ydatidosis caused by the larval stage (metacestode) of Echinococcus granulosus is the most widespread parasitic zoonoses (Ibrahim, 2010;Getaw et al., 2010). Dogs are the usual definitive hosts while a large number of mammalian species are intermediate hosts, including domestic ungulates and man. It is a familiar with many different countries (cosmopolitan) zoonotic infection (Azlaf and Dakkak, 2006).

Despite the large efforts that have been put into the research and control of echinococcosis, it still remains a disease of worldwide significance. In some areas of the world, Cystic echinococcosis caused by E. granulosus is a re-emerging disease in places where it was previously at low levels (Urquhart et al., 1996; Kebede et al., 2009a).

Echinococcus granulosus infection is endemic in East and South Africa, Central and South America, South Eastern and Central Europe, Middle East, Russia and China. The highest incidence is reported mainly from sheep and cattle rearing areas (Arene, 1995). The disease is most important in livestock production which is based mainly on extensive grazing system. Several reports from different parts of Ethiopia indicate that Author ? ? ?: Jimma University, College of Agriculture and Veterinary Medicine (JUCAVM), P.O.Box 307. e-mails: [email protected], [email protected], [email protected] hydatid cyst is prevalent in livestock population of the country (Jobre et al., 1996;Kebede et al., 2010).

According to Abebe and Yilma (2011) a prevalence of 72.4%, 37.72%, 33.78% and 13.7% in cattle slaughtered in Asella, Adama, Gonder, and Dire Dawa was documented respectively indicating its importance in the livestock industry. Its distribution is higher in developing countries especially in rural communities where there is close contact between dogs (definitive host) and various domestic animals intermediate hosts (Eckert and Deplazes, 2004). By affecting many animal species, intermediate animal hosts and humans, hydatid cyst causes tremendous economic losses worldwide and specially in those areas where the parasite is endemic (Urquhart et al., 1996).

Knowledge about the prevalence of the diseases together with associated risk factors as part of the epidemiology of the disease is crucial for any attempt of prevention and control of the disease in question. Moreover, determination of the economic significance of the disease is important for decision making, planning, and implementation of local control strategies. The present study were, therefore, conducted in the area with objective of determining the prevalence of Hydatidosis, its associated risk factor in cattle slaughtered at Jimma municipal abattoir and to estimate the economic significance of the disease in cattle.

The study was conducted in Jimma town which is located at about 352km south west of Addis Ababa. The area receives a bimodal rain fall with an average annual rain fall of 1530mm. The long rainy season occur during the months of June to September while the short rainy season occurs during the months of March to May. The climatic condition of the town is "Weynadega" and the town is located at an altitude of 1915masl. The annual maximum and minimum temperature ranges from 24-30C? and 7-14C? respectively. According to the statistical data obtained (CSA, 2009), Jimma district has a livestock population of 2,016,823 cattle, 288,411 goats, 942,908 sheep and 74574 horses, 49,489 donkey, 28,371 mules and 1,139,735 poultry.

The study animals were local breeds of cattle coming from different wereda of the Jimma zone to Jimma municipal abattoir. Only male cattle and sheep were slaughtered, but majority of animals slaughtered in the abattoir were male cattle. The majority of slaughter animals came from seven weredas, this are Agaro, Asandabo, Bilida, Dedo, Jimma, Sarbo and seka. The body condition score was classified into poor, medium and good (fat), (Nicholson and Butter worth, 1986). The age was determined by dentition formula according to the method described by De Lahunta and Habel (1986), and animals categorized into three age groups (< or = 5, 5 -8, and > 8 years).

The study animals were selected from the slaughter line using simple random sampling technique. The required sample size was determined based on prevalence of 61% (Koskei, 1998) using the formula given by (Thrusfield, 2005). The study considered 95% confidence interval and 5% precision level. Accordingly a total of 384 animals were calculated, but to increase precision, the number of examine animals were reached to 400. For this study sex, age, origin and body condition of animals were considered as risk factors.

A cross sectional study was conducted from November 2015 to June, 2016 by collecting data on events associated with hydatidosis in cattle slaughtered in Jimma municipal abattoir. This study was conducted to determine update information on the prevalence and economic impact on bovine hydatidosis at Jimma municipal abattoir. (Two slaughtering days per week) visits were made to abattoir.

