Displaying publications 1 - 20 of 62 in total

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  1. Ultrastructure of Sarcocystis booliati Dissanaike and Poopalachelvam, 1975 from the moonrat, echinosorex gymnurus, in Malaysia
    Kan SP, Dissanaike AS
    Int J Parasitol, 1976 Aug;6(4):321-6.
    PMID: 821875
    Matched MeSH terms: Sarcocystis/ultrastructure*
  2. Ultrastructure of Sarcocystis sp. from the Malaysian house rat, Rattus rattus diardii
    Kan SP, Dissanaike AS
    Z Parasitenkd, 1977 Jul 29;52(3):219-27.
    PMID: 410181
    The ultrastructure of Sarcocystis sp. from the Malaysian house rat, Rattus rattus diardii, was studied with the electron microscope. The thin, uniformly-dense primary cyst wall had a row of vesicular invaginations which were also seen along the wall of the villi-like projections or cytophaneres. Within the villi were spherical bodies and hollow, curled structures. The ground substance beneath the primary cyst wall extended into the cyst as thin septa or trabeculae separating the tightly-packed zoites into compartments. Merozoites had a double-layered membrane, a conoid, 2 conoidal rings, 22 subpellicular microtubules, 6 rhoptries, 80-100 micronemes, scattered lipid droplets, and sac-like mitochrondrion, beside which was a Golgi apparatus. A micropore was occasionally seen at the anterior third of the zoite whereas the nucleus occupied the posterior third. Metrocytes were few in number and peripheral in location.
    Matched MeSH terms: Sarcocystis/ultrastructure*
  3. Light microscopic and three-dimensional morphology of the human muscular sarcocyst
    Wong KT, Clarke G, Pathmanathan R, Hamilton PW
    Parasitol Res, 1994;80(2):138-40.
    PMID: 8202453
    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.
    Matched MeSH terms: Sarcocystis/cytology*; Sarcocystis/isolation & purification
  4. Scanning electron microscopy of the human muscular sarcocyst
    Wong KT, Yusoff M
    Parasitol Res, 1995;81(4):359-60.
    PMID: 7624297
    Matched MeSH terms: Sarcocystis/isolation & purification; Sarcocystis/ultrastructure*
  5. Studies on Sarcocystis in Malaysia. I. Sarcocystis levinei n. sp. from the water buffalo Bubalus bubalis
    Dissanaike AS, Kan SP
    Z Parasitenkd, 1978 Apr 20;55(2):127-38.
    PMID: 417481
    Light and electron microscopic studies and feeding experiments have confirmed the presence of two species of Sarcocystis in the water buffalo Bubalus bubalis. One is the already known species with large macroscopic sarcocysts, Sarcocystis fusiformia (Railliet, 1897) Bernard and Bauche, 1912 and the other is S. levinei n. sp. which is being described in detail. The sarcocysts of S. levinei are 0.9 x 0.1 mm and the zoites in them 17.8 x 4.2 micrometer. Ultrastructurally, the primary cyst wall shows sloping villi with irregular wavy outlines. Within the villi are coarse granules and annulated fibrils. Trabeculae are present. The sexual stages of S. levinei occur in the subepithelial tissue of the small intestine of the dog and sporocysts shed by this definitive host are 15-16 by 10 micrometer.
    Matched MeSH terms: Sarcocystis/cytology*; Sarcocystis/ultrastructure
  6. Further stages of the "sporozoan" from the moon rat Echinosorex gymnurus, and its possible connection with Sarcocystis
    Dissanaike AS, Lim BL, Poopalachelvam M
    Southeast Asian J Trop Med Public Health, 1974 Sep;5(3):456-7.
    PMID: 4215149
    Matched MeSH terms: Sarcocystis/cytology; Sarcocystis/isolation & purification
  7. Antibodies to Sarcocystis in Malaysians
    Thomas V, Dissanaike AS
    Trans R Soc Trop Med Hyg, 1978;72(3):303-6.
    PMID: 97821
    Sera from 243 donors belonging to the four main ethnic groups in West Malaysia (Orang Asli, Malays, Chinese and Indians) were tested, using the indirect fluorescent antibody technique for the prevalence of antibodies to Sarcocystis. Almost 20% reacted positively at dilutions of 1:64 or higher and eight among the Orang Asli and Malays gave the highest titres of 1:256. Prevalence was highest in the Orang Asli and lowest in Chinese. 22 sera also reacted positively to Toxoplasma, whether due to polyparasitism or cross-reaction is, as yet, unknown.
    Matched MeSH terms: Sarcocystis/immunology*
  8. Ultrastructure of the human skeletal muscle sarcocyst
    Wong KT, Pathmanathan R
    J Parasitol, 1994 Apr;80(2):327-30.
    PMID: 8158479
