World Journal of Zoology 3 (1): -35, 2008 ISSN 1817-98 IDOSI Publications, 2008 Hepatic Coccidiosis of the Domestic Rabbit Oryctolagus cuniculus domesticus L. in Saudi Arabia Ebtesam M. Al-Mathal Department of Zoology, Girls College of Science, King Faisal University, Dhahran 31311, P.O. Box 10185, Saudi Arabia Abstract: Four hundred and ninety domestic rabbits (Oryctolagus cuniculus domesticus L.) were examined for hepatic coccidiosis using faeces and liver samples. Of the examined rabbits, 32.24 % were infected with the parasite Eimeria stiedae, the major causative agent of this disease. Various developmental stages of the parasite were observed in the liver and the bile duct. Numerous and scattered white nodules were recorded on the liver surface of infected rabbits. Histopathological lesions in the liver showed the following symptoms: severe congestion and dilation of central veins, rupturing of the lining endothelial, hyperplasia of the lining epithelial of portal areas with finger-like projections in lumen of the bile duct, congestion and dilation of sinusoids with haemorrhage areas. Multiple areas of coagulative necrosis of hepatic cells surrounded with inflammatory cells were found. The prevalence of infection and the effect of host age and sex on the rate of infection are discussed. Key words: Coccidia Eimeria pathology host age and sex INTRODUCTION In recent years, there has been increasing commercial production of rabbits as a source of protein. The consumers prefer rabbits for their low cholesterol and fat contents [1]. Therefore, rabbit production became one of the imp ortant animal resources in Saudi Arabia. In addition to this commercial value, these animals are used as very important models for medical research and as pets [2]. Coccidiosis is a ubiquitous protozoan infection of animals seriously impairing their growth and food utilization [3], it causes significant mortality in domestic rabbits [4, 5]. The coccidia of rabbits have not been studied to the same degree as the species which occur in other hosts. Hepatic coccidiosis (Eimeria stiedae) is one of the most pathogenic coccidian protozoans in domestic rabbits causing severe coccidiosis and increased mortality [4, 6-8]. Most of the research indicates that there is a strong relationship between the infection of coccidiosis and the host age; they believe that the infection decreases with increasing age of the host [9]. In Saudi Arabia there is lack in information about this parasite; a few studies only were reported [10-13]. The aim of the present study was to investigate prevalence of E. steidae in domestic rabbits in the Eastern Province in Saudi Arabia and to establish the relationship between age and prevalence of infection in young rabbits. The results will increase our basic information on the current situation of this disease and for future research and to develop the appropriate control strategy for this disease either in rabbits or in other domestic animals of economic importance. MATERIALS AND METHODS Four hundred and ninety domestic rabbits 1-4 months old (as determined by farm veterinarians) were collected from three farms in the Eastern Province of Saudi Arabia. Farm A uses small wood portable rearing batteries with 100-150 rabbit battery. Farms B and C use big aluminium rearing batteries with 1000-1500 rabbit/battery. All farms feed rabbits on different dry cereals (e.g. corn, rice, etc.). Faecal samples from the collected rabbits (females and males) were examined by centrifugal flotation with saturated sugar solution to detect E. stiedae oocysts according to the method of [14]. Collected oocysts were mixed with 2.5% potassium dichromate for sporulation of oocysts according to the method of [13]. Infection-positive andnegative rabbits were dissected (subjected) for internal examination according to the method of [5]. Each liver and gall bladder was remo ved and inspected for nodules typical (characteristic) of infection with E. stiedae. Smears for nodules and sediments of bile were also examined. After the complete necropsy, tissue specimens from the liver were collected and fixed in 10% formalin for the histopathological studies as Corresponding Author: Dr. Ebtesam M. Al-Mathal, Department of Zoology, Girls College of Science, King Faisal University, Dhahran 31311, P.O. Box 10185, Saudi Arabia
