300 patients (185 males, 115 females) were examined for intestinal parasites. About 40% of these patients was infected, 14% of which was heavily infected. The highest prevalence and intensity of infection with soil-transmitted helminths was found among Malays and Indians of different ages. Heavy infections with these helminths were also frequently encountered in young Chinese. Helminthic infections in patients over 60 years of age was significantly lower. There was no significant differences in the prevalence and degree of infection among males and females. The commonest helminth encountered was Trichuris trichiura, which usually occurred as trace single infections. Mixed infections with Ascaris and Trichuris, usually with the former as the predominating parasite, were also frequently observed.
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.
An active worm was seen in the right eye of a 62-year-old man in Malaysia. The worm was behind the lens and attached at one end to some vitreous fibers. It was tentatively identified as an immature Dirofilaria immitis. There appear to be only five previous authentic reports of filariae in the vitreous.
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.
The two species of Sarcocystis--S. levinei and S. fusiformis from the water buffalo, Bubalus bubalis, show some ultrastructural similarities in their cyst wall and zoites. The zoites of both species are of about the same size, banana-shaped and have 22 subpellicular microtubules, numerous micronemes, eight rhoptries, a micropore in the region of the micronemes, an elongated mitochondrion, and a nucleus. S. levinei has 200--300 micronemes and S. fusiformis has about 400. The sarcocysts of both species are trabeculated and their cyst walls have cytophaneres containing annulated fibrils and coarse, electron dense granules. The cytophaneres of S. levinei are sloping, with irregular, wavy outlines, whereas S. fusiformis has the cauliflower-type of cytophaneres. This difference in the appearance of the cytophaneres, together with the difference in size of the sarcocysts and their definitive hosts, further confirms that S. levinei and S. fusiformis are two distinct species in the water buffalo.
Three cases of schistosomiasis in 2 Filipinos and one Chinese in Sabah are reported. Diagnosis was based on incidental histological findings of Schistosoma japonicum-like ova in the liver and rectal biopsies. As these 3 patients are immigrants to Sabah, it is assumed that they are imported cases, and that Sabah has been free of the disease from 1970 to 1977.
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.
A total of 346 paediatric in-patients in the University Hospital in Kuala Lumpur was examined for infection with Enterobius vermicularis using two anal swabs taken on two consecutive days. 24% of these children. whose mean age was 6 years [range 2-14 years] were infected. The infection was more prevalent among children between the ages of 5-11 years. There is only a slight difference in the distribution of infection among Malay. Chinese and Indian children. There is no significant difference in the prevalance of infection between boys and girls.
A survey of 25,246 Malay, Chinese and Indian children and adults ranging from birth to over 60 years of age, of both sexes, from 4 types of communities with different conditions of environmental sanitation and socio-economic status revealed an overall incidence of infection with soil-transmitted helminths of 39.6 percent. The incidence of soil-transmitted helminthiasis was highest among rural rubber estates, followed closely by the urban slums or squatter areas and incidence of infection was low in the semi-rural new villages and the urban flats. The commonest helminth in all these areas was Trichuris trichiura and the commonest type of helminthic infection was mixed infections with Ascaris and Trichuris. Infection was most prevalent among Indians, followed closely by Malays. Chinese generally had lower incidences of infection. Soil-transmitted helminthiasis was also more prevalent among the younger age groups, starting from toddlers to 9 years and rising to a peak in the 10-19 years age group. Elderly people (60 years and above) from the squatter areas and some ofthe estates, new villages andflats also had a higher incidence of infection than the older adults (30-59 years). Malay and Indian children (under 15 years of age) having a higher overall incidence of injection also tended to have higher degrees of infection, as estimated by egg counts. There was no significant differences in the distribution of infection between males and females in most of the study areas. However, females in the squatter areas had a higher incidence of infection than males. Conversely, females in some of the flats (Sri Melati and Shaw Road) had a lower incidence of infection than males.