Determining the prevalence of intestinal parasites in three Orang Asli (Aborigines) communities in Perak, Malaysia.

This study was conducted to determine the prevalence of intestinal parasites among children and adult Orang Aslis (Aborigines) from different locations in Perak. Faecal samples were collected and analyzed using the direct smear and formal ether sedimentation technique. Some of the faecal samples were stained using the Modified Acid fast stain for Cryptosporidium. Nail clippings of the respondents and the soil around their habitat were also analyzed. Of the 77 stool samples examined, 39 (50.6%) were positive for at least one intestinal parasite. The most common parasite detected was Trichuris trichiura (39.0%) followed by Ascaris lumbricoides (26.9%), Entamoeba coli (5.2%), Giardia lamblia (5.2%), Blastocystis hominis (3.9%), hookworm (3.9%), Entamoeba histolytica (1.3%), Iodamoeba butschlii (1.3%) and Cryptosporidium sp. (1.3%) respectively. Some respondents had single parasites (24.7%), some with two parasites (18.2%). Some with three parasites (6.5%) and one had four parasites species (1.3%). The parasites were slightly more common in females (54.7%) than males ((41.7%). The parasites were more common in the 13-20 year age group (90.9%) followed by 1-12 years (69.6%), 21-40 year age group (34.8%) and least in the 41-60 year age group (27.8%). Nail examinations of the respondents did not show any evidence of parasites. One had a mite, three had pollen grains and one had yeast cells isolated from the finger nails. Soil samples taken around their houses showed only one sample with a nematode ova and one with oocyst which was of a non human origin.

Intestinal parasitic infestation among different population groups of Andaman and Nicobar islands.

A survey was carried out among the rural and urban settlers and two tribal groups viz. Nicobarese and Onges, of Andaman and Nicobar islands. The survey covered preschool school aged children and adults. Out of the total 1,384 stool samples examined, 652 (47.1%) showed ova or cysts of one or more intestinal parasites. Among the preschool children, Nicobarese showed the highest overall prevalence rate (80.5%) followed by urban (46.7%) and rural (38.6%) preschool children. Ascaris lumbricoides was the commonest form of parasite encountered in all the groups of preschool children, followed by Trichuris trichura. While ascariasis and trichuriasis were more common among the urban children than in rural children, giardiasis was more common among the rural preschool children. The school age children among rural settlers showed an overall prevalence rate of 61.1% which was significantly higher than that among the rural preschool children. Among the school age children also, ascariasis was the commonest form of parasitosis followed by trichuriasis. The Nicobarese and Onge adults showed significantly higher overall prevalence rates (72.2%) and 71.1% vs 48.6%) compared to rural adults. In all the groups studied ascariasis was the commonest form of parasitosis except in Onges among whom trichuriasis and giardiasis were more common than ascariasis. Change in prevalence rates over age was studied among the rural settlers. While ascariasis and trichuriasis showed peak prevalence rates in school age children prevalence of giardiasis declined with increase in age from a peak in the preschool age group and prevalence rates of hook worm infestation continued increasing beyond school age.

Helminthiasis and cultural change in the Peruvian rainforest.

The objective of this study was to identify the impact of cultural and ecological change on intestinal helminth infections in traditional indigenous communities in the Peruvian rainforest and to identify the ways of transmission of helminth eggs. A remote indigenous settlement was compared with a more developed mestizo town. Stool specimens as well as soil, dust, air and water were examined for Ascaris and Trichuris eggs. A significantly lower infection intensity of Ascaris and Trichuris could be demonstrated for the traditional Indian community. Here the hygienic conditions were found to be better than in the town. The mestizo teacher and his family, who had come from the town to the Indian settlement, showed poorer hygienic standards and higher levels of Ascaris and Trichuris egg excretion than the Indian dwellers. The distribution of Ascaris and Trichuris eggs in the soil, house dust and in the air suggests that the contaminated dust from defaecation sites was distributed through the whole community by feet, animals (chickens) and wind. It was observed that many traditional habits that contributed to the good hygiene of the native population were being abandoned in the process of cultural change.

Modes of transmission for Ascaris lumbricoides and Trichuris trichiura among Chinese children in Macao City.

To obtain more information on the transmission of Ascaris lumbricoides and Trichuris trichiura in Macao City, 308 Chinese children were surveyed. The infection rates of A. lumbricoides and T. trichiura were 14.9 and 6.8%, respectively. There was no association between the infections. A. lumbricoides infection was associated with age and T. trichiura with new immigrants from China. No association was found between the infections and family socio-economic factors. The results suggest that the modes of transmission for A. lumbricoides and T. trichiura may be different in highly urbanized areas.