described by [5]. After proper fixation, tissue blocks were embedded in paraffin. Thin (5 micron) sections were routinely prepared and stained with haematoxylin and eosin. 33.5 33 32.5 33.46 32.24 32 RESULTS 31.5 31 31.02 A total of 490 of 1-4 months rabbits were examined in this study, 245 males and 245 females. The results revealed that 158 (32.4%) rabbits were infected with E. stiedae. Of these rabbits, 76 males (31.02% of total males examined) and 82 females (33.47% of total females examined) were infected, but with no significant difference in incidence of infection between males and females (P<0.562) (Table 1 and Fig. 1). The highest prevalence of infection was in the two-months age group (46.31%) followed by the three-months group (45.26%) (Table 2 and Fig. 2). The examination revealed that single infection (55.06%) with E. stiedae was more frequent than mixed infection (44.93%) with other Eimeria species Table 1: Percentage infection of the coccidian parasite Eimeria steidae in both sexes of the domestic rabbit in Saudi Arabia Animal Examined Infected sex animals animals Percentage Male 245 76 31.02 Female 245 82 33.46 Total 490 158 32.24 *Not significantly different, (p < 0.562).5 29.5 Fig. 1: 50 45 40 35 25 20 15 10 Fig. 2: 5 0 Male Female Total Percentage infection of the coccidian parasite Eimeria steidae in both sexes of the domestic rabbits in Saudi Arabia 23.41 46.31 45.26 24.51 One month Two month Three month Four month Percentage infection of the coccidian parasite Eimeria steidae in different age groups of domestic rabbits in Saudi Arabia Table 2: Percentage infection of the coccidian parasite Eimeria steidae in the different age groups of the domestic rabbit in Saudi Arabia Animal Examined Infected age animals animals Percentage One 205 48 23.41 Two 95 44 46.31 Three 95 43 45.26 Four 95 23 24.51 Total 490 158 32.24 Table 3: Percentage infection of the coccidian parasite Eimeria steidae in the domestic rabbits collected from different farms in Saudi Arabia Examined Infected Farm animals animals Percentage A 178 61 34.26 B 170 63 37.05 C 142 34 23.94 Total 490 158 32.24 40 35 25 20 15 10 5 0 34.26 37.05 1 2 3 23.94 Fig. 3: Percentage infection of the coccidian parasite Eimeria steidae in the domestic rabbits collected from different farms in Saudi Arabia (P<0.072). Positive specimens were obtained from all three studied farms as shown in Table 3 and Fig. 3 (P<0.065). Developmental stages of the parasite Eimeria stiedae The unsporulated oocyst: The oocysts are narrowly oval in shape with cap and smooth wall, each contains 31
Fig. 4: Unsporulated oocysts of Eimeria steidae isolated from the domestic rabbits infected with hepatic coccidiosis (X 500) Fig. 7: Presence numerous protozoan stages including macrogamytocytes and oocyst of Eimeria steidae in rabbits infected liver. Heamatoxylin Fig. 5: Sporulated oocysts of Eimeria steidae isolated from the domestic rabbits infected with hepatic coccidiosis (X 533.33) Fig. 8: Central vein dilated and congested with ruptured of lining endothelial in the rabbits infected with Eimeria steidae. Heamatoxylin Fig. 6: Irregular yellowish nodules on the liver of domestic rabbits infected with hepatic coccidiosis (Eimeria steidae) Fig. 9: Hyperplasia of the epithelial cells of the billary duct in liver of Eimeria steidae infected rabbits. Heamatoxylin 32
Fig. 10: Congested and dilated sinusoids with haemorrhagic areas in Eimeria steidae infected rabbits. Heamatoxylin Fig. 12: Lymphocytes infiltration in the liver of rabbits infected with Eimeria steidae. Heamatoxylin rabbits was seen. The liver was pale and enlarged with irregular yellowish nodules and elongated dilated bile ducts on the surface (Fig. 6). Fig. 11: Coagulative necrosis of hepatic cells surrounded with inflammatory cells in rabbits infected with Eimeria steidae. Heamatoxylin an undeveloped zygote surrounded by yolk cells. This stage present in the rabbit faces after the infection and measure 0.03 mm by 0.01-0.02mm (SE 0.001) (Fig. 4). The sporulated oocyst: Sporulated oocyst is the infective stage of coccidian parasites. It s oval in shape with cap and double wall, each contains four sporocysts. Each sporocyst is 0.01 mm in length and containing two sporozoites. In this stage, the sporulated oocyst measures 0.03 mm in length by 0.01-0.02 mm (SE 0.0016) (Fig. 5). Macroscopical examination: On necropsy, a clear serous transudate fluid within the abdomen of infected Microscopic examination: Coccidian parasites were detected in various stages of development around the granulomatous lesion of the bile duct (Fig. 7). In histopathological analysis, severe congestion and dilation of central veins were observed and the lining endothelial were ruptured (Fig. 8). Severe hyperplasia of the lining epithelium of the portal areas were detected forming finger-like projections in the lumen of the bile duct (Fig. 9). Sinusoids were also congested in this connection and dilated with haemorrhagic spots (Fig. 10). Multiple areas of coagulative necrosis of hepatic cells surrounded with inflammatory cells (Fig. 11). In addition, cellular infiltration of lymphocytes in the infected liver was also observed (Fig. 12). DISCUSSION Hepatic coccidiosis in domestic rabbits were reported throughout the world [15]. The present study records the most important coccidian parasite of domestic rabbits, E. steidae in the Eastern Province of Saudi Arabia. In general, 32.24% of examined rabbits were infected with E. stiedae. This reported rate of infection is considered high compared with other studies in Saudi Arabia,where seven Eimeria species were reported from the central, eastern and western regions, but none of them was E. stiedae [10]. The infection rate increased to 25% in Jeddah, in the western region [11]. Compared to other countries in the Middle East such as Syria, where the infection rate was only 4% [4]. This variation in infection rates is 33