    The ultrastructure of the human skeletal muscle sarcocyst found in Malaysia is reported. Sarcocyst-positive, formalin-fixed tongue tissues were postfixed in osmium tetroxide. The primary cyst wall consisted of a thin membrane supported by osmiophilic material that was interrupted regularly by vesicle-like invaginations. Although there were no cytophaneres, stubby protrusions of the primary wall were observed. These protrusions were accentuated by dense, curvilinear material externally. The primary wall was wavy over about half the cross section of the cyst. The granular ground substance underlying the primary wall occasionally contained hitherto undescribed coiled microtubular structures. Branching septa extended from the ground substance into the cyst, separating mature merozoites into compartments. A few peripheral metrocytes and many laminated myelin figure-like structures, probably degenerating merozoites, were found. Although the human muscular sarcocyst has the same basic ultrastructure as those found in other animals, the stubby protrusions and coiled microtubular structures in the ground substance have not been described previously in nonhuman animals.
    Matched MeSH terms: Sarcocystis/ultrastructure*
  9. Ultrastructure of sarcocysts from water buffalo in India
    Dubey JP, Speer CA, Shah HL
    Vet Parasitol, 1989 Nov;34(1-2):149-52.
    PMID: 2511659
    The ultrastructure of sarcocysts of macro- and microscopic species of Sarcocystis was compared from naturally infected water buffalo from India. Grossly visible sarcocysts had walls consisting of cauliflower-like villar protrusions, typical of S. fusiformis. The sarcocyst wall of the microscopic species of Sarcocystis was 6.4 microns thick and consisted of tightly packed conical villar protrusions that were 9.6 microns long and 3.7 microns wide at the base. At approximately 3 microns above the base, the distal two-thirds of the villar protrusion became conical shaped and was bent laterally at an angle of 45 degrees to the sarcocyst surface. The granular layer beneath the villar protrusions was 0.9 microns thick. In S. levinei the granular layer was 1.9 microns thick, the villar protrusions were narrow and it had a highly undulating primary cyst wall. Whether the microscopic S. levinei-like sarcocysts of Indian and Malaysian water buffalo are distinct species of Sarcocystis will require further investigation.
    Matched MeSH terms: Sarcocystis/ultrastructure*
  10. Ultrastructure of the cyst wall of Sarcocystis spp. from some rodents in Malaysia
    Kan SP
    Int J Parasitol, 1979 Oct;9(5):475-80.
    PMID: 118943
    Matched MeSH terms: Sarcocystis/ultrastructure*
  11. Finding Sarcocystis spp. on the Tioman Island: 28S rRNA gene next-generation sequencing reveals nine new Sarcocystis species
    Lee FCH
    J Water Health, 2019 Jun;17(3):416-427.
    PMID: 31095517 DOI: 10.2166/wh.2019.124
    The Tioman Island of Malaysia experienced acute muscular sarcocystosis outbreaks from 2011 to 2014. So far, a previous study based on the 18S rRNA gene sequencing has reported S. singaporensis, S. nesbitti and Sarcocystis sp. YLL-2013 in water samples acquired from the island, thus confirming the waterborne nature of this emerging parasitic disease. This study aimed to improve the detection methods for Sarcocystis, in order to have a clearer picture of the true diversity of Sarcocystis species in Tioman. A new primer set (28S R7F-28S R8 Deg R) was designed to amplify the 28S rRNA gene of Sarcocystis. Subsequently, Sarcocystidae was detected in 65.6% (21/32) of water samples and 28% (7/25) of soil samples acquired between 2014 and 2015 from Tioman. Next-generation sequencing (NGS) on 18 of the positive samples was then performed using amplicons generated from the same primer set. This yielded 53 potentially unique Sarcocystidae sequences (290 bp), of which nine of the most abundant, prevalent and unique sequences were named herein. In contrast, NGS of the 18S rRNA gene V9 hypervariable region of 10 selected samples detected only two Sarcocystis species (160 bp). S. mantioni was the most ubiquitous sequence found in this study.
    Matched MeSH terms: Sarcocystis*
  12. Revision of Sarcocystis orientalis Zaman and Colley, 1975
    Zaman V
    Southeast Asian J Trop Med Public Health, 1975 Dec;6(4):603.
    PMID: 818718
    Matched MeSH terms: Sarcocystis/classification*
  13. Fulltext Genetic assemblage of Sarcocystis spp. in Malaysian snakes
    Lau YL, Chang PY, Subramaniam V, Ng YH, Mahmud R, Ahmad AF, et al.
    Parasit Vectors, 2013 Sep 09;6(1):257.
    PMID: 24010903 DOI: 10.1186/1756-3305-6-257
    BACKGROUND: Sarcocystis species are protozoan parasites with a wide host range including snakes. Although there were several reports of Sarcocytis species in snakes, their distribution and prevalence are still not fully explored.

