CYSTICERCOSIS IN SMALL RUMINANTS SLAUGHTERED IN ASWAN SLAUGHTERHOUSE, EGYPT

Assiut University web-site: www.aun.edu.eg

CYSTICERCOSIS IN SMALL RUMINANTS SLAUGHTERED IN ASWAN SLAUGHTERHOUSE, EGYPT

AHMED K. DYAB¹; MOHAMMED E. MARGHANY ¹; RAGAA A.OSMAN ¹

and MAHMOUD A.AHMED ²

¹Department of Medical Parasitology, Faculty of Medicine, Assiut University

²Department of Parasitology, Faculty of Veterinary Medicine, Aswan University.

Received: 20 September 2017;       Accepted: 22 October 2017

INTRODUCTION

Metacestodes are the larval stages of the tapeworms inhabiting in intermediate hosts. The Middle East, southwestern Asia and the Mediterranean coast were considered of high endemic area for metacestodes infection. One of the most common metacestodes which found in infected slaughtered sheep is Cysticercus ovis which may lead to a disease in infected sheep called "sheep measles". Cysticercus ovis is the intermediate larval stage of canid tapeworm, Taenia ovis. The adult tapeworm lives in the intestine of domestic dogs and wild canids (Paula, 2009).

Another important and common metacestodes is Cysticercus tenuicollis which is the larval stage of Taenia hydatigena, a tapeworm of dogs and wild carnivores. The Cysticerci are found in the liver and on the peritoneum in sheep and also in other ruminants including wild ones and pigs. It is called also "long-necked bladder worm". The Cysticerciare most commonly found attached to the omentum, mesentery, live and peritoneum (Kaufmann, 1996).

Corresponding author: Dr. AHMED K. DYAB

E-mailaddress: ahmedsaf2001@yahoo.com

Present address: Department of Medical Parasitology, Faculty of Medicine, Assiut University.

The prevalence of infection is considerably high in the world in some countries even more than 85% of sheep population was found to be infected with this metacestode (Garcia-Marin and Peris-Palau, 1987). The present study was designed to study the prevalence and organ distribution of these metacestodes in slaughtered sheep and goats in Aswan Governorate, southern Egypt. Also the seasonal, age and sex relationship was determined. In addation to the histopathological and Scanning electron microscopy of cysticercus were stdied.

MATERIALS AND METHODS

Study area: This study was done from August 2015 to July 2016 in Aswan slaughterhouses of Aswan Governorate, southern Egypt.

Animals and post mortem examination: A total of 669 sheep and 484 goats carcasses of both sexes and of different age ranges slaughtered at Aswan slaughterhouse were examined. Visual inspection of the omentum, mesentery, peritoneal cavity, liver, lungs, kidneys, spleen, striated muscles, heart and subcutaneous area of each carcass was done for the presence of C.ovis and C.tenuicollis. Cysts were removed from the condemned organs by careful dissection from surrounding tissues without injuries to the wall of cysts. All the detected larval cestodes were collected in separate cellophane bags, then labeled and carried to the laboratory of Parasitology Department, Faculty of Veterinary Medicine, Aswan University in ice box container for further examination. Cysts wash thoroughly with distilled water and then keep in formalin 10% for histopathological examination, some cysts were used to the macroscopic and unstained process. Some cysts were kept in 5% cold buffered glutaraldehyde for the examination with scanning electron microscope. This examination was applied for studying the larval cestodes distribution and cyst characterization according to their location in different organs.

Data analysis:

Data were collected and entered into the computer using SPSS (Statistical Package for Social Science) program for statistical analysis. Data were entered as numerical or categorical, as appropriate. Two types of statistics were done: Descriptive statistics: Qualitative data were expressed as frequency and percent at 95% confidence interval (95% CI).

Analytical statistics: Chi-square test (X2) were used to measure the association between qualitative variables. P (probability) value considered to be of statistical significance if it is less than 0.05.

RESULTS

1. The infection rate and predilection seats of metacestodes in slaughtered animals:

Cysticercus ovis was detected (1.94%) from slaughtered sheep in Aswan slaughterhouse. The  survey of  slaughtered  goats  and sheep  revealed  a high infection rate  with Cysticercus tenuicollis  in goats (24.2%) and  was double  than  that  of  sheep (13.3%). Females of slaughtered sheep were more susceptible for C.ovis (2.63%) than males (1.59%). Moreover, Females of slaughtered sheep and goats were more susceptible for C.tenuicollis (28.5%) and (46.7%) than males (5.4%) and (20.9%), respectively. Sheep infected with C.ovis in young and aged animals were (1.18%) and (3.26%), respectively. Sheep and goat infected with C.tenuicollis in young and aged animals were (12.03%) and (15.5%), (24.1%) and (25%), respectively Table (1).

Table 1: The infection rate of metacestodes in slaughtered animals.

For Cysticercus ovis in sheep, the highest infection was found in spring (4.1%), followed by winter (1.9%) and summer (0.5%). The highest seasonal infection rate of Cysticercus tenuincollis in slaughtered sheep and goats was noted in autumn season (21.6%) and (73.7%), followed by winter season (12.4%) and (24.0%), while the lowest infection rate was recorded in spring and summer seasons (11.98% and 23.7%) and (11.6% and 14.3%), respectively Table (2).

