The first two cases of human muscular sarcocystosis are reported from East Malaysia, in Sabalt and Sarawak respectively. Sarcocysts were seen iin biopsied specimen from the nasopharynx of both patients who had carcinoma of the nasopharynx. The measurements and appearances of the cysts and the zoites within the cysts were compared with the human cases of sarcocystosis previously reported in West Malaysia. Zoonotic and other aspects of these cases of East Malaysian sarcocystosis are discussed.
Established criteria for morphological typing of sarcocysts was applied to a large series of cases of human skeletal muscle sarcocystosis in Malaysia to determine the type of sarcocyst present. We also wanted to test the general usefulness of this classification and to determine if there are any new cyst types. Three-dimensional (3-D) reconstruction was done to see if the sarcocyst has a distinct 3-D morphology. A total of 66 sarcocysts from 21 cases of human muscle sarcocystosis obtained from a previous prevalence study were examined. Tissue sections (5 microns thick) were stained with haematoxylin and eosin and studied under the light microscope. For 3-D reconstruction, an image analyser was used to align and reconstruct the sarcocyst after microscopic images had been captured with a charge-coupled device (CCD) camera. All the cysts best fit into the type 4 category. This classification is generally useful, although cyst wall characteristics and zoite size appear to be the most reliable criteria for classification. The cyst width averaged 77 microns (range, 30-137.5 microns). Cyst walls were smooth, had no cytophaneres and were less than 1 micron thick. No secondary cyst wall or surrounding inflammation was evident. Numerous cyst merozoites with diameters averaging 1 micron filled the cyst lumen. Although septa were not apparent, in many cysts, zoites were arranged in a unique, curvilinear fashion that suggested their presence. 3-D reconstruction showed the sarcocyst to be a long, tortuous "cylinder" with no branching or other distinguishing feature.
Ultrastructural studies of sarcocysts obtained from Philippine water buffaloes revealed the presence of the commonly reported macroscopic species, Sarcocystis fusiformis, and the microscopic species Sarcocystis levinei (Dissanaike A, Kan S. Studies on Sarcocystis in Malaysia. I: Sarcocystis levinei n.sp. from the water buffalo Bubalus bubalis. Z Parasitenkd 1978;55:127-38), (Huong L, Dubey J, Uggla A. Redescription of Sarcocystis levinei Dissanaike and Kan, 1978 (Protozoa: Sarcocystidae) of the water buffalo (Bubalus bubalis). J Parasitol 1997;83:1148-52). The globular to oval microscopic cysts commonly observed in the muscles of the diaphragm and neck exhibit compartmentalized arrangement of zoites with septal partitions and measure 13-48 microns in diameter. The parasitophorous vacuolar membrane of sarcocyst bears minute and hair-like villar protrusions measuring 2.3-2.75 microns long emanating at certain distances from the primary cyst wall and lack microfilaments. Villar protrusions have expanded to dome-shaped base measuring 0.33-1.6 microns long by 0.22-1.0 micron wide, and intermediate and tapering distal segments bent approximately 90 degrees and run parallel to the cyst surface. The distal segments at some areas join to form conical tufts. The primary cyst wall bears numerous prominent undulations that are arranged in small clusters. The ground substance is 0.42-0.57 micron thick. This paper documents the first report of S. levinei in Philippine water buffaloes possessing the type 7 cyst wall.
Three cases of muscular sarcocystosis from West Malaysia are reported. The morphological features of the parasites from these three cases are similar to the eight cases previously reported from this country. A review of this total of eleven cases of muscular sarcocystosis showed that they were all incidental findings, where man acted as intermediate hosts of as yet unknown Sarcocystis spp. These cases of muscular sarcocystosis were probably zoonotic in origin and associated with close contact with definitive hosts (both domestic and wild animals) thus permitting the contamination of food and drink with sporocysts shed by these definitive hosts. These infections were probably acquired locally as most of the subjects were born in Malaysia and none had ever left the country to stay elsewhere. Eight of the eleven cases reported were associated with malignancies, especially of the tongue and nasopharynx.