    METHODS: In this study, fecal specimens of several snake species in Malaysia were examined for the presence of Sarcocystis by PCR of 18S rDNA sequence. Microscopy examination of the fecal specimens for sporocysts was not carried as it was difficult to determine the species of the infecting Sarcocystis.

    RESULTS: Of the 28 snake fecal specimens, 7 were positive by PCR. BLASTn and phylogenetic analyses of the amplified 18S rDNA sequences revealed the snakes were infected with either S. nesbitti, S. singaporensis, S. zuoi or undefined Sarcocystis species.

    CONCLUSION: This study is the first to report Sarcocystis infection in a cobra, and S. nesbitti in a reticulated python.

    Matched MeSH terms: Sarcocystis/classification*; Sarcocystis/genetics*; Sarcocystis/isolation & purification
  14. Fulltext Sarcocystosis among wild captive and zoo animals in Malaysia
    Latif B, Vellayan S, Omar E, Abdullah S, Mat Desa N
    Korean J Parasitol, 2010 Sep;48(3):213-7.
    PMID: 20877499 DOI: 10.3347/kjp.2010.48.3.213
    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 µm and the thickness of the wall up to 2.5 µm. 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.
    Matched MeSH terms: Sarcocystis/cytology; Sarcocystis/growth & development; Sarcocystis/isolation & purification*
  15. Fulltext Examination of Sarcocystis spp. of giant snakes from Australia and Southeast Asia confirms presence of a known pathogen - Sarcocystis nesbitti
    Wassermann M, Raisch L, Lyons JA, Natusch DJD, Richter S, Wirth M, et al.
    PLoS One, 2017;12(11):e0187984.
    PMID: 29131856 DOI: 10.1371/journal.pone.0187984
    We examined Sarcocystis spp. in giant snakes from the Indo-Australian Archipelago and Australia using a combination of morphological (size of sporocyst) and molecular analyses. We amplified by PCR nuclear 18S rDNA from single sporocysts in order to detect mixed infections and unequivocally assign the retrieved sequences to the corresponding parasite stage. Sarcocystis infection was generally high across the study area, with 78 (68%) of 115 examined pythons being infected by one or more Sarcocystis spp. Among 18 randomly chosen, sporocyst-positive samples (11 from Southeast Asia, 7 from Northern Australia) the only Sarcocystis species detected in Southeast Asian snakes was S. singaporensis (in reticulated pythons), which was absent from all Australian samples. We distinguished three different Sarcocystis spp. in the Australian sample set; two were excreted by scrub pythons and one by the spotted python. The sequence of the latter is an undescribed species phylogenetically related to S. lacertae. Of the two Sarcocystis species found in scrub pythons, one showed an 18S rRNA gene sequence similar to S. zamani, which is described from Australia for the first time. The second sequence was identical/similar to that of S. nesbitti, a known human pathogen that was held responsible for outbreaks of disease among tourists in Malaysia. The potential presence of S. nesbitti in Australia challenges the current hypothesis of a snake-primate life cycle, and would have implications for human health in the region. Further molecular and biological characterizations are required to confirm species identity and determine whether or not the Australian isolate has the same zoonotic potential as its Malaysian counterpart. Finally, the absence of S. nesbitti in samples from reticulated pythons (which were reported to be definitive hosts), coupled with our phylogenetic analyses, suggest that alternative snake hosts may be responsible for transmitting this parasite in Malaysia.