Pre-slaughter examinations of cattle were conducted in the lairage in order to determine the sex, age, body condition and origin of animals. Identification number was given for each animal to examine after evisceration. During ante-mortem examination, animals were clinically examined for any sign of illness while standing and moving according to (Urquhart et al., 1996). And following the judgments passed by (FAO, 1994).

During post mortem examination organs especially liver, lung, spleen, kidney and heart as a whole were systematically inspected for the presence of hyatid cyst by applying the routine meat inspection procedure of primary examination followed by secondary examination. The primary examination involves visualizations and palpation of organs, were as secondary examination involves further systemic incision of each organs into pieces and whenever evidence of hydatid cyst was found, it was classified as live or calcified and the cyst distribution into organs was recorded.

Based on the presence or absence of brood capsules containing protoscolices in hydatid fluid, cysts were identified and classified as fertile and infertile according to the method described by Macpherson (1985). Individual hydatid cysts were carefully incised and examined for protoscolices, which resembled white dots on the germinal epithelium; such cysts were characterized as fertile cysts.

Fertile cysts were subjected to viability test. A drop of the sediment containing the protoscolices were placed on the microscope glass slide and covered with cover slip and observed for amoeboid like peristaltic movements with 40x objective. For clear vision, a drop of 0.1% aqueous eosin solution was added to equal volume of protoscolices in hydatid fluid on microscope slide with the principle that viable protoscolices should completely or partially exude the dye while the dead ones absorb it (Macpherson et al., 1985). Furthermore, infertile cysts were further classified as sterile or calcified. Sterile hydatid cysts were characterized by their smooth inner lining usually with slightly turbid fluid in their content. Typical calcified cysts produce a grittysound heard at incision (Soulsby, 1982).

An attempt was made to estimate the annual economic losses from hydatidosis in cattle taking into account losses from cost of organ condemnation and from carcass weight.The retail market price of average size offal (lung, liver, kidney, heart and spleen) and the cost of one kg beef were obtained from information gathered from local butchers. Annual economic loss due to organ condemnation was determined by considering annual slaughter rate of cattle and prevalence of hydatidosis per organ and an estimated 5% carcass weight loss (Getaw et

Phr-percent involvement of heart Cphr-current mean retail price of heart Pli-percent involvement of liver Cpli -current mean retail price of liver Psp-percent involvement of spleen Cpsp -current mean retail price of spleen. Pkid-percent involvement of kidney Cpkid -current mean retail price of kidney N: B-All prices are determined from the price at Jimma town.

Total economic loss was evaluated by considering both loss from organ condemnation and loss from carcass weight loss. Total loss = direct loss (loss from organ condemnation) + indirect loss (loss from carcass weight loss).

The data obtained was coded in Microsoft excel sheet 2007 and subjected to descriptive statistics and chi-square in order to assess the magnitude of the difference of comparable variables using SPSS version 20.0 software. Statistically significant association between variables is considered to exist if the p-value is less than 0.05.

Out of the total 400 heads of cattle slaughtered and examined, 218 (54.5%) were infected with hydatid cyst, more cysts involving different visceral organs (lung and liver). Rate of infection in different age groups (<5 and, 5-8 and >8 years) was assessed and described in (Table 1). Prevalence in age groups have shown as statistically highly significant variation (P<0.05, ?2 = 16.615) with young group having higher infections.

ii. Body condition score Prevalence was also assessed in terms of body condition score (Table 2). It was found that cattle having poor body condition had the highest prevalence (74%) followed by medium (46.6%) and good (52.5%). There was highly significant difference revealed between body condition scores (P<0.05, ?2=28.332) with poor animals groups having higher infections.

iii. Origin of animals Prevalence of Hydatidosis in cattle slaughtered at Jimma Municipal abattoir in origin of animals at Bilida (61%) was higher infected but, at Sarbo 43.5% was less infected (Table 3).

Overall distribution of cysts in different organs of cattle slaughtered at Jimma Municipal abattoir was described (Table 4). Of the 223 cattle positive, 200 (89.7%) had cysts merely in lungs, 20 (8.9%) in liver, 1 (0.45%) in kidney, 1(0.45%) in spleen, whereas, the rest of 1(0.45%) in heart infections involved organs.