Sarcocystosis, an unusual parasitic zoonotic disease, is caused by coccidian/ apicomplexan protozoa in humans and animals. The parasites usually develop in a heteroxenous predator-prey life-cycle involving final (carnivore) and intermediate (omnivore/herbivore) hosts. Besides the intestinal, non-invasive form of the disease in which humans and animals are the definitive hosts for certain Sarcocystis spp., the invasive form has come to recent attention. In the latter, humans and animals serve as intermediate host harbouring sarcocysts in their muscle tissue. Already in 1991 sarcocystosis was seen as a potential emerging food borne zoonosis in Malaysia, and in 2011 and 2012 the largest cluster of symptomatic human muscular sarcocystosis world-wide was reported from Tioman Island, Pahang state. In this review, we focus on invasive sarcocystosis in humans and animals in Malaysia, review the recorded cases and epidemiology, and present hypotheses.
A previously healthy 20-year-old man presented with prolonged intermittent low grade fever and cough for 6months. He had bilateral calf pain and lower limb weakness 2days prior to admission. Physical examination revealed multiple enlarged lymph nodes with hepatomegaly. There was bilateral calf tenderness with evidence of proximal myopathy. Full blood picture showed lymphocytosis with reactive lymphocytes and eosinophilia. Creatine kinase and lactate dehydrogenase were markedly elevated. Over 2 weeks of admission, patient was treated symptomatically until the muscle biopsy of right calf revealed eosinophilic myositis with muscular sarcocystosis. He was treated with albendazole and high-dose corticosteroids. Symptoms subsided on reviewed at 2weeks and the dose of corticosteroid was tapered down slowly over a month. Due to poor compliance, he was readmitted 1month later because of relapsed. High-dose corticosteroid was restarted and duration for albendazole was prolonged for 1month. His symptom finally resolved over 2weeks.
Sarcocystis nesbitti is a parasite responsible for a biphasic eosinophilic febrile myositis syndrome in two recent outbreaks in Malaysia. We demonstrate Th2 cytokine polarization in infected travelers, an overall cytokine production decrease in the early phase of the disease suggestive of initial immunosuppression, and elevated levels of proinflammatory and chemotactic cytokines in the later myositic phase.
Since 2011, about 100 travellers to the island of Tioman, Malaysia, have been diagnosed worldwide with suspected muscular sarcocystosis, a previously only sporadically observed parasitic disease. Source of infection and therapy remain unclear. Final diagnosis requires microscopic identification of cysts in muscle biopsies. The study objective was a systematic description of characteristic symptoms, laboratory investigations and treatment response.
Seven members of a 15-man U.S. military team that had operated in rural Malaysia developed an acute illness consisting of fever, myalgias, bronchospasm, fleeting pruritic rashes, transient lymphadenopathy, and subcutaneous nodules associated with eosinophilia, elevated erythrocyte sedimentation rate, and elevated levels of muscle creatinine kinase. Sarcocysts of an unidentified Sarcocystis species were found in skeletal muscle biopsies of the index case. Albendazole ameliorated symptoms in the index case; however, his symptoms persisted for more than 5 years. Symptoms in 5 other men were mild to moderate and self-limited, and 1 team member with laboratory abnormalities was asymptomatic. Of 8 team members tested for antibody to Sarcocystis, 6 were positive; of 4 with the eosinophilic myositis syndrome who were tested, all were positive. We attribute this outbreak of eosinophilic myositis to accidental tissue parasitism by Sarcocystis.
Sarcocystis booliati n.sp. is described from the moonrat Echinosorex gymnurus (Mammalia, Insectivora) from West Malaysia. The cysts are very thin-walled, not visible to the naked eye, and have no trabeculae or cytophaneres. They are found in skeletal but not heart muscle. The zoites are small, 5-8 by 2-3 mum with a mean of 6.5 by 2.2 mum, in dry fixed smears. Octoplasma garnhami n.gen. n.sp., a parasite of undetermined taxonomic status but belonging to the Coccidiasina, Apicomplexa, is also described from the same host. Only schizononts and pseudocysts with typically 8 zoites, have so far been seen in monocytes of the spleen and liver. The zoites are large, 15 by 3 mum and have a distinct nucleolus even in dry-fixed smears.