Table 2: The infection rate of metacestodes in slaughtered animals in relation to season

For C.ovis in sheep, the infection was only found in the heart (100%). C.tenuicollis in slaughtered sheep and goats was found in the omentum (62.92%) and (67.52%), followed by mesentry (12.36%) and (21.37%), liver (11.24 %) and (11.11%), respectively. While urinary bladder (9%), diaphragm (2.25%) and lung (2.25%) were recorded in sheep and not recorded in goats Table (3).

Table 3: The predilection seats of Cysticercus tenuicollis in different organs.

II.Gross and microscopic examination of metacestodes in slaughtered animals.

DISCUSSION

1. The infection rate of Cysticercus ovis in slaughtered sheep:

Out of 669 examined sheep in Aswan slaughterhouse, the occurrence of Cysticercus ovis was (1.94%).This result is in agreement with those reported by Hashemnia et al. (2016) (1.27%) in Iran. While this result relatively higher than that previously reported by Ali (2013) (0.35%) in Qena, Egypt, Oryan et al. (2012) (0.09%) in Iran. However, this result is lower than those reported by Abdel-Maogood et al. (2005) (5.66%) in Cairo, in Egypt, White (1976) in western Australia, Sissay et al. (2008) in Ethiopia, Al-Qureishy (2008) in Saudi Arabia. In this study, C.ovis was not recorded in goats, while Sissay et al. (2008) in Ethiopia reported C.ovis infection in goats.

II. The infection rate of Cysticercus ovisin slaughtered sheep in relation to sex:

Females of slaughtered sheep (2.63%) were more susceptible to C.ovis infection than males (1.59%). There was no statistical difference for ovine cysticercosis in regards to sex (P>0.05). On the other hand, Hashemnia et al. (2016) reported that the infection rate of C.ovis in slaughtered sheep was significantly higher in males than females (P<0.05).

III. The infection rate of Cysticercus ovis in slaughtered sheep in relation to age:

Older sheep, over two years old, were more susceptible for Cysticercus ovis (3.26%) than younger animals, less two years old, (1.18%). While there were no statistically significance of C.ovis in slaughtered sheep with regard to age (P>0.05).

IV. The infection rate of Cysticercus ovis in slaughtered sheep in relation to season:

In regards to seasonal variation of Cysticercus ovis in sheep, the highest infection rate was found in spring (4.1%), followed by winter (1.9%) and summer (0.5%). There was no statistically significance of C.ovis in regards to seasons (P>0.05). This result was agreed with Hashemnia et al. (2016). While Al-Qureishy (2008) found that the highest infection rate (17.5%) was in autumn, followed by spring (14.3%), winter (9.7%) and the lowest was in summer (6.2%).

V. The infection rate of Cysticercus ovis in slaughtered sheep in relation to predilection seats:

The only predilection seats of Cysticercus ovis were in the heart of sheep (100%). This was agreed with Hashemnia et al. (2016), Gessese et al. (2015) in Ethiopia, Zheng (2016) in China.

VI. The infection rate of Cysticercus tenuicollis in slaughtered sheep and goats:

In this study, the overall infection rate of C.tenuicollis in 669 sheep and 484 goats slaughtered at Aswan slaughterhouse was (13.3%) and (24.2%), respectively. This result for slaughtered sheep and goats which infected with C.tenuicollis, respectively, was agreed with those reported by Omar et al. (2016) (16%) and (19%), in upper Egypt Governorates (Qena, Sohag and Aswan), Sultan et al. (2010), Abedl-Maogood et al. (2005), El-Dakhly (2007), Arafa and Fouad (2008) in Egypt, Radfar et al. (2005) in Iran and Scala et al. (2015) in Italy.

While it was higher than that reported by Mirzaei and Rezaei (2015) (4%) and (4.9%) in Iran, Bhaskararao et al. (2003), Singh et al. (2015) in India, Jayousi (2014) in Palestine. This result was lower than those reported by Abdulatif et al. (2015) (45%) and (53.9%), Sissay et al. (2008), Wondimu et al. (2011) in Ethiopia, Biu and Murtala (2012) in Sudan. While Braae et al. (2015) in Tanzania recoded wise infection rate of C.tenuicollis in sheep and goats (51.9%) and (45.7%), respectively.

The  infection  rate of  C.tenuicollis  was  higher  in goats as compared  to sheep  and  this  may be due to close contact between dogs and goats according to Torgerson et al. (1998). Also, this may due to protective immunity, which early developed in life for most sheep which was under conditions of high infestation of Cysticercus tenuicollis and this immunity regulate the parasite population, whereas goat develops the immunity more slowly. On the contrary, Pathak and Gaur (1982), Akinboade and Ajiboye (1983), Bhaskararao et al. (2003) and Sissay et al. (2008), who found  that  the  rate  of  infection  was  higher  in sheep  than in goats.