Out of 98 organ infected by cysts to tested for fertility, 50(17.3%) cysts of lung, 45(54.87%) cyst of liver, 1(100%) cysts of kidney,1(100%) cysts of spleen, and 1(100%)cysts of heart origins had protoscolices detected and hence, fertile. Out of the total cyst counts, 98(26.2%) cyst counts are fertile, 216(57.8%) are sterile and 60(16%) calcified. Fertility status of cysts from different organs has shown, but the cysts of lung origin being highly fertile (Table 5).

Due to aesthetic value and to break the life cycle of the Echinococcus parasites infected organs are condemned. A total of lung, liver, kidney, spleen and heart were condemned due to hydatidosis with an economic loss of 89249.2ETB, 22312.3 ETB, 676.89 ETB, 225.63ETB and 676.89 ETB respectively. The direct and indirect economic loss was about 133140.91 ETB and 3249072 ETB respectively. The total annual financial loss due to bovine hydatidosis was estimated to be 3362212.9 ETB, (Table 6).

In the present study the prevalence of Bovine hydatidosis in Jimma Municipal abattoir was found to be 54.5% which was comparable with the results of other works conducted, this study was much higher compared to the prevalence reported at Jimma 31.44% (Tolossa et al,. 2009) and 22.4% (Moges, 2003), Konso 22.57% (Fikre, 1994), Adigrat 20.3% (Kebede, et al., 2009b) and Nekemte 31.19% (Feyissa, 1987). Much lower prevalence was also reported by Kebede, 2009b (7.5%) in Shire and Tsehaye, 1995 (7.2%) in Debre Birhan and also high in Asella 61.0% (Koskei, 1998), 62.96% around Bale Robe (Woubet, 1988), and 59.9% Bahirdar (Nebiyou, 1990).

The present prevalence rate was high (54.5%). This might be due to the abundance and frequent contact between the intermediate and infected final hosts. It could also be associated to slaughtering of aged cattle which have had considerable chance of exposure to the parasitic ova, backyard slaughtering of small ruminants and provision of infected offal's to pet animals around homesteads. Moreover, poor public awareness about the disease and presence of few slaughter houses could have contributed to such a higher prevalence rate.

Generally, variation among the prevalence of hydatidosis at different geographical location could be associated to the strain difference of Echinococcus granulosus that exist in different geographical locations (McManus, 2006). Additionally variation could be with age factors of the animals and other factors like difference in culture, socio-economical activities and attitudes to dogs and their population. Similar to the present finding, it was reported that cystic Echinococcosis infection was higher for older animals (Azlaff & Dakkak, 2006; Fayesa et al., 2010). Animals with more than eight years of age were found to be highly infected that stastically significant (P value < 0.05). This could be mainly due to the fact that aged animals have longer exposure time to Echinococcus granulosus eggs. In addition, older animals might have weaker immunity to combat against infection (Himonas, 1987). This finding is similar to the finding of Fikre Lobago (1994), Hagos Yihdego (1997), Umur (2003), Azlaf and Dakkak (2006) and (Esatgil and Tuzer, 2007).

The prevalence of hydatidosis by origin of slaughtered cattle was assessed and statistically significant difference (P value < 0.05) was found indicating that geographical regions play an important role in distribution of the cysts. This could be due to the difference in the socio-economic status and animal husbandry practices of community in all areas from where animals were brought for slaughter and frequent contact of animals with infected definite host.

The prevalence of hydatidosis among different organs involved in harboring of the cyst showed that lung was found to be the most commonly affected organ (50%) followed by liver (43%) and this was equivalent with Bizuwork (2013), 50.5% for lung and 40.6% for liver and also similar result of 54.5% and 43.5% was reported by Debas and Ibrahim (2013) on lung and liver respectively. This finding was higher than finding of Abunna et al., (2012) who reports 12.5% and 4.25% prevalence for lung and liver respectively while 92.7% in lung and 53.2% in liver which is higher than this study was also reported by Abera et al., (2013).

In this study number of cysts collected from lung 200(89.7%) was greater than that collected from liver 61(8.9%) and that of spleen, heart and kidney in which 1(0.45%) was recorded. Comparable results were reported by (Alemu and Yitagele, 2013), 47.04% and 44.2% for lung and liver respectively and 9.41% for spleen, heart and kidney. This might be due to the fact that cattle are slaughtered at older age, during the time the liver capillaries are dilated and most oncospheres directly pass to the lung; additionally, it is possible for the hexacanth embryo to enter the lymphatic circulation In direct Monetary loss Total Monetary loss=direct loss + in direct loss and be carried via the thoracic duct to the heart and lungs in such a way that the lungs may be infected before or instead of liver (Arene, 1985).

