Hydatidosis as a major cause of liver condemnation among parasitic diseases in goats and sheep in Keren slaughterhouse , Anseba zone , Eritrea

Aim: To find out the prevalence of hydatidosis and the number of livers condemned due to this disease using retrospective data from municipal slaughterhouse in Keren, Eritrea. Materials and Methods: A retrospective data of ten years (1999 to 2008) on slaughtered goats and sheep was collected from Keren Municipal slaughterhouse, Anseba Zone of Eritrea. The data was analyzed for the prevalence of hydatidosis and the number of livers condemned. Besides, condemned livers from sheep and goats due to the presence of hydatid cysts were collected (September to December, 2008, and from March to July, 2009) for gross examination and microscopic pathology. Result: Our findings indicated that among the parasitic diseases encountered in the slaughtered animals, hydatid cysts were the most prevalent ones. Conclusion: This study has depicted that the major contributor for liver condemnation was hydatidosis. Moreover, the study has shown that the trend of the prevalence of hydatidosis is increasing and this warrants immediate intervention for its control.


Introduction
echinococcosis in human and animal hosts is found in countries of the temperate zones, including several Livestock is a very important component in the parts of Eurasia (the Mediterranean regions, southern agricultural production system in Eritrea.It plays a and central parts of Russia, central Asia, China), significant role in the livelihood and the GDP of the Australia, some parts of America (especially South country [1].Sheep and goats are vital components of America) and north and east Africa.Echinococcosis is the agricultural system of the country.However, they currently considered an endemic zoonotic disease in are affected by hydatidosis which has both economic the African region [7][8][9].and zoonotic importance [2][3][4].In Eritrea, because of Thus, it is imperative to have data regarding the the unpredictable and low rainfall, cropping is often at major diseases prevalent in a given place in order to risk in the arid and semi-arid areas.Hence, sheep and take effective control measures.Besides, it is also goat production under pastoral system is a very good important to find out the diseases shared by both way of compensating the failing crop in most parts of animals and humans.For this purpose, slaughterhouses the country.Moreover, this type of production system are a very good data source for both the diseases of could be a reliable potential source of livelihood public health and economic importance.Slaughterprovided that effective disease control measures are house disease surveillance is considered to be an undertaken.Among the many constraints, disease and important method for confirming diagnosis, diseases parasites are of major importance.According to the control and eradication campaigns worldwide [10].Ministry of Agriculture's Annual reports (1999)(2000)(2001)(2002)(2003) In the current study, disease surveillance in a [5], in Eritrea, 70-80 % of the health problems in small slaughterhouse was considered an alternative method ruminants were estimated to be due to internal and to investigate the parasitic disease of economic and external parasite infestation.
zoonotic importance.The study was conducted in Hydatidosis (Echinococcosis) is an important sheep and goats slaughtered at Keren slaughterhouse in public health problem in many parts of the world, Anseba Zone, Eritrea.Keren is the main town of especially in rural areas where sheep, goats and cattle Anseba Zone, located 90 kms, North-West of Asmara, are raised [2,6].The greatest prevalence of cystic the capital city of Eritrea, and lies about 1800 meters above sea level.The purpose of the study was to find out the presence of hydatid cysts and the number of organs condemned due to the cysts.

Materials and Methods
can be estimated.The average prevalence (Pr) of the parasitic diseases (Hydatidosis), as a representative for A retrospective data of ten years (1999 through each year, can be expressed as the proportion or 2008) was collected from Keren slaughterhouse, Anseba percentage of the condemned organs (TNO) resulting Zone, Eritrea.Moreover, condemned organs were from Hydatidosis to the total number of animals collected on a weekly basis for gross pathology and slaughtered [12].microscopic examination (September -December, Pr = (TNO/TNA) x 100% 2008, and from March -July, 2009).The data was This study has emphasized on the number of collected to find out the prevalence of Hydatidosis and livers condemned due to Hydatidosis.the number of organs condemned due to the presence of To show the trend of prevalence throughout the Hydatid cysts.Besides, the data collection has record period, annual prevalence rate was also calculated.considered the number of animals slaughtered during the study period (1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008).

