Improving early epidemiological assessment of emerging Aedes-transmitted epidemics using historical data

Julien Riou; Chiara Poletto; Pierre-Yves Boëlle

We introduce a hierarchical statistical model to analyze and extract information from historical data and obtain a priori distributions for required epidemiological parameters [27] . The method is [28] . Cases of ZIKV infection were dened as a rash with or without fever and at least two signs among conjunctivitis, arthralgia or edema". We obtained numbers of suspected cases by week for each island, extrapolated from the number of active sentinel sites (dataset D1). In the West Indies, local health authorities described the situation as epidemic when incidence was larger than 1 per 2,000 population per week (i.e. 200 cases in Guadeloupe and Martinique [29] , and 20 cases in Saint-Martin). Following this description, we dened the S(-tart) of the epidemic as the rst week above this threshold, the P (-eak) date when incidence was the highest, and the E(-nd) of the epidemic as the third consecutive week below the threshold (to ascertain the downwards trend). The time interval from S to E" corresponds to the period of high epidemic activity.