largest cattle population in Africa, estimated at 35 million head (CSA, 2002).
Ticks are obligate, blood feeding ecto-parasites of vertebrates, particularly mammals and birds. It has been estimated that about 80% of the world population of cattle are infested with ticks. The lifecycle of ticks (both Ixodids and Argasids) undergo four stages in their development; eggs, 6legged larva, 8-legged nymph and adult (Minjauw and McLeod, 2003).Based onthe number of hosts required to complete their development during their life cycle they can be classifiedas onehost, two-host and three-host ticks (Walker,et al,. 2003).Although, only relatively few of more than 889 species of tick in the world are important to man and his domestic animals, these few species must be controlled if livestock production is to meet world needs for animal protein (Drummond, 2007). Over 79 different species are found in eastern Africa but many of these appear to be of little or no economic importance (Cumming, 1999).But out of over 79 ticks species in Ethiopia, there are 47 species of ticks found on livestock and most of them have importance as vector and disease causing agents and also have damaging effect on skin and hide production (Kassa, 2005)and also they down grade hide and skins quality and reduce milk and wool production, reduce productivity and increase susceptibility to the other diseases (De Castro, 1997).
Ticks also have adverse effect on livestock in severalways and parasitize a wide range of 3 vertebrate hosts andtransmit a wide variety of pathogenic agents than anyother group of arthropods (Oliver, 1989).
They transmit protozoa,bacterial, rickettsia and viral diseases in domestic animals. They also cause nonspecific symptom like anemia, dermatosis, toxicosis and paralysis .
In Ethiopia ticks are common in all agro ecological zones of the country (Pegram, et al., 1981).
Therefore, relevant data on the distribution of ticks is essential for the development of effective tick and tick borne disease control strategies. Studying ticks on livestock under their natural conditions without any control measure is also useful for understanding the host parasite relationship and variation of tick population in different agro-ecological zone.Different tick species are widely distributed in Ethiopia and a number of researchers reported the distribution and abundance of tick species in different parts of the country. Amblyomma tick is one of the most abundant tick genera and has been reported in many parts of the country, such as Nekemte (Belete, 1987), Hararghe (Guliat, 1987), AsellaBehailuAssefa (2004), Awassa (Mehari, 2004), MizanTeferi (Seid, 2004) and Jimma (Yitbarek,2004), with highest prevalence rate as well as Rhipicephalus is also predominant genera and has been reported with highest prevalence in GamoGofa (Jewaro,1986), Bale (Dejenu, 1988) and Southern Sidamo (Sebsibe,1988).Boophilusand Hyalomma ticks also have a significant role.
The populations of tick are influenced by climatic changes, which affect the rate of tick population on the ground, host resistance and natural enemies Solomon Gebre et al., (2001).
Amblyommacohaerence is prevalent andabundant in western humid highland areas of Ethiopia.
Boophilusdecolaratusand Rhipicephalusevertsievertsi are widely distributed in most altitudinalranges BekeleHailu (1987).Therefore, this study was designed with the aims of  To determiningthe prevalence of tick infestation of cattle in the study district.
 To identify the common tick species in Gubakoricha district .
 To assess the major risk factors associated with the occurrence of ticks species in the study area.  Muslim; with 86.11% of the population reporting they practiced that belief, while 12.02% of the population said they professed Ethiopian Orthodox Christianity and 1.8% was Catholic.

Study population
According to Gubakoricha district Agricultural Bureau (2009), the live stockspopulation of Gubakorichagenerally, about 219,593 live stocks, out of this 83,168 are cattle and the rest are other species of animals. The study populations were constituted in all breeds but the mostly populated breed in the area was indigenous or local breeds kept under mixed farming system andPeople of 5 the district are directly depending on livestock and agricultural production to boost the quality and quantity of this product.

Study Design
A cross-sectional study was conducted from November 2010 to April 2011to determining the prevalence of tick infestation,to identify the common tick species in cattle and to assess the major risk factors associated with the occurrence of tick's species in Gubakorichadistrict WestHararghe zone of Oromia regional state.