Results
During the ten years of record in the slaughter-Statistical analysis: The collected data was analyzed house of Keren town, a total of 155,721 animals of using statistical packages such as SPSS version 11 which 92% goats, 7% Cattle and 1% sheep were software and Microsoft excel.
slaughtered.The sources of the slaughtered animals A linear regression model was employed to analyze were the surrounding sub-zones with similar climatic the trend of slaughtered animals and condemned condition to Keren town.High number of slaughter organs throughout the record period.To validate the was recorded in the year 2001.The annual number of significance of the coefficients that explain the rate of animals slaughtered on average was 15,572 with change per unit time (year) or trend, the standard errors standard deviation + 7,231, and range 7,048 to 24,817.(SE) and t-statistics (t-test) were used.Means, standard Regression of total number of animals slaughtered deviations, ranges and percentages were also used (TNA) on time period (T) depicted that on average when necessary.
there was an annual decrease in the number of animals Once more, the total number of organs (liver in year to year.The coefficient of determination r shows particular) condemned (TNO) was also regressed that 87% of the variation in the number of slaughters is linearly against time (T) to identify the trend (average due to variation in time (year).yearly increase or decrease) in the number of Figure-1 shows the average annual number of condemned (livers) organs as follows: animals slaughtered decreased from year to year.TNO = f(T) The total number of livers condemned due to TNO = α α T ……….[eq.2]a Hydatidosis during the ten years was 5,345.The annual The slope coefficient α indicates an average mean and standard deviation respectively were 2 estimate of the trend in the number of organs (liver) estimated to be 534 and 144, with a range of 304-818.condemned each year due to Hydatidosis [11].By High numbers of condemned organs were found in the comparing [Eq.1]a, the trend of animals slaughtered, year 2001.and [Eq.2]a, the trend of organs condemned; the The total number of organs (livers) condemned prevalence of parasitic diseases (such as Hydatidosis) (TNO) was once more regressed against time (year) (T).This depicted that on average only two organs cysts, three distinct layers (structures) were demons-(liver) less, which is statistically insignificant, were trated, namely; an outer pericyst, a middle laminated condemned than the preceding year.membrane, and an inner germinal layer [13].TNO = 545.6

-2.04T ……… [Eq. 2]b
Microscopic examination: Fine needle aspiration from Se = (104.48)(16.840) the collected hydatid cysts has demonstrated clearly t = (5.22)(-0.12) the presence of hydatid sands (Figure -3).Normally, for a decreasing number of animals Discussion slaughtered each year and hence less number of animals tested year by year, one expects less number of Echinococcosis, which is often referred to as organs condemned.Neverthless, the finding indicates a hydatid disease or echinococcal disease, is a parasitic slight increase in the number of organs condemned disease that affects both humans and other mammals, even if the tested animals were decreasing in number.
such as sheep, dogs, rodents and horses [14].The This implies logically an increasing number of the worldwide incidence and prevalence of cystic echinocondemnation of affected organs and hence an coccosis has reduced considerably over the past several increasing trend or prevelance of the disease throughdecades.Nevertheless, infection with Echinococcus out the tested period of ten years.Moreover, this trend granulosus remains a major public health issue in also indicates that no attempt has been made to control several countries and regions due to lack of control hydatidosis in the country.
programmes, economic problems and lack of resources Table-1 and Figure-2 depicts that the prevalence [15]. of hydatidosis increased from year to year whereas the In the present study, the average prevalence number of animals slaughtered (tested) decreased.
expressed as a proportion of the number of livers condemned due to Hydatidosis to the total number of

