Rift valley fever in humans and animals in mayotte, an endemic situation?

Tinne Lernout (1) , Eric Cardinale (2, 3) , Maël Jego (3, 4) , Philippe Desprès (5, 6) , Louis Collet (7) , Betty Zumbo (8) , Emmanuel Tillard (9) , Sébastien Girard (10) , Laurent Filleul (11)

1 Regional office (Cire) of the French Institute for Public Health Surveillance (Institut de veille sanitaire)
2 CRVOI - Centre de Recherche et de Veille sur les Maladies Émergentes dans l'Océan Indien
3 UMR CMAEE - Contrôle des maladies animales exotiques et émergentes
4 LBBE - Laboratoire de Biométrie et Biologie Evolutive - UMR 5558
5 Interactions Moléculaires Flavivirus-Hôtes
6 CC-OMS - Centre collaborateur de l'OMS Arbovirus et Fièvres Hémorragiques virales - Stratégies antivirales
7 CHM - Laboratory of the Hospital Centre of Mayotte
8 Service de lutte anti-vectorielle
9 Cirad - Centre de Coopération Internationale en Recherche Agronomique pour le Développement
10 LASMEA - Laboratoire des sciences et matériaux pour l'électronique et d'automatique
11 Cellule Interrégionale d'Epidémiologie (CIRE)

Retrospective studies and surveillance on humans and animals revealed that Rift Valley Fever virus (RVFV) has been circulating on Mayotte for at least several years. A study was conducted in 2011 to estimate the seroprevalence of RVF in humans and in animals and to identify associated risk factors. Using a multistage cluster sampling method, 1420 individuals were enrolled in the human study, including 337 children aged 5 to 14 years. For the animal study, 198 seronegative ruminants from 33 randomly selected sentinel ruminant herds were followed up for more than one year. In both studies, information on environment and risk factors was collected through a standardized questionnaire. The overall weighted seroprevalence of RVFV antibodies in the general population aged ≥5 years was 3.5% (95% CI 2.6-4.8). The overall seroprevalence of RVFV antibodies in the ruminant population was 25.3% (95% CI 19.8-32.2). Age (≥15), gender (men), place of birth on the Comoros, living in Mayotte since less than 5 years, low educational level, farming and living close to a water source were significantly associated with RVFV seropositivity in humans. Major risk factors for RFV infection in animals were the proximity of the farm to a water point, previous two-month rainfall and absence of abortions disposal. Although resulting in few clinical cases in humans and in animals, RVFV has been circulating actively on the island of Mayotte, in a context of regular import of the virus from nearby countries through illegal animal movements, the presence of susceptible animals and a favorable environment for mosquito vectors to maintain virus transmission locally. Humans and animals share the same ways of RVFV transmission, with mosquitoes playing an important role. The studies emphasize the need for a one health approach in which humans and animals within their ecosystems are included.

Domaines: Sciences du Vivant [q-bio]

Tinne Lernout, Eric Cardinale, Maël Jego, Philippe Desprès, Louis Collet, et al.. Rift valley fever in humans and animals in mayotte, an endemic situation?. PLoS ONE, 2013, 8 (9), pp.e74192. ⟨10.1371/journal.pone.0074192⟩. ⟨hal-00972561⟩