Sampling and Sample Size Determination
For estimation of the prevalence of ticks, since there was no work done in the study area,the cattle to be examined were selected by simple random sampling method, and the sample size was determined by assuming of using the formula described by Thrusfield (2005).The expected prevalence of Ixodidaeticks of cattle in GubakorichaDistrict was assumed as 50%. The parameters used were 95% confidence interval and 5% desired level of precision. By substituting these values in the formula, the sample size taken was n = 384 N= 1.96 2 Pexp (1-Pexp) D 2 2.5. Study Methodology 2.5.1. Sampling procedure and techniques Ticks were successfully collected from cattle after being restrained using strong crushes, by physical handling. Ticks were collected by searching andhalf body of animals using forceps on different regions of the animals' body. Ticks were collected from ears, heads, dewlaps, belly/flunk, udder/scrotum, perineum and legs/tails in the separated sample bottles. The skin of each study cattle was inspected for the presence of ticks. All adults (Both sexes) were collected by using universal bottles; collected ticks were preserved in 70% ethyl alcohol and transported to Hirna regional veterinary laboratory forthe ticks were counted and subsequently identified to genus 6 and species level by using stereomicroscope, according to standard identification keys given by Walker et al. (2003). First ticks were seen grossly and classified to different genera levels and identified into their species level depending up on their morphological structures.
During tick identification in the laboratory the sample were put on Petridis and examined under stereomicroscope.

Methods of Data Management and Statistical Analysis
The data collected during sampling and laboratory findings were entered and stored in MS-excel.
Before subjected to statistical analysis, the data were thoroughly screened for errors and properly coded. An intercooled Stata 9 software package (Stata Corporation, 2005) was used to perform the statistical analysis. Descriptive statistical analysis such as table was used to summarize and present the data collected. Ticks prevalence was calculated as percentage by dividing the number of animals positive to the total sampled animals. Pearson chi-square (χ²) test was employed to assess the existence of association between tick infested cattle's and different potential risk factors considered in the study. For this analysis P-value <0.05 were considered significant whereas Pvalue >0.05 considered non-significant. 7

Prevalence of ticks on cattle in Gubakoricha district
Out of the total sample of 384 cattle, 234 were foundto be infested by one or more tick speciesan overall prevalence of 60.9%. A total 1572 Ixodid ticks were collected among which three genera ofticks were identified. Rhipicephaluswas themost abundant (51.8%) genus and Hyalomma wasconfirmed to be the least prevalent (14.25%) tick genus (Table 1).     Body condition score: were also consideredduring examination, animals were divided into threebody condition scores as shown in the (table 6)