Gross pathology and microscopic examination
Gross pathology: Gross pathology of the collected slaughtered animals was 3.4%.This prevalence rate is organs demonstrated typical lesions with fluid filled not very high when compared with other studies [16].cysts on the livers.Upon incision of the fluid filled Nevertheless, it is worth noting that pathological lesion    of the affected livers causes considerable loss to affected 30,202.64USD in Wolaiyta Sodo and 138,202.64USD organs (livers) due to partial or complete condemin Hawassa, municipal abattoirs, in Southern Ethiopia, nation of the affected parts.One of the major limitations were reported, respectively [28,29].Moreover, a study of the present study was the absence of the registration conducted in slaughtered sheep and goats in Addis of ages of the animals in the slaughterhouse.When Ababa municipal abattoir indicated a total financial undertaking surveillance work with E. granulosus in loss of 20,822.40USD (270,691.34Ethiopian Birr), intermediate hosts, it is very crucial that data are mainly due to carcass weight loss and condemnation of stratified and reported according to the age of animals organs [30].These findings from neighboring Ethiopia slaughtered.Prevalence rates are strongly age might also be true in Eritrea, where similar livestock dependent and Hydatidosis is more common in aged husbandry systems are practiced, though our study animals [17][18][19][20].But considering the prevalence rates hasn't attempted to estimate the economic loses.observed in our study, it can be assumed that many To control hydatidosis, apart from deworming of young animals were being slaughtered during the record intermediate hosts, proper disposal of affected organs time.Thus, the true situation of hydatidosis might have and offals, vaccination can also be considered in areas been under-represented.The presence of hydatid cysts where there is a high prevalence of Hydatidosis.Recent was reported to be relatively higher in lungs than in findings have indicated that progress has been made in liver [16,21,22].However, the current study has found the development of an effective vaccine against infection that liver is the organ that is more frequently affected with the larval stage of E. granulosus in sheep and than the lungs.This finding is in agreement with the cattle [17].Experience of a country like Cyprus has studies conducted somewhere else in Kenya [23], shown the possibility of successful implementation of Turkey [18] and Egypt [24].
eradication programs of Echinococcosis [8].It is worth In this study it was difficult to precisely trace back mentioning that lack of control programs, resources, the geographical origins of all animals slaughtered due and economic problems are the major culprits that to lack of reliable animal identification method.make E. granulosus to remain a public health and Therefore, relating the findings of the study to a precise economic concern [15].The public health issue localities is difficult.However, it is known that almost requires a serious consideration in this country.all the animals slaughtered came from the traditional Conclusion livestock production system.In the traditional livestock Hydatidosis is an important disease that leads to husbandry system keeping dogs along with livestock is high liver condemnation in Keren municipal slaughtera very common practice.Echinococcus granulosis is house, Eritrea.As this was the first slaughterhouse reported to be a common finding in dogs from all substudy of its kind for the region (Anseba region) that Saharan countries [4].Thus, the presence of nomadic indicated the prevalence and economic significance of or semi-nomadic goat and sheep population that represent the intermediate host of the parasite, and their close the disease, further study on the epidemiology of the contact with the final host, the dog, might increase the disease, covering larger areas is required for establishrisk of transmission of infection to humans.Camel and ment of an effective control program.Further studies cattle are also reported to be the principal intermediate need to be initiated at the definitive host (dog) level, so hosts of the disease [25].However, in regards to which as to have a complete picture of the disease and to of the intermediate hosts are crucial in disseminating design appropriate control measures.the disease seems to vary from study to study [26].

Therefore, in Eritrea, immediate intervention
This study was fully funded by the Hamelmalo through deworming of dogs and treatment of affected Agricultural College.The authors are grateful to the animals is mandatory.It will also be wise to investigate Dean and Associate Dean (Academic Affairs) of the role of wildlife in harboring and transmitting Hamelmalo Agricultural College, Eritrea, for their hydatidosis to other susceptible animals [27].The support during this study.The authors are also very economic importance of hydatidosis was reported in thankful to the Municipal Slaughterhouse of Keren, recent studies conducted in slaughtered cattle in particularly, to Mr. Yohanness, the senior meat inspector.Ethiopia.In these studies annual economic loses of

Figure- 1 :
Figure-1: Trend of the number of animals slaughtered in ten years time (1998 -2010).

Figure- 2 :
Figure-2: Trend of the number of animals slaughtered and the prevalence of Hydatidosis in ten years.