Changes in the Transmission Dynamic of Chikungunya Virus in Southeastern Senegal

Abdourahmane Sow (1, 2, 3) , Birgit Nikolay (4, 5) , Oumar Faye (1) , Simon Cauchemez (4, 5) , Jorge Cano (6) , Mawlouth Diallo (7) , Ousmane Faye (1) , Bakary Sadio (1) , Oumar Ndiaye (1) , Scott C. Weaver (8) , Anta T. Dia (2) , Amadou Alpha Sall (1) , Denis Malvy (3)

1 Arbovirus et Virus de Fièvres Hémorragiques [Dakar, Sénégal]
2 UCAD - Université Cheikh Anta Diop de Dakar [Sénégal]
3 INSERM U1219 - UB - ISPED - Team MORPH3EUS
4 Modélisation mathématique des maladies infectieuses - Mathematical modelling of Infectious Diseases
5 Hub Bioinformatique et Biostatistique - Bioinformatics and Biostatistics HUB
6 LSHTM - London School of Hygiene and Tropical Medicine
7 UEM - Unité d'Entomologie Médicale [Dakar]
8 UTMB - The University of Texas Medical Branch

In Senegal, chikungunya virus (CHIKV) is maintained in a sylvatic cycle and causes sporadic cases or small outbreaks in rural areas. However, little is known about the influence of the environment on its transmission. To address the question, 120 villages were randomly selected in the Kedougou region of southeastern Senegal. In each selected village, 10 persons by randomly selected household were sampled and tested for specific anti-CHIKV IgG antibodies by ELISA. We investigated the association of CHIKV seroprevalence with environmental variables using logistic regression analysis and the spatial correlation of village seroprevalence based on semivariogram analysis. Fifty-four percent (51%–57%) of individuals sampled during the survey tested positive for CHIKV-specific IgG. CHIKV seroprevalence was significantly higher in populations living close to forested areas (Normalized Difference Vegetation Index (NDVI), Odds Ratio (OR) = 1.90 (1.42–2.57)), and was negatively associated with population density (OR = 0.76 (0.69–0.84)). In contrast, in gold mining sites where population density was >400 people per km2, seroprevalence peaked significantly among adults (46% (27%–67%)) compared to all other individuals (20% (12%–31%)). However, traditional gold mining activities significantly modify the transmission dynamic of CHIKV, leading to a potential increase of the risk of human exposition in the region.

Mots clés: Chikungunya; Senegal; environmental risk; gold mining; spatial autocorrelation

Domaines: Statistiques [math.ST]

Abdourahmane Sow, Birgit Nikolay, Oumar Faye, Simon Cauchemez, Jorge Cano, et al.. Changes in the Transmission Dynamic of Chikungunya Virus in Southeastern Senegal. Viruses, 2020, 12 (2), pp.196. ⟨10.3390/v12020196⟩. ⟨pasteur-03325914⟩