explained by the difference in environmental conditions prevailing in each region, the rearing conditions and the number of samples examined and the season of the year of the study. The prevalence of infection in males and females was very similar, that recorded 31.02 and 33.46%, respectively, with no significant difference (P<0.562). This result is comparable with the results obtained by [16]. It is almost known that hepatic coccidiosis which caused by E. steidae is a primary disease of young rabbits. Coccidal infection is affected by the host age; the highest incidence was in 2-months rabbits and then the infection rate decreased as the age increased. The high level of susceptibility of infection in young rabbits may be due to their immune, feeding and reproductive status. This observation is consistent with the results previously reported [9, 16-18]. Mixed infection with different species of Eimeria is common in rabbits. In this study, single infection with E. steidae (55.06%) was higher than mixed one (44.93%), which contradicts the results of previous reports in Saudi Arabia and other countries [4, 10, 11]. From results, farm B had the highest prevalence of infection (37.05%) followed by farm A (34.26%) and farm C (23.94%). This variation can be due to the high number of animals in this farm; these animals tend to congregate in large groups in separate parts of the farm which encourages wider spreading of infection in the herd. This hepatic coccidiosis caused severe damage to the liver and it is more pathogenic in young rabbits and led to death among these animals [9]. Histopathological observations in this study are in agreement with those described by others [5, 12, 13]. These histopathological lesions confirmed the results of parasitological examination of faeces which revealed the presence of large number of oocysts [5]. For a better and more efficient mo nitoring of infection of rabbits with hepatic coccidiosis, modern molecular diagnostic techniques such as the polymerase chain reaction should be combined to conventional methods. The proper management and programmed husbandry will reduce infection rate. ACKNOWLEDGEMENTS The author thanks Hanadi Baghdadi (Girls College) for collecting samples of this work. REFERENCES 1. Al-Husseini, M.A., 1992. Advanced way for rabbit production. Published by Ebin Sena library, Cairo, Egypt. 2. Yousif, O.M.A. and J.A.M. Abdul-Aziz, 1995. Commercial rabbit production. Published by Al- Dar Al-Arabia, Cairo, Egypt. 3. Abdel-Megeed, K.N., N.M. Abu El-Ezz and E.H. Abdel-Rahman, 2005. Protective effect of Eimeria stiedae coproantigen against hepatic coccidiosis in rabbits. J. Egypt. Soc. Parasitol., 35 (2): 581-595. 4. Darwish, A.I. and V. Golemansky, 1991. Coccidian Parasites (Coccidia: Eimeriidae) of domestic rabbits (Oryctolagus cuniculus L.) in Syria. Acta Protozool., 31: 209-216. 5. El-Akabawy, L.M., K.A. Zayan, A.A. Tantawy and R.E.M. Omar, 2004. Anticoccidial efficacy of propolis and Toltrazuril against Eimeria stiedae in New Zealand White Rabbit s. Zag. Vet. J., 32 (1): 129-145. 6. Sanyal, P.K. and S.C. Sharma, 1991. Clinicopathology of hepatic coccidiosis in rabbits. Indian. J. Anim. Sci., pp: 924-928. 7. Aly, M.M., 1993. Development of Eimeria stiedae in a non-specific host. J. Egypt. Soc. Parasitol., 23 (1): 95-99. 8. Hauptman, K., F. Tichy and Z. Knotek, 2001. Clinical diagnostics of hepathopathies in small mammals: Evaluation of importance of individual methods. Acta Vet. Brno., 70: 297-311. 9. Wang, J.S. and S.F. Tasi, 1991. Prevalence and pathological study on rabbit hepatic coccidiosis in Taiwan. Proc. Natl. Sci. Counc. Repub. Chin. B., 15 (4): 240-243. 10. Kasim, A.A. and Y.R. AL-Shawa, 1987. coccidian in rabbits (Oryctolagus cuniculus) in Saudi Arabia. Inter. J. Parasitol., 17 (4): 941-944. 11. Toula, F.H. and H.H. Ramadan, 1998. Studies on coccidia species of genus Eimeria from domestic rabbit (Oryctolagus cuniculus domesticus L.) in Jeddah, Saudi Arabia J. Egypt. Soc. Parasitol., 28 (3): 691-698. 12. Khalifa, S.A.M., R.A.A. El-Elyani and F.H.S. Toulah, 1998. The effect of dried leaves water suspension of neem plant (Azadirachta indica) on some organs of Rabbits (Oryctolagus cuniculus L.) infected by coccidiosis (Eimeria stiedai) 1. Some cytological, histological and histochemical studies on the liver. Egypt. J. Histol., 21 (1): 19-32. 13. Toula, F.H., 2000. Efficacy of water Suspension of Dried leaves of neem (Azadirachta indica) in the Control of hepatic Coccidiosis in Rabbit (Oryctolagus Cuniculus) in Jeddah (Western Region of Saudi Arabia). J. Egypt. Ger. Soc. Zool., 33: 107-128. 14. Heelan, J.S. and F.W. Ingersoll, 2002. Essentials of human parasitology. Delmar, United states. 34
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