    Matched MeSH terms: Sarcocystis/classification; Sarcocystis/genetics; Sarcocystis/isolation & purification*
  16. Fulltext Outbreak of human infection with Sarcocystis nesbitti, Malaysia, 2012
    Abubakar S, Teoh BT, Sam SS, Chang LY, Johari J, Hooi PS, et al.
    Emerg Infect Dis, 2013 Dec;19(12):1989-91.
    PMID: 24274071 DOI: 10.3201/eid1912.120530
    An outbreak of fever associated with myalgia and myositis occurred in 2012 among 89 of 92 college students and teachers who visited Pangkor Island, Malaysia. The Sarcocystis nesbitti 18S rRNA gene and sarcocysts were obtained from muscle tissues of 2 students. Our findings indicate emergence of S. nesbitti infections in humans in Malaysia.
    Matched MeSH terms: Sarcocystis/classification*; Sarcocystis/genetics; Sarcocystis/isolation & purification
  17. Fulltext Review of sarcocystosis in Malaysia
    Kan SP, Pathmanathan R
    Southeast Asian J Trop Med Public Health, 1991 Dec;22 Suppl:129-34.
    PMID: 1822870
    Sarcocystis is a tissue coccidian with an obligatory two-host life cycle. The sexual generations of gametogony and sporogony occur in the lamina propria of the small intestine of definitive hosts which shed infective sporocysts in their stools and present with intestinal sarcocystosis. Asexual multiplication occurs in the skeletal and cardiac muscles of intermediate hosts which harbor Sarcocystis cysts in their muscles and present with muscular sarcocystosis. In Malaysia, Sarcocystis cysts have been reported from many domestic and wild animals, including domestic and field rats, moonrats, bandicoots, slow loris, buffalo, and monkey, and man. The known definitive hosts for some species of Sarcocystis are the domestic cat, dog and the reticulated python. Human muscular sarcocystosis in Malaysia is a zoonotic infection acquired by contamination of food or drink with sporocysts shed by definitive hosts. The cysts reported in human muscle resembled those seen in the moonrat, Echinosorex gymnurus, and the long-tailed monkey, Macaca fascicularis. While human intestinal sarcocystosis has not been reported in Malaysia so far, it can be assumed that such cases may not be infrequent in view of the occurrence of Sarcocystis cysts in meat animals, such as buffalo. The overall seroprevalence of 19.8% reported among the main racial groups in Malaysia indicates that sarcocystosis (both the intestinal and muscular forms) may be emerging as a significant food-borne zoonotic infection in the country.
    Matched MeSH terms: Sarcocystis/classification; Sarcocystis/immunology; Sarcocystis/physiology*
  18. Third case of Sarcocystis from man in Malaysia
    Prathap K, Dissanaike AS
    Southeast Asian J Trop Med Public Health, 1976 Sep;7(3):489.
    PMID: 828977
    Matched MeSH terms: Sarcocystis
  19. Molecular evidence of Sarcocystis nesbitti in water samples of Tioman Island, Malaysia
    Shahari S, Tengku-Idris TI, Fong MY, Lau YL
    Parasit Vectors, 2016 11 23;9(1):598.
    PMID: 27881179
    BACKGROUND: Sarcocystis are intracellular protozoan parasites that are characterised by their ability to invade muscle tissue and form intramuscular sarcocysts. A muscular sarcocystosis outbreak was reported by travellers returning from Tioman Island in 2011 and 2012 where Sarcocystis nesbitti was identified as the main cause. The source of the S. nesbitti that was involved has remained elusive, although water is hypothesised to be the main cause of transmission. A surveillance study was therefore undertaken in the northern regions of Tioman Island to identify the source of S. nesbitti by screening rivers, water tanks, wells and seawater.

