High prevalence and intensity of hookworm infection in the Dhofar Governorate, Oman

Prevalence of, and Factors Associated with Intestinal Parasites in Multinational Expatriate Workers in Al Ain City, United Arab Emirates: An Occupational Cross-Sectional Study

To estimate the prevalence of, and identify factors associated with intestinal parasites (IPs) in expatriate workers in the United Arab Emirates (UAE). All expatriate workers (N = 115) in a conveniently selected workplace in the industrial district of Al Ain city were invited to participate in a cross-sectional study. Consenting workers completed an interviewer-led questionnaire and self-collected stool samples. Stool samples were microscopically and molecularly screened for the presence of IPs. Univariate and multivariate analyses were conducted. Overall, 102 (88.7%) workers participated in the survey and 84.3% provided stool samples. Over three-quarters (79.4%) of workers were living in labour accommodation, 76.0% were sharing a bedroom with ≥ 4 workers, 80.2% were sharing a toilet with > 5 other people. Fifteen species of IPs were identified. Microscopically, 17.4% of the screened stool samples were positive for at least one parasite. Entamoeba species was the most common (8.1%) followed by Cryptosporidium species (3.5%). Thirty-six (41.8%) of the tested stool samples were positive for at least one parasite by molecular testing. The most prevalent parasite was Cryptosporidium species (16.3%) followed by Enterobius vermicularis (14.0%) and Ascaris lumbricoides (5.8%). Overall, 47.8% of the tested expatriate workers were positive for at least one IP, microscopically or molecularly. Educational attainment was negatively associated with being positive for at least one IP. IPs were very common amongst expatriate workers in Al Ain city. Efficacious and cost-effective public health interventions are required to reduce the burden of, and prevent the onward transmission of IPs in the UAE.

Emergence of infections with Schistosoma mansoni in the Dhofar Governorate, Oman

Infections with Schistosoma mansoni were identified in an area of Dhofar (Oman), where this parasite had been virtually absent during recent years and was reported only very sporadically before 1992. In the present survey, performed late in 2001, between 1 and 13% of children (n=519) were found to excrete eggs (one Kato-Katz-smear) in four schools, from four different villages, but no infections were detected in additional five schools (n=281). Infections were light (<72 eggs/g of faeces) in 19 of the 36 children found infected. Serologic examination of sera (n=511) was done by ELISA (based on soluble worm antigen) and immunofluorescence tests (IFT, based on cryostat sections of adult S. mansoni). The prevalence according to serological tests was between 3 and 43% in the four schools with infected children. Positive test results were taken to reflect active infections, since false positive reactions could largely be excluded. According to ultrasound (US) examinations performed on 96 individuals (children and adults) from the four villages, livers were normal in all except three cases of mild pathology, which could be assigned to schistosomiasis mansoni (pattern C, ages 32-40 years). All data suggest that transmission of S. mansoni has been re-introduced only recently in Dhofar and that this emergence of schistosomiasis is limited to at most a few foci.

Effective control of hookworm infection in school children from Dhofar, Sultanate of Oman: a four-year experience with albendazole mass chemotherapy

After 4 years of mass chemotherapy with a single annual dose of albendazole 400 mg, health education and promotion of environmental health, the prevalence of Necator americanus in Wilayat Tagah, Dhofar, Oman was reduced from 40 to 1.3% and from 6 to 0%, respectively, among rural and urban school children. Stool samples with egg load >1000 egg/gm were reduced from 28 to 0% after the first year of intervention and maintained as such in subsequent years.

Intestinal parasitic infections of urban and rural children on Pemba Island: implications for control

The intestinal parasites of the schoolchildren from one rural area and one urban area, both on Pemba Island, Zanzibar, Tanzania, were surveyed within the framework of the local Helminth Control Programme. Stool samples were examined for helminth eggs and protozoa by quantitative (Kato-Katz) and concentration (formalin-ether) techniques. The results indicate that intestinal helminthiases represent a significant public health problem in the study areas. All the subjects were found to be infected with helminths, most (> 97%) with more than one species. Hookworms and Trichuris appear to constitute the most serious challenges to the schoolchildren, both in terms of prevalence and intensity of infection. There were no significant differences between the results from the urban area and those from the rural area. The observations are important in the planning of control activities.