Eight dogs were experimentally infected with Sarcocystis by oral inoculation of cardiac muscle from naturally infected cattle. The infected dogs commenced discharging of sporocysts in the feces after 10 to 12 days of inoculation, and continued until 20 and 35 days after inoculation. Three dogs were reinfected with cardiac muscle from the naturally infected cattle. Sporocysts reappeared in the feces on 12 to 13 days after reinfection. Sarcocystis sporocysts collected from the experimentally infected dogs were fed to each of the two 30-day-old Korean native calves. The infected calves remained clinically normal, except for the high fever (> or = 40 degrees C) and decreased hematocrit values on day 30 to 40 post inoculation. Muscular cysts of Sarcocystis were found from infected calves on day 40 post inoculation. Proliferative forms of Sarcocystis were also observed in the muscle of infected calves. These results suggest that the Sarcocystis cruzi found in Korean native cattle has a 2-host life cycle with dogs as the definitive host and Korean native calves as the intermediate host.
Animals ; Cattle ; Cattle Diseases/*parasitology ; Dog Diseases/*parasitology ; Dogs/*parasitology ; Host-Parasite Relations ; Korea ; *Life Cycle Stages ; Sarcocystis/*growth & development/isolation & purification ; Sarcocystosis/*parasitology/*veterinary

Sarcocystis sp. infection was investigated in 20 necropsied captive wild mammals and 20 birds in 2 petting zoos in Malaysia. The gross post-mortem lesions in mammals showed marbling of the liver with uniform congestion of the intestine, and for birds, there was atrophy of the sternal muscles with hemorrhage and edema of the lungs in 2 birds. Naked eye examination was used for detection of macroscopic sarcocysts, and muscle squash for microscopic type. Only microscopically visible cysts were detected in 8 animals and species identification was not possible. Histological examination of the sections of infected skeletal muscles showed more than 5 sarcocysts in each specimen. No leukocytic infiltration was seen in affected organs. The shape of the cysts was elongated or circular, and the mean size reached 254 x 24.5 micrometer and the thickness of the wall up to 2.5 micrometer. Two stages were recognized in the cysts, the peripheral metrocytes and large numbers of crescent shaped merozoites. Out of 40 animals examined, 3 mammals and 5 birds were positive (20%). The infection rate was 15% and 25% in mammals and birds, respectively. Regarding the organs, the infection rate was 50% in the skeletal muscles followed by tongue and heart (37.5%), diaphragm (25%), and esophagus (12.5%). Further ultrastructural studies are required to identify the species of Sarcocystis that infect captive wild animals and their possible role in zoonosis.
Animals ; Animals, Wild/*parasitology ; Animals, Zoo/*parasitology ; Cell Size ; Malaysia/epidemiology ; Muscle, Skeletal/pathology ; Sarcocystis/cytology/growth & development/*isolation & purification ; Sarcocystosis/epidemiology/parasitology/*veterinary