Risk factors for Schistosoma mansoni and hookworm in urban farming communities in western Côte d'Ivoire.

OBJECTIVES: To identify risk factors for Schistosoma mansoni and hookworm infections in urban farming communities, and to investigate small-scale spatial patterns of infection prevalence. METHODS: A cross-sectional survey was carried out in 113 farming households (586 individuals) and 21 non-farming households (130 individuals) from six agricultural zones in the town of Man, western Côte d'Ivoire. Heads of households were interviewed on common agricultural activities, land and water use, education attainment, socioeconomic status and sanitation facilities. Household members provided stool specimens that were processed by the Kato-Katz technique and a formol-ether concentration method and diagnosed for S. mansoni, hookworms and other soil-transmitted helminths and intestinal protozoa. Bayesian statistics were employed for spatial analyses. RESULTS: The prevalences of S. mansoni and hookworm in farming households were 51.4% and 24.7%, respectively. Risk factors for a S. mansoni infection comprised living in close proximity to the Kô River, water contact with irrigation wells and ponds and low education attainment. Living in zones of smallholder irrigated rice plots or large rice perimeters, using water from domestic wells, and low socioeconomic status were risk factors for a hookworm infection. We found significant spatial heterogeneity between agricultural zones, with the highest infection prevalences of S. mansoni and hookworm in the zone where there was a large rice perimeter. CONCLUSIONS: In this urban setting, both S. mansoni and hookworm infections were related to specific agricultural activities. Health education and active participation of urban farmers for the control of schistosomiasis and soil-transmitted helminthiasis is recommended.

Multiple parasite infections and their relationship to self-reported morbidity in a community of rural Côte d'Ivoire.

BACKGROUND: Concomitant parasitic infections are common in the developing world, yet most studies focus on a single parasite in a narrow age group. We investigated the extent of polyparasitism and parasite associations, and related these findings to self-reported morbidity. METHODS: Inhabitants of 75 randomly selected households from a single village in western Côte d'Ivoire provided multiple faecal specimens and a single finger prick blood sample. The Kato-Katz technique and a formol-ether concentration method were employed to screen faecal samples for Schistosoma mansoni, soil-transmitted helminths and intestinal protozoa. Giemsa-stained blood smears were analysed for malaria parasites. A questionnaire was administered for collection of demographic information and self-reported morbidity indicators. RESULTS: Complete parasitological data were obtained for 500/561 (89.1%) participants, similarly distributed among sex, with an age range from 5 days to 91 years. The prevalences of Plasmodium falciparum, hookworms, Entamoeba histolytica/E. dispar, and S. mansoni were 76.4%, 45.0%, 42.2%, and 39.8%, respectively. Three-quarters of the population harboured three or more parasites concurrently. Multivariate analysis revealed significant associations between several pairs of parasites. Some parasitic infections and the total number of parasites were significantly associated with self-reported morbidity indicators. CONCLUSIONS: Our data confirm that polyparasitism is very common in rural Côte d'Ivoire and that people have clear perceptions about the morbidity caused by some of these parasitic infections. Our findings can be used for the design and implementation of sound intervention strategies to mitigate morbidity and co-morbidity.

Efficacy and side effects of praziquantel against Schistosoma mansoni in a community of western Côte d'Ivoire.

Praziquantel is efficacious against the adult stages of all human schistosome parasites, and has become the drug of choice for morbidity control of schistosomiasis. There is concern that resistance to praziquantel might develop or already exists, and could be further facilitated through new control initiatives relying on large-scale administration of praziquantel. Therefore, monitoring praziquantel efficacy in different epidemiological settings is required. We assessed the efficacy and side effects of praziquantel against Schistosoma mansoni in a rural community of western Côte d'Ivoire. Three consecutive stool specimens from 545 children and adults were examined by the Kato-Katz technique, revealing an overall prevalence of 40.9%. S. mansoni-infected individuals were treated with a single oral dose of praziquantel at 40 mg/kg. The most frequent side effects were abdominal pain, dizziness and diarrhoea. The overall cure rate, assessed 6 weeks post-treatment, was 60.9%. Moderate or heavy infections were only cleared in half or one-third of the individuals, respectively. The total egg count reduction was 61.4%. Infection intensity pre-treatment was significantly associated with age, cure rate, reported diarrhoea and dizziness. Our findings call for additional studies that rigorously evaluate the efficacy of praziquantel against different schistosome species in entire communities, using similarly sensitive diagnostic approaches as employed here.