Sarcocystosis of animals and humans

Authors: Dubey, Jitender; CALERO-BERNAL, RAFAEL - US Department Of Agriculture (USDA); Rosenthal, Benjamin; SPEER, CLARENCE - Non ARS Employee; Fayer, Ronald

Submitted to: CRC Press
Publication Type: Book / Chapter
Publication Acceptance Date: 2/1/2015
Publication Date: 10/1/2015
Citation: Dubey, J.P., Calero-Bernal, R., Rosenthal, B.M., Speer, C., Fayer, R. 2015. Sarcocystosis of animals and humans. Boca Raton: CRC Press. 2:1-481 p.

Interpretive Summary: Species of Sarcocystosis, single-celled protozoan parasites in the Phylum Apicomplexa, are widespread in warm-blooded animals. They alternate between intermediate hosts, in which they encyst in muscles and tissues, and carnivores, in which the lifecycle is completed. Certain parasites in this large genus cause clinical infection in people and in livestock. Infections can retard growth in livestock, some are zoonotic, and there is a concern for food safety because humans ingesting uncooked infected meat suffer clinical illness. This book summarizes all that is known about the disease. ARS can take pride that a lot of the ground breaking research on this disease was done by researchers at Beltsville. This book will be useful to biologists, veterinarians, physicians, and researchers.

Technical Abstract: Species of Sarcocystosis, single-celled protozoan parasites in the Phylum Apicomplexa, are widespread in warm-blooded animals. Completion of the life cycle requires two host species: an intermediate (or prey) host and a definitive (or predator) host. Hosts can harbor more than one species of Sarcocystis. In intermediate hosts, whether normally involved in the life cycle or aberrantly involved, some species of Sarcocystis cause reduced weight gain, poor feed efficiency, anorexia, fever, anemia, muscle pain and weakness, reduced milk yield, abortion, neurologic impairment, and death. Such infections are of economic importance in intermediate hosts such as cattle, sheep, goats, and pigs. Disease has also been observed in avian species. Humans occasionally have been involved as aberrant intermediate hosts. In definitive hosts, some species of Sarcocystis can cause digestive disturbances including nausea, vomiting, and diarrhea. Humans serve as host for at least two such species. The underlying mechanisms giving rise to disease in both muscular and intestinal sarcocystosis are reviewed. Outbreaks of a mysterious disease with severe symptoms have been reported in vacationers returning from Malaysian islands. Symptoms included fever, myalgia, headache, and cough associated with elevated levels of enzymes indicative of muscle degeneration and inflammation. Muscle biopsies in a few patients revealed intra-muscular cysts containing zoites. In the absence of other etiologies, these infections have been identified as muscular sarcocystosis, presumably acquired from ingestion of water and food contaminated with Sarcocystis sporocysts of reptile origin. The evidence linking the infectious agent to Sarcocystis nesbitti of non human primates is herein reviewed. Methods of diagnosis and detection are discussed with regard to future needs. The status of chemo-prophylaxis, therapy, immunity, and vaccination is reviewed and future needs discussed.