VIII. The infection rate of Cysticercus tenuicollis in slaughtered sheep and goats in relation to sex:

The infection rate of C.tenuicollis was higher in female sheep and goats (28.5%) and (46.7%) than male ones (5.4%) and (20.9%), respectively. There were very highly significant differences in infection rates with C.tenuicollis among slaughtered sheep (P<0.000) while among goats were not significant (P>0.05). This result agreed with Omar et al. (2016), Akinboade and Ajiboye (1983), Abu-Elwafa and Al-Araby (2008),Mirzaei and Rezaei (2015). On the other report carried by Senlik (2008) who found that the highest infection rate was observed in male animals (26%) compared to females (23.9%). Moreover, Jayousi (2014) found that the sex wise infection rate was lower in females of sheep (2.7%) as compared to male ones (2.15%).

IX. The infection rate of Cysticercus tenuicollis in slaughtered sheep and goats in relation to age:

The infection rate of C.tenuicollis was higher adult sheep and goats (15.5%) and (25%) than in the young ones (12.03%) and (24.1%), respectively. There were no significant differences in infection rates among slaughtered sheep and goats in regard to age (P>0.05). This result agreed with Akinboade and Ajiboye (1983), Pathak and Gaur (1982), Bhaskararao et al. (2003), Abu-Elwafa and Al-Araby (2008), Senlik (2008), Abdulatif et al. (2015), Mirzaei and Rezaei (2015), Wondimu et al. (2011) and Omar et al. (2016). While Jayousi (2014) reported that the infection rate of C.tenuicollis was higher in young sheep (4.1%) than the older ones (1.9%). The highest infection rate in older animals than in younger ones might be due to decreased immunity in older animals than younger ones Bhaskararao et al. (2005). Moreover, may be due to close contact between older animals and dogs as mostly of young animals kept indoors than older animals.

X. The infection rate of Cysticercus tenuicollis in slaughtered sheep and goats in relation to season:

According to seasonal dynamics of Cysticercus tenuicollis, the infection rate in sheep and goats, respectively, was higher in autumn (21.6%) and (73.7%), followed by winter (12.4%) and (24%). C.tenuicollis infection with regard to season, there was very highly significant differences in goats (P<0.0001) while among sheep non-significant (P>0.05). This result was agreed with Abu Elwafa and Al-Araby (2008).

XI. The infection rate of Cysticercus tenuicollis in slaughtered sheep and goats in relation to predilection seats:

The infection rate of C.tenuicollis in different organs of sheep and goats showed that the most predilection seats of the cysts were in omentum (62.92%) and (67.52%), followed by mesentry (12.36%) and (21.37%), liver (11.24 %) and (11.11%), respectively. While u rinary bladder (9%), lung and diaphragm with the same lowest percentage (2.25%) for each. The difference between the infection rate of omentum and other organs was very highly significantly associated (P<0.0001). This is in agreement with Gessese et al. (2015), Abu-Elwafa and Al-Araby (2008), Radfar et al. (2005), Wondimu et al. (2011), Biu and Murtala (2012), Omar et al. (2016), Abdulatif et al. (2015), Fahmi (2014). While Mirzaei and Rezaei (2015) found that the liver wasthe highest infection rate for C.tenuicollis in slaughtered sheep and goats (1.64%) and (2%), respectively.

Cysticercus ovis appear as small whitish cysts filled with fluid that contain an immature worm this was agree with Omar et al. (2016).The cyst have the size of a grain rice (~4 to 9 mm). Infected meat can have dozens of such cysts. Cysticercustenuicollis in goat was contained fluid and appears scolex inside it. Omentumgross lesions included accumulation of a large quantity of serofibrinous fluid in the peritoneal and thoracic cavities and a large number of small-sized cysts floating in the fluid of the peritoneal cavity. Cysticercustenuicollis stained with H&E stain showing the cystic membrane of C.tenuicollis surrounded by a zone of inflammatory cells and fibroblasts. This agree with Abdulatif et al. (2015), show that the C. tenuicollis hemorrhagic streaks large concentric foci of hemorrhage in the hepatic parenchyma in the migration stage were observed. In histopathological examination, decreased number of hepatocytes, dilution of sinusoids presence of inflammatory cells in portal areas and double layered parasitic cyst formation in chronic stages were evident. Scanning electron microscopy showing scolex of Cysticercus tenuicollis scolex which appears with circular striations in construction and a cap tegument covered the scolex. The bladder wall consists of two main layers. Scanning electron microscopy showed that the outer surface of the bladder is a rough surface consisting of numerous sparsely situated microthriches with no apparent pattern of distribution. They are long and fineas a result of which they are intert wined, forming some thing like a network among which closedareas, lagoons, are formed this agree with Abu-Elwafa and Al-Araby (2008) The thin elongated microthriches are in most cases connect­ed with anther by transverse connections sheep measles (Cysticercus ovis) cause condemnation of carcases or parts of carcases at abattoirs, but they rarely cause ill-effects in the sheep or goats. Small white cysts appear in certain muscles, and while these cannot infect humans, they are considered unacceptable, leading to carcase condemnation. Any affected organs (e.g. hearts) are condemned and cysts are trimmed from muscle in light infections.

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