Eosinophilic myositis and muscular sarcocystosis in the carcasses of slaughtered cattle and lambs

Fifty-three bovine and 7 ovine carcasses condemned for having eosinophilic myositis were evaluated. Four (7.3%) of the bovine carcasses had a few, large local lesions in skeletal muscles (category A), and 49 (92.7%) of the bovine carcasses and 7 (100%) of the ovine carcasses had multiple, small, disseminated lesions in tongue, esophagus, heart, diaphragm, or skeletal muscles (category B). Tissue from carcasses of category B were evaluated for bacteria, viruses, selenium, and pathologic changes. Pathogenic bacteria and viruses were not isolated and selenium concentrations were normal. In category B, all carcasses had granulomas; of the 49 bovine carcasses and 7 ovine carcasses, 38 (77.6%) and 7 (100%), respectively, had one or more granulomas with opened dead sarcocysts. The data indicated that opened sarcocysts killed the host myocyte and adjacent myocytes and stroma, thereby initiating granuloma formation.     

Intramuscular inoculation of cattle with Sarcocystis antigen results in focal eosinophilic myositis

Bovine eosinophilic myositis (BEM) is a subclinical myopathy characterized by multifocal white to grey-green discolorations in skeletal muscles, heart, tongue and oesophagus. These lesions are found at slaughter or during meat cutting and result in considerable economic losses. The etiology and pathogenesis are unclear, although it has been suggested, that Sarcocystis species are involved. To elucidate their role, two calves were repeatedly injected intramuscularly with adjuvanted Sarcocystis antigen. The morphological changes at the injection sites in these calves were histologically and immunohistochemically compared to spontaneous lesions from 44 BEM condemned carcasses sampled in slaughterhouses. Experimental intramuscular injection of Sarcocystis antigen resulted in lesions at the injection sites that were similar to the lesions of natural cases of BEM. They were characterized by massive infiltration of eosinophilic granulocytes, reactive macrophages (MAC387(+) cells), T-cells (CD3(+)) and B-cells (CD20(+)). Both in the experimental and in the natural cases, COX-2 expression was present in endothelial cells adjacent to lesional areas. MHC class II(+) staining was found amongst others in muscle cells surrounding the lesion. These results show that Sarcocystis antigens can induce an inflammatory response in bovine muscle having the characteristics of natural BEM.     

Elevated IgG antibody to Sarcocystis cruzi associated with eosinophilic myositis in cattle

Blood sera, skeletal muscle, and cardiac muscle from 24 bovine carcasses condemned for eosinophilic myositis by US Department of Agriculture meat inspection veterinarians were compared with similar specimens from 35 random carcasses passed for human consumption. Fluorescence values determined by using a fluorometric immunoassay system were used to measure the specific antibodies to Sarcocystis cruzi. The values were significantly elevated in carcasses condemned for eosinophilic myositis as compared to carcasses passed for human consumption. The elevated fluorescence values appeared to be more than coincidental, suggesting that S. cruzi may be a causative agent of eosinophilic myositis. Microscopic examination of affected muscle revealed lesions typical of eosinophilic myositis. Lesions were characterized by extensive multifocal areas of myofiber hyaline degeneration, necrosis with sarcoplasmic fragmentation, mineralization of occasional myofibers, and atrophy of fibers with varied stages of fibrosis. Inflammatory cell exudates were predominantly eosinophils, with some macrophages and lymphocytes, and extravasated erythrocytes within, and adjacent to, affected myofibers. Affected muscles contained more S. cruzi than unaffected muscle from passed carcasses. However, a distinct cause and effect relationship could not be determined between the parasite and the presence of eosinophilic myositis.     

An outbreak of sarcocystosis in a cattle herd.

In a cattle herd, 3 steers had anorexia and variable emaciation; 1 showed additional muscle stiffness, pyrexia, became recumbent and was killed in extremis. Gross changes in tissue specimens from this steer included grey-white foci in the skeletal muscle and a thickened, fibrous pleura. By histology interstitial pneumonia, myocarditis and necrotizing myositis were seen. There were wide-spread vascular lesions with endothelial damage, thrombosis and periarterial infiltrations. Sarcocystis-like schizonts were found in several organs, and different stages of thin-walled sarcocysts were seen in the myocardium. Examination of organs of 6 other steers in the same herd slaughtered 2 months later showed myocarditis, myositis, interstitial pneumonia and occasional vascular occlusions. There were a few schizonts in the spleen and lungs, and thin-walled sarcocysts were seen in the myocardium and skeletal muscle. It is concluded that development of vascular lesions probably represents an important step in the pathogenesis of sarcocystosis.     

