Schistosoma mansoni infection among prenatal attendees at a secondary-care hospital in central Sudan.

OBJECTIVE: To investigate the epidemiology of Schistosoma mansoni infection among pregnant women in a secondary-care hospital in Geizera state, Sudan. METHOD: Between August and September 2010, a cross-sectional study was conducted and questionnaires were administered to obtain basic sociodemographic and obstetric characteristics of pregnant women attending prenatal care at Araba Waeshreen Hospital. Stool samples were investigated for helminth infection via formol-ether concentration and Kato-Katz techniques. RESULTS: Of 292 pregnant women, 38 (13.0%) had S. mansoni infections. Hymenolepis nana and hookworm infections were present in 5 (1.7%) and 1 (0.3%) women, respectively. The intensity of the S. mansoni infection was light, moderate, and high in 13 (34.2%), 21 (55.3%), and 4 (10.5%) women, respectively. In multivariate analyses, parity, gestational age, and occupation were not associated with S. mansoni infection, unlike maternal age less than 20 years (odds ratio [OR] 9.8; 95% confidence interval [CI], 1.5-16.3; P=0.01) and no education (OR 6.2; 95% CI, 2.8-12.9; P<0.001). CONCLUSION: There was a high level of S. mansoni infection among pregnant women in the present setting, especially among younger women and those with no education. Control and preventive measures should be used in the area.

Laboratory Studies on the Prevalence and Cercarial Rhythms of Trematodes from Bulinus truncatus and Biomphalaria Pfeifferi Snails from Khartoum State, Sudan.

OBJECTIVES: (a) To determine the natural infection rate of Bulinus truncatus and Biomphalaria pfeifferi snails with trematodes' cercariae. (b) To determine the emergence and rhythmicity of cercariae. (c) To elucidate the high-risk time for man and other animals to acquire infection. METHODS: Snails were collected from Dawar El Mahadi Agricultural Scheme, Khartoum State, identified in the laboratory, kept at room temperature and fed on lettuce. The snails were screened weekly for six weeks for natural infection and infected snails were kept in the dark. The swimming patterns and resting position of the freshly emerged cercariae were studied using a stereomicroscope. The rhythmicity of the different types of cercariae was studied by screening three sets of 5 naturally infected snails under fluorescent light from 07.00 to 19.00 and similar sets from 19.00 to 07.00. RESULTS: Out of 1,257 screened Bulinus truncatus, 187 (14.9%) shed four types of cercariae. The highest prevalence of natural infection (9.5%) was by schistosome cercariae followed by amphistome (2.5%), xiphidiocercariae (2.4%) and lastly by avian cercariae (0.5%). However, out of 200 screened B. pfeifferi, 22 (11%) shed only xiphidiocercariae. The rhythmicity studies showed that the emergence of schistosome cercariae increased steadily from 07.00 to reach its peak at 11.00-13.00. The emergence rhythms of avian cercariae are similar to those of the schistosome, but with an early peak at 09.00-11.00. The xiphidiocercariae and amphistome cercariae started with high rate of emergence at 07.00. and decreased gradually to very low levels or complete disappearance, respectively, around sunset. CONCLUSION: Information on cercarial rhythmicity and chronobiological characteristics are thought to be useful in avoiding water contact during high-risk time of infection and may be helpful in the identification of closely related species and strains of cercariae.