Additionally, the lung and liver which are most commonly infected organs, this could be due to the fact that lungs and livers posses the first great capillaries of sites encountered by migrating Echinocooccus onchosphere (hexacanth embryo) which adopt the portal vein route the first large capillaries encountered by migrating blood borne onchospheres and primarily negotiate pulmonary and hepatic filtering system sequentially before any other organ is involved. However, development of hydatid cysts occur occasionally in other organs like spleen, kidney and heart and other organs and tissues when onchosphers escaped into general systemic circulation (Urquhart et al., 1996).

Lung harbored highest number of calcified cysts (20.4%) followed by liver (1.2%). This finding is comparable with finding of Mesele et al. (2013) 60.2% ,22.6% and 4.3% respectively for lung, liver and spleen and higher than the report of Bizuwork et al.(2013) with the prevalence's of 36.8% for lung,14.6% for liver and 0% for spleen. This can be due to the host defence mechanisms of killing more efficiently the parasitic larvae at the early stage of development (Himonas, 1987).

The percentage of fertile cysts in this study was 26.2%. This is higher compared to the fertility rate of 26.9%, 24.4% and 19.3% reported by Fayesa et al.

(2010), Solomon (2011) and Zelalem (2008) respectively from different parts of Ethiopia. But the present study was quite lower compared to the 96.9% reported from South Africa (Arene, 1985). Yet much lower fertility record such as 1.76%, 9.85% and 6.2% were reported in cattle from Wolayita Soddo (Nigatu, et al., 2009), Nekemt (Bersissa, 1994) and Bahir Dar (Nebiyou,1990) respectively. The variation in fertility rates among different species and in different geographical Zones could be due to difference in strain of Echinococcus granulosus (McManus, 2006). Strain of the parasite and the host can modify the infective pattern of the parasite (Gemmel et al., 2002).

Comparison of fertile cyst from different organs was found to be lower for lung (17.3%) than liver (54.87%). This finding was agreement with finding of (Debele et al., 2014) 66.7 and 40.7% for lung and liver respectively and the present finding was higher than Debas and Ibrahim(2013) 25% and 7.5% for lung and liver respectively.

Out of a total 400 cattle carcasses, 218(54.5%) were infected with hydatid cysts. Of these cysts 98 (20%) fertile, 216(57.75%) sterile and 60(16%) were calci fied. Higher infected when compare with (Tolossa et al,. 2009) in Jimma out of a total 512 cattle, 161(31.44%) were infected with hydatid cysts. a total of 1171 hydatid cysts being collected from the infected animals. Of these cysts, 223(19.4%) were fertile, 505(43.13%) were sterile and 349(29.80%) calcified. These indicate that cattle are an important intermediate host for the perpetuation of the life cycle of the parasite in Jimma and its surroundings.

The annual economic loss incurred by hydatidosis was calculated to be 3362212.9 ETB. The result was relatively comparable with the report of (Zelalem, 2008) As described above Hydatid disease is generally considered to be a rural disease because of its way of transmission cycle, which involves domestic herbivorous animals (cattle, sheep, pigs and so on) and dogs. However, it is possible that urban residents may have been in contact with Echinococcus granulosus eggs, in this matter backyard slaughtering and inappropriate disposal affected organs plays major role for the continuity of parasite life cycle.

The overall prevalence observed in the study indicated relatively high and an important zoonotic disease in the area and this could be due to several factors of which keeping dogs in close association with cattle. Hydatidosis also causes substantial visible and invisible economic losses in cattle of the study area as a result of condemnation of edible offal and carcass weight loss. The most preferred predilection sites of hydatid cyst in cattle like liver, kidney, heart and lungs and condemnations of these important organs having a single or multiple hydatid foci is really a huge loss. From the result obtained in the present study and considering the reality in Jimma municipal abattoir and its surrounding, it is mandatory for launching a control program proper disposal of affected offal's freely for dogs and wild canids (the usual practice in the community) should be stopped and all the condemned organs should be either buried or incinerated. Moreover, further studies are needed on genotyping, epidemiology and public health importance of Echinococcus granulosus in the study area

The authors acknowledge Jimma University College of Agriculture and Veterinary Medicine (JUCAVM) for financing the project in the period from November 2016 to June 2016.