Discussion
The distribution and abundance of tick species infesting domestic ruminants in Ethiopia vary greatly from one area to another area.The study was carried out to determine the prevalence of tick infestation in cattle, to assess the major risk factors in the study areas. From the total of 384 local and cross breed cattle, the overall prevalence recorded was 60.9%. It is disagree from the findings ofNigatu andTeshome, who reported an overall prevalence of(89.4%). However, it is higher than the findings of Belewand Mekonnenwho reported an overall prevalence of33.21%.This difference could be due to the difference in the agro climatic condition of the study areas. Tickactivity was influenced by rainfall, altitude andatmospheric relative humidity (Pegram,et al., 1981). variegatum is the most common andwidely distributed cattle tick in Ethiopia (Morel, 1980, Pegram, et al 1981.
It has a great economic importance, because it is an efficientvector of Cowderiaruminatum and greatest damage toskin and hide, due to its long mouth parts, so it willreduce the value on world market . Also, ulcercaused by this tick species becomes favorable site forsecondary bacterial infection like Dermatophiluscongolensis.
H. marginatumrufipes was identified as the 3 rd abundant ticks species collected in the study area. H. trucatum is the least abundant tick species constituting 2.4% of the total of adult tick collection in the study area.This results was disagree with the results have been reported by Regassaa (2001) in Borena this due to the agro ecological condition which is low land and receive small rainfall but in our study areas altitude factors which govern the distribution of ticks in the study area. In sub shara Africa, H. trucatum is very wide spread and often common. It is abundance may be influenced by the abundance of hare that are preferred hosts of the mature stages (Walker,et al,.2003).
R. evertis is the least abundant tick species constituting 2.35%of the total of adult tick collection in the study area. In contrast to this study this tick species was reported to be prevalent by other authors such as Mesele in Bahirdar (1989), Behailu, 2004 andMorel, (1980) mentioned that the native distribution of R. eversi in Ethiopia seems to be connected with middle highland, dry savannas and steppes in association with zebra and ruminant.
The geographical distribution of survey of tick's conducted in Gonderawraj by Eshatu (1988) found that R. evertsi was the most abounded tick species of the area. This may due to the geographic location, seasonal variation of the area or may be due to variation in microclimate factors (Singhet al., 2000) including higher rainfall associated with high soil moister content which is favorable on the survival of tick vectors.Thistickshows no apparent preference for any particular altitude rainfall or season (Pegram,et al., 1981).
The present study also revealed that ticks select favorable site for their attachments on the body of cattle, Howell et al., (1978) in South Africa who reported that similar favorable site of ticks to attach themselves on the cattle's body.Information on predilection sites of ticks is helpful in spraying individual animals since it gives a clue as to which part of the body requires more attention (Pegram et al., 1981).
The male to female rations ofall ticks species except in the case of A. gemma ticks species the number of female ticks species higher than male ticks species. The male to female rations of R. host up to several months to continue feeding and mating with other females on the host before dropping of SolomonGebre,et al., (2001).
During the study period, the prevalence of tick infestation was assessed between three age group cattle. The adult and old are more sustainable than young due to the fact that the young are not often driven with adult and old age group into grazing and water points. This practice naturally reduces the chance exposer of young cattle to ticks.
During the study period, the prevalence of tick infestation was assessed between sex of animals higher prevalence was recorded in female animals (63.6%) compared to male (57.7%). This variation may be associated with male animals which were kept properly in the house with good management system for beef purpose whereas, female animals grazing on field all day may be exposed to tick infestation. In current study there is significant association of tick infestation between sexes of animal. This foundingdisagrees with Endale, (2006).
The study also revealed that the prevalence of tick infestation was assessed between local and cross breeds was recorded 63.03% and 33.03 % respectively.The fact that more tick burden was recorded in local breed as compare to cross breed animals this due to differences in management systems, lack of supplementary feeding to local cattle breeds, or lack of control measures against tickon local cattle breeds. Furthermore, it can be assumed thatit might be due to lack of interest of farmers about localcattle and taking more care to cross breed.In current study there is no significant association of tick infestation between two breed of animal (X 2 =0.4005, CI=0.1301061-0.2381844, P=0.564).

4.Conclusion and recommendation
Ticks are obligate blood feeding ectoparasites of vertebrates, among ecto-parasite it cause the greatest economic loss in livestock population either by transmitting a wide variety of TBDs or by affecting the health of animals as well as the quality of hide and skins.In this study an overall 16 prevalence of tick infestation 60.9% were obtained by using half body count and stereomicroscope. age, sex, breed and body condition scoring. Whereasage and sex have significant association with infestation of tick.Furthermore, predilection sites are identifies that helps in designing control methods and which parts of the cattle's body to be covered while using ectoparasiticide chemicals.Therefore, to minimize the impact effective tick control program should be formulated and implemented at national and regional level based on the distribution pattern of ticks and factors responsible for their distribution.In light of the above conclusion the following recommendations are forwarded:- Tick should be managed at an economical acceptable level by a combination of techniques and this requires familiarities with the tick species present and an understanding of their epidemiologyfor the continuous understanding of improved controlstrategies.
 Awareness creation for farmers and extension agents to accept the benefits gained from both boostingimmunity to TBD and achieving host resistance to ticks that would result from relaxedtick control regimes.
 Adjust animal husbandry practice based on defense reaction of the animal against tick.
 A strong veterinary service structure has to be established to strengthen tick surveillance network at national level, co-ordinate data collection, implement appropriate control and preventive measures.