Ultrastructural and transmission evidence of Sarcocystis cruzi associated with eosinophilic myositis in cattle.

Skeletal muscle, diaphragm, tongue, esophagus and heart of beef carcasses that were condemned for eosinophilic myositis and those that were unaffected were collected at an abattoir in Colorado and studied to determine the involvement of Sarcocystis spp. All affected carcasses contained similar granulomatous lesions with adjacent infiltrations of leukocytes. Intact or fragments of sarcocysts were found within 32 of 363 granulomas, and whole sarcocysts were present in nearby unaffected muscle cells. Light and electron microscopic examinations revealed that sarcocysts, affected or unaffected by cellular response in condemned carcasses, as well as those found in unaffected carcasses, were consistent with those of S. cruzi. Transmission experiments confirmed that S. cruzi were present in all carcasses, and that dogs, but not cats, were the definitive hosts. The results of pepsin-HCl digestion assays showed that unaffected carcasses that were approved for human consumption generally contained more infective parasites than carcasses that were condemned for eosinophilic myositis. This study provides evidence to support the suggestion that dogs, rather than cats, and unaffected rather than eosinophilic myositis-affected carcasses, have greater potential for contributing to the perpetuation of eosinophilic myositis in the cattle industry.     

Fatal hepatic sarcocystosis in a puppy with eosinophilia and eosinophilic peritoneal effusion

A 3-month-old male Golden Retriever puppy was evaluated for lethargy and fever of 2-days duration. Results of a CBC and biochemical profile revealed marked eosinophilia (6.3 X 10(3)/microL; reference interval 0.1-1.2 X 10(3)/microL), moderate thrombocytopenia, and increased activities of alanine aminotransferase, aspartate aminotransferase, and creatine kinase. Hepatomegaly and peritoneal effusion were found using abdominal ultrasound. Peritoneal fluid analysis revealed eosinophilic inflammation (23,000 nucleated cells/microL with 88% eosinophils). Despite supportive treatment the puppy's condition deteriorated rapidly; euthanasia was requested, and a necropsy performed. Microscopically, there was marked necrosuppurative and eosinophilic hepatitis with vasculitis. Numerous hepatocytes contained protozoal organisms suspected to be Toxoplasma gondii or Neospora caninum. However, serum was negative for both T gondii and N caninum antibodies; polymerase chain reaction assay on hepatic tissue was negative for both organisms; and immunohistochemical evaluation of hepatic tissue using serum raised against T gondii, N caninum, and Sarcocystis neurona also was negative. Schizont morphology suggested that merozoites replicated by endopolygeny, forming rosettes around a central residual body. Transmission electron microscopy revealed that merozoites lacked rhoptries. These findings were consistent with a diagnosis of Sarcocystis canis, an apicomplexan parasite with an unknown life cycle.     

An outbreak of sarcocystosis in dairy cattle

Sixteen of 32 Friesian calves, 8 to 10 weeks old, died over 4 weeks. The calves were housed in pens previously used by dogs. Clinical signs included anorexia, pale mucous membranes, rapid weight loss, coughing and palpably enlarged superficial lymph nodes. At necropsy, calves were emaciated and had generalised enlargement of lymph nodes, pale mottling of skeletal muscles, excess peritoneal, thoracic and pericardial fluid and subpleural and subepicardial haemorrhages. Histologically there was a lymphadenitis, myositis, myocarditis, glomerulonephritis, interstitial pneumonitis and encephalitis. Schizonts of a sporozoan parasite, presumably Sarcocystis cruzi were found in the endothelial cells of blood vessels in many organs.     

Immunodominant proteins of Sarcocystis cruzi bradyzoites isolated from cattle affected or nonaffected with eosinophilic myositis

