Abstract: A six weeks old native kid from a flock with history of diarrhea with or without mucus or blood, unthriftness, emaciation, weakness, anorexia and death was referred to Department of Pathobiology, Faculty of Veterinary Medicine, University of Shiraz. At necropsy, severe and diffuse white nodular lesions were present on the mucosal surface of jejunum. The direct smear of mucosal scrapings showed large number of oval oocysts. Histopatological examination of jejunal nodules revealed severe hyperplasia of the villous and crypt epithelial cells containing developmental stages of Eimeria species. In lesions exhibiting this hyperplasia, elongated crypts and long papillary fronds of villi were observed. In addition, very long extensions of tunica submucosa were seen between adenomatous mucosal surface. Gross and histopathological examination of jejunum is very important in post mortem diagnosis of intestinal coccidiosis in goats. In our study, macroscopic and microscopic lesions of coccidiosis in the jejunum were unique and very severe.
INTRODUCTION
Coccidiosis in goats is an important disease resulting from complex interactions between parasites and host, with many factors influencing the severity of disease (Koudela and Bokova, 1998). Coccidia are known to occur in organs other than the intestine including liver, bile ducts, gall bladder, hepatic and mesenteric lymph nodes in the caprine species (Dai et al., 1991; Lima, 1981; Mahmoud et al., 1994; Schafer et al., 1995). Various Eimeria species were identified in fecal samples of goats but E. arloingi and E. ninakohlyakimouae were considered to be the most pathogenic species (Koudela and Bokova, 1998; Norton, 1986; Vercruysse, 1982).
A six weeks old native kid from a flock with history of diarrhea with or without mucus or blood, unthriftness, emaciation, weakness, anorexia and death was referred to Department of Pathobiology, Faculty of Veterinary Medicine, University of Shiraz.
At necropsy, severe and diffuse white nodular lesions were present only on the mucosal surface of jejunum (Fig. 1). Duodenum, ileum, cecum and colon did not show any nodular lesions. The authors have frequently observed discrete nodular lesions due to coccidiosis (Fig. 2) in kids, but in the current case, the jejunal lesions were unique and very severe. The direct smear of mucosal scrapings showed large number of oval oocysts that confirmed coccidiosis. For histopatological examination of jejunal nodules, tissue samples were taken and fixed in 10% neutral buffered formalin. They were processed and embedded in paraffin. Sections of 5 μm thickness were cut and stained with haematoxylin and eosin.
Histopatological examination of jejunal nodules revealed severe hyperplasia of the villous and crypt epithelial cells containing coccidia. In lesions exhibiting this hyperplasia, elongated crypts and long papillary fronds of villi were observed (Fig. 3). Different developmental stages of the Eimeria life cycle especially sexual cycle were readily recognized within hyperplastic villous and crypt epithelial cells (Fig. 4). In addition, very long extensions of tunica submucosa were seen between adenomatous mucosal surface. A moderate infiltration of inflammatory cells including plasma cells, lymphocytes and macrophages were present in the lamina propria.
DISCUSSION
Coccidia are obligate intracellular parasites whose development within the cytoplasm of epithelial cells results in the death of affected cells. The total effect on the host depends on the magnitude of the initial infecting dose of oocysts, which determines the number of invaded cell and the spread of infection during schizogony, which is affected to a great extent by immunity acquired by the host (Jones et al., 1997).
| Fig. 1: | Severe and diffuse white nodular lesions are seen on the mucosal surface of jejunum |
| Fig. 2: | Discrete nodular lesions due to coccidiosis |
| Fig. 3: | Note elongated crypts lined with hyperplastic, tall columnar cells containing coccidia (H and E, x92.5) |
| Fig. 4: | Different stages of Coccidia especially oocysts are seen in the crypt epithelium and lumen (H and E, x 528) |
In this study, severe gross and histopathological lesions of coccidiosis were observed in the jejunum. Koudela and Bokova (1998) diagnosed clinical coccidiosis in kids 2 to 4 weeks after weaning and mortality rate reached 30%. At necropsy, macroscopic pathological lesions included mucosal hemorrhages and nodular polyps were found in the jejunum. E. arloingi and E. ninakohlyakimouae were identified as clinical coccidiosis cause (Koudela and Bokova, 1998). In our study, the causative Eimeria species was not identified. Jejunal lesions and well-delineated, coalescing area of hepatic coccidiosis were described in a case of naturally occurring coccidiosis in a goat (Schafer et al., 1995). Mahmoud et al. (1994) reported a hepatobiliary coccidiosis in a dairy goat, but intestinal lesions were observed only microscopically (Mahmoud et al., 1994).
In this case, histopatological examination of jejunal nodules showed different developmental stages of the Eimeria life cycle especially sexual cycle within hyperplastic villous and crypt epithelial cells. This finding is in agreement with Jones et al., 1997. In hyperplastic lesions, coccidia in various stages of gametogenesis are most numerous. This is in contrast to the erosive, hemorrhagic stages, in which organisms in various stages of schizogony are most common (Jones et al., 1997).
Gross and histopathological examination of jejunum is very important in post mortem diagnosis of intestinal coccidiosis in goats. In our study, macroscopic and microscopic lesions of coccidiosis in the jejunum were unique and very severe.
ACKNOWLEDGMENTS
The authors thank Mr. Shirvani and Mr. Khatami for their technical assistance.