Investigating transmission in a two-wave epidemic of chikungunya Fever, réunion island. | Investigating transmission in a two-wave epidemic of chikungunya Fever, réunion island.: Reproduction number of Chikungunya fever
2008
Boëlle, Pierre-Yves | Thomas, Guy | Vergu, Elisa | Renault, Philippe | Valleron, Alain-Jacques | Flahault, Antoine | Epidémiologie des maladies infectieuses et modélisation (ESIM) ; Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM) | INRA - Mathématiques et Informatique Appliquées (Unité MIAJ) ; Institut National de la Recherche Agronomique (INRA) | Cellule InterRégionale d'Epidémiologie Réunion Mayotte (CIRE) ; CIRE Réunion Mayotte
International audience
显示更多 [+] 显示较少 [-]英语. An epidemic of Chikungunya fever, a mosquito-borne viral disease, spectacularly swept through R?ion Island (population 780,000) in 2005-2006. There were 3000 cases in a first wave (March-June 2005) and more than 250,000 cases in a second (December 2005-April 2006). Adapting newly developed epidemiological tools to vector-borne diseases, we show that despite this massive difference in magnitude, the transmission potential as measured by the number of secondary cases per index case (or reproduction number), remained similar during the two consecutive waves. The best estimate for the initial reproduction number R(0) was 3.7, with a possible range from 2 to 11 depending on incubation duration and lifespan of the mosquito. We conclude that an increase in virulence between the two seasons was not necessary to explain the change in magnitude of the epidemics, and that the attack rate may be well over 50% in Chikungunya fever epidemics in the absence of intervention.
显示更多 [+] 显示较少 [-]