    METHODS: Water samples were collected from rivers, water tanks, wells and seawater on Tioman Island over the course of April to October 2015. Water samples were indirectly screened for Sarcocystis species by obtaining sediment from respective water sources. PCR amplification of the 18S rRNA gene region was conducted to identify positive samples. Microscopy was used in an attempt to reappraise PCR results, but no sporocysts were detected in any of the samples.

    RESULTS: A total of 157 water samples were obtained and 19 were positive for various Sarcocystis species. Through BLASTn and phylogenetic analysis, these species were found to be S. singaporensis, S. nesbitti, Sarcocystis sp. YLL-2013 and one unidentified Sarcocystis species.

    CONCLUSIONS: This is the first positive finding of S. nesbitti in water samples on Tioman Island, which was found in a water tank and in river water samples. This finding supports the hypothesis that water was a potential medium for the transmission of S. nesbitti during the outbreak. This will potentially identify areas in which preventive measures can be taken to prevent future outbreaks.

    Matched MeSH terms: Sarcocystis/classification; Sarcocystis/cytology; Sarcocystis/genetics; Sarcocystis/isolation & purification*
  20. Light and electron microstructure of a Sarcocystis sp. from the Malaysian long-tailed monkey, Macaca fascicularis
    Kan SP, Prathap K, Dissanaike AS
    Am J Trop Med Hyg, 1979 Jul;28(4):634-42.
    PMID: 111569
    The ultrastructure of the cyst wall and zoites of a species of Sarcocystis from the skeletal muscles of a naturally-infected Malaysian long-tailed monkey, Macaca fascicularis, is described in detail. The wavy, electron-dense primary cyst wall is thin (55 nm) and invaginated. Cytophaneres are absent. The ground substance contains electron-dense granules and bundles of parallel, fibrillar elements in some areas. Thin trabeculae are present. The zoites measure 1.2 X 4.7 microns and have an interior conoid, 22 subpellicular microtubules, 50-60 micronemes, 4-6 rhoptries, and a posteriorly situated nucleus. Some ultrastructural aspects of the cyst wall and the zoites of this parasite resemble those of Sarcocystis species of the moonrat, rhesus monkey, tamarin, and baboon. The light microscopic appearance of this species from M. fascicularis also bears some resemblance to that of parasites from the four cases of human Sarcocystis reported in Malaysia. The cyst in all these human cases were thin-walled, with no cytophaners. Although the final hosts of these species of Sarcocystis are not known, it is quite possible that man, monkeys, and perhaps the moonrat (an insectivore) may serve as common intermediate hosts for one or several species of Sarcocystis.
    Matched MeSH terms: Sarcocystis/ultrastructure*
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