Prevalence and risk factors of schistosomiasis and hookworm infection in seasonal transmission settings in northern Côte d’Ivoire: A cross-sectional study

Abstract

Background Schistosomiasis and hookworm infection remain public health problems in large parts of sub-Saharan Africa. The epidemiology of schistosomiasis and hookworm was studied in seasonal transmission settings in the northern part of Côte d’Ivoire. Methodology In August 2018, a cross-sectional study was conducted. Urine and stool samples were collected from 742 individuals aged 6–96 years in 16 localities from four departments in northern Côte d’Ivoire. Urine samples were examined by a filtration method for quantification of Schistosoma haematobium eggs. Stool samples were subjected to duplicate Kato-Katz thick smears and eggs of Schistosoma mansoni and soil-transmitted helminths (STHs) were counted. Additionally, a questionnaire was administered to determine demographic characteristics and to identify risk factors of schistosomiasis and STHs. Malacologic surveys were carried out at water points that are contacted by humans and animals. Principal findings The prevalence of schistosomiasis was very low. Only two cases of S. mansoni were found (0.3%, 95% confidence interval [CI]: 0.1–1.0%). The distribution of S. haematobium was focal, with cases found only in two departments; Ferkessédougou (5.4%, 95% CI: 2.5–9.9%) and Ouangolodougou (2.7%, 95% CI: 0.9–6.3%). Hookworm was the only STH species observed with a prevalence of 1.5% (95% CI: 0.8–2.8%). A higher risk of S. haematobium infection was observed in males compared to females, but the difference was not statistically significant (2.3% versus 1.3%, odds ratio [OR]: 1.5, 95% CI: 0.8–2.7). Participants aged 16–20 years showed the highest prevalence of S. haematobium. A total of 111 human- and animal-water contact points were identified at 47 water sources. Three potential intermediate host snails of schistosomes were collected; namely, Bulinus forskalii (n = 761), Bulinus truncatus (n = 205), and Biomphalaria pfeifferi (n = 1). Yet, only one specimen of Bu. truncatus was found to be shedding schistosome cercariae. Conclusions/Significance This study confirms very low transmission of schistosomiasis and hookworm in northern Côte d’Ivoire. The establishment and rigorous implementation of integrated surveillance-response systems could lead to the elimination of schistosomiasis and hookworm in this part of Côte d’Ivoire.

Genetic characterization of schistosome species from cattle in Côte d’Ivoire

“…While we collected adult schistosomes and miracidia from sheep and goats as well as cercariae from snails, the prevalences in these hosts were very low; hence, we were not able to obtain sufficiently large samples to analyse schistosomes from the other hosts [ 11 ]. Our study was part of a One Health project [ 11 , 16 , 34 , 36 , 38 , 53 , 59 ]. Concurrent studies on human schistosomiasis and the role of pastoral systems show the benefits of a One Health approach by revealing epidemiological trends in livestock, which can inform prevention, control and elimination efforts.…”

“…This sampling strategy was undertaken to compare population genetic patterns revealed by sampling different host populations and parasite life stages. As described in previous papers [ 11 , 34 ], these sites were chosen because of the occurrence of human and animal schistosomiasis as well as the presence of small dams and water bodies frequented by both humans and livestock. As northern Côte d’Ivoire is the main livestock production area in the country, it is best suited for exploring the interactions between parasites and their host species, including humans, livestock and snails.…”

“…A walnut-size portion of faeces from each animal was washed, filtered and scraped with a wooden spatula through a drum filter (400-μm mesh size) with locally purchased bottled water. The filtrate was further filtered through a Pitchford filter [ 34 ]. The inner sieve mesh of the Pitchford filter was 300 μm and the outer sieve mesh was 30 μm, as described elsewhere [ 36 ].…”

Test-treat-track-test-treat (5T) approach for Schistosoma haematobium elimination on Pemba Island, Tanzania

“…Several countries, including Egypt and Morocco [ 5 – 8 ], and certain regions in sub-Saharan Africa, for example in Cameroon [ 9 ] and Côte d’Ivoire [ 10 ] have now reached very low levels of schistosomiasis and are approaching elimination. Large-scale MDA no longer seems justified in these areas as the majority of the population is not infected with Schistosoma spp [ 11 , 12 ].…”