Sarcocystis cruzi sarcocysts were isolated from eosinophilic myositis (EM)-affected and nonaffected bovine hearts. Isolates were ruptured and used to prepare a bradyzoite antigen extract from each heart. The nonaffected heart from one newborn calf contained no apparent sarcocysts when examined histologically and was used to prepare Sarcocystis-negative control antigen. Blood samples were taken from the heart approximately 20 minutes after slaughter. Serum was obtained and evaluated, using a radioimmunoassay to measure Sarcocystis-specific IgG and IgE titers. Sarcocystis cruzi extract from a heart without EM lesions was used for antigen in the radioimmunoassay. Sarcocystis-specific IgG titer ranged between 1:1,280 and 1:2,560 in EM-affected cattle and was 1:640 in non-affected cattle. Sarcocystis-specific IgE titer ranged between 1:640 and 1:1,280 in EM-affected and nonaffected cattle. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein (western) immunoblot analysis were used to compare antigen extracts and serum samples from EM-affected vs nonaffected cattle. Twenty protein bands, ranging from approximately 22 to 215 kD, were detected consistently on bradyzoite blots probed with anti-bovine IgG after incubation with serum samples. Seven of these bands, 37, 44, 53, 57, 94, 113, and 215 kD, were also detected consistently on bradyzoite blots probed with monoclonal anti-bovine IgE. One additional band, 61 kD, was detected consistently on bradyzoite blots probed for IgE, but was seldom recognized when probed for IgG. Sixteen protein bands were evident in silver-stained gels of S cruzi-negative, newborn calf antigen, but none were recognized by antisera on western blots.(ABSTRACT TRUNCATED AT 250 WORDS)     

Heavy sarcocystosis in the ocular musculature of cattle and buffaloes

A high prevalence of 71.5 per cent and 69.7 per cent of sarcocystosis was observed in the ocular musculature of cattle and buffaloes respectively, in Bihar, India. The concentration of cysts in the eye muscle was also usually heavy. Ocular musculature appears to be a preferred site for the development ofSarcocystis in these intermediate hosts, second only to the heart muscle. The species ofSarcocystis involved in the present study were morphologically indistinguishable fromS. cruzi in cattle andS. levinei in buffaloes. This appears to be the first report on the occurrence ofS. cruzi andS. levinei in ocular musculature.     

Eosinophilic myositis in a slaughtered Korean native cattle

Histopathological findings of eosinophilic myositis in the carcass of a slaughtered Korean native cow are presented. Lesions contained massive fibrous septae with vacuolar changes in some lesions, and the hypercontraction and rupturing of muscle bundles, with replacement by eosinophils. Necrosis and severe eosinophil infiltration were observed. Sarcoplasmic fragmentation and atrophy developed. Typical of granuloma, calcified myofibers were focally surrounded by macrophages and numerous inflammatory cells, and multinucleated giant cell formation was evident.     

The extent of the incidence of sarcocystosis in cattle and pig farms

The extensity of a chronic form of sarcocystosis was studied in certain age categories of cattle and pigs. The incidence of sarcocysts was investigated microscopically after 0.25% trypsin action in the muscles of bovine gullet and diaphragmal columns of pigs. Bovine fetuses and sucking calves did not have any sarcocysts. The first cases of positive findings were recorded in calves on milk diet (18.33%). The infestation rate of adult cattle is high in this country and reaches the level of 90%. The disease extensity in pigs is lower by an order and it did not exceed the level of 4%. There were found no significant differences (the mean 81.85%) in the infection rate in the cows coming from various regions of the CSR if the incidence of the disease was evaluated geographically. Larger percent differences were recorded between cattle and pig herds, mostly in the South Moravian Region, if evaluated by the districts and farms. The results of the investigation of 1273 head of cattle and 335 head of pigs coming from various farms were processed statistically. We tested the sarcocyst incidence in the muscular tissue in relation to the ways of housing and seasonal changes. Considerably lower rates of sarcocystosis infestation on the large cattle and pig farms were demonstrated. In the other case no relationship was proved. The samples taken in all year seasons could be evaluated in the same objective way. We discuss potential preventive measures of this parasitosis-zoonosis.     

Meningoencephalitis associated with disseminated sarcocystosis in a free-ranging moose (Alces alces) calf

A wild moose (Alces alces) calf was presented for necropsy due to severe neurologic signs. Histopathologic examination revealed multisystemic inflammation with intralesional mature and immature schizonts. Schizonts in the brain reacted positively to Sarcocystis spp. polyclonal antibodies. Gene sequencing of PCR-amplified DNA identified the species as Sarcocystis alceslatrans.     

Myocardial sarcocystosis in a grand eclectus parrot (Eclectus roratus) and a Moluccan cockatoo (Cacatua moluccensis)

Cardiac sarcocystosis is described in a grand eclectus parrot and a Moluccan cockatoo. Many cysts containing metrocytes were observed within cardiac muscle fibers on tissue sections stained with hematoxylin and eosin. Characteristic ultrastructural features of the cyst walls included the presence of villous projections containing microtubules. Compartmentalization of the cysts resulted from inward extensions of the cyst wall. The differential diagnosis of sarcocystosis, the life cycle of the parasite, and control measures are discussed.