Baseline and Impact of First-Year Intervention on Schistosoma haematobium Infection in Seasonal Transmission Foci in the Northern and Central Parts of Côte d'Ivoire

Nana R Diakité; Mamadou Ouattara; Fidèle K Bassa; Jean T Coulibaly; Yves-Nathan T Tian-Bi; Aboulaye Meïté; Jan Hattendorf; Jürg Utzinger; Eliézer K N'Goran

doi:10.3390/tropicalmed6010007

Baseline and Impact of First-Year Intervention on Schistosoma haematobium Infection in Seasonal Transmission Foci in the Northern and Central Parts of Côte d'Ivoire

Trop Med Infect Dis. 2021 Jan 8;6(1):7. doi: 10.3390/tropicalmed6010007.

Authors

Nana R Diakité^{1

2}, Mamadou Ouattara^{1

2}, Fidèle K Bassa^{1

2}, Jean T Coulibaly^{1

2

3

4}, Yves-Nathan T Tian-Bi¹, Aboulaye Meïté⁵, Jan Hattendorf^{3

4}, Jürg Utzinger^{3

4}, Eliézer K N'Goran^{1

2}

Affiliations

¹ Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan 22 BP 770, Ivory Coast.
² Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan 01 BP 1303, Ivory Coast.
³ Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland.
⁴ Faculty of Science, University of Basel, P.O. Box, CH-4003 Basel, Switzerland.
⁵ Programme National de Lutte contre les Maladies Tropicales Négligées à Chimiothérapie Préventive, Abidjan 06 BP 6394, Ivory Coast.

Abstract

In order to assess the impact of different control strategies against Schistosoma haematobium in seasonal transmission foci in Côte d'Ivoire, a three-year cluster randomized trial was implemented. The decrease in S. haematobium prevalence among children aged 9-12 years was the primary outcome. In the first step, an eligibility survey was conducted, subjecting 50 children aged 13-14 years to a single urine filtration. Sixty-four villages with a prevalence of S. haematobium of ≥4% were selected and randomly assigned to four intervention arms consisting of annual mass drug administration (MDA) before (arm 1) and after (arm 2) the peak transmission, biannual treatment with praziquantel before and after the peak transmission season (arm 3), and annual MDA before the peak transmission season, coupled with focal chemical snail control using molluscicides (arm 4). At baseline, we observed a prevalence of 24.8%, 10.1%, 13.9%, and 15.9% in study arms 1, 2, 3, and 4, respectively. One year after the first intervention, the prevalence decreased in all study arms by about two-thirds or more. The prevalence in arm 2 was lower than in arm 1 (3.5% vs. 8.1%), but the difference was not statistically significant (odds ratio (OR) = 0.42, 95% confidence interval (CI) = 0.10-1.80). After adjusting for baseline prevalence, arms 1 and 2 performed roughly similarly (adjusted odds ratio (aOR) = 1.03, 95% CI = 0.34-3.07). The prevalence in arms 3 and 4 (1.9% and 2.2%) were significantly lower compared to arm 1 in the unadjusted and the adjusted models (arm 3 vs. arm 1, OR = 0.22, 95% CI = 0.05-0.95, aOR = 0.19, 95% CI = 0.08-0.48; arm 4 vs. arm 1, OR = 0.26, 95% CI = 0.08-0.85, aOR = 0.23, 95% CI = 0.06-0.87). The initial intervention showed a significant impact on the prevalence of S. haematobium. It will be interesting to monitor the comparative impact of the different intervention arms and to determine whether the interruption of seasonal transmission of S. haematobium can be achieved in this epidemiological setting within three years.

Keywords: Côte d’Ivoire; Schistosoma haematobium; control strategies; intensity; prevalence; seasonal transmission.