Histological identification of muscular sarcocystis: A report of two cases.

Sarcocystis is an apicomplexan protozoan belonging to same phylum as toxoplasma. The parasite encysts inside striated muscles of its intermediate host. Humans are accidental host infected by eating food or water contaminated with oocysts or sporocysts of an infected definitive host. The infection is increasing in Southeast Asia and may be overlooked in histological sections if one is not aware of the histomorphological features. The size and shape of the bradyzoites and the appearance of the cyst wall are the reliable features to distinguish this parasite from other parasites of the same phylum. The incidence of human infection is rising in Southeast Asia and histopathology is an important method for the diagnosis of muscular infection. It is important to recognize the histomorphology of this parasite and its differentiation from similar parasites.

Prevalence, localization and morphology of sarcocystis species [apicomplexa: Sarcocystidae] infecting horses [Equus caballus] and donkeys [Equus Asnis] in Egypt

Musculature samples of oesophagus, heart, diaphragm, tongue, masseter and skeletal muscles from each of 52 horses and 130 donkeys were microscopically examined by both, compressorium and trypsin digestion techniques for detection of Sarcocystis infection. The infection rate reached 88.5% in horses and 91.5% in donkeys. The sarcocysts were detected in all examined samples with the highest rate in oesophagus [100%]. The morphology and size of the detected sarcocysts, metrocytes and bradyzoites in both, horses and donkeys were found to be similar. The cyst wall was thick [> 2 microm] and appeared striated. Experimentally infected dogs with horse or donkey meat excreted sporocysts measuring 12.2 - 14.6 X 9.0 - 10.7 microm and 12.0 - 14.9 X 8.3 - 10.7 microm. respectively. The prepatent period was 10 - 14 days. It was concluded that Sarcocystis infecting both, horses and donkeys in Egypt could belong to the same species [Sarcocystis bertrami]

Sarcocystis infection in an Orang Asli: the second human case from Malaysia.

The second case of Sarcocystis infection in man is reported from an aborigine girl. It was an incidental finding at autopsy and two cysts were seen in the muscle of the oropharyngeal region. The cysts and zoites were similar to those in the previous case reported from Malaysia.