The interaction between seasonality of mosquito and bird populations is critical in arbovirus transmission cycles. St. Louis encephalitis virus (SLEv) is endemic in south Florida and transmission in birds is observed most years, yet reaches levels sufficient to cause outbreaks in the human population only rarely. Models of the transmission cycle are being used to consider questions about factors important in transmission intensity and year to year variation. Previous models had suggested that an interaction in the timing of the peak in the mosquito population and reproduction in birds was important in generating outbreaks (high levels of transmission) in the bird population. A fine-scale sensitivity analysis was done to consider detailed effects of these timing factors on transmission and interactions between parameters in the model, with all other parameters fixed at most probable values. There were more outbreaks in the fine scale analysis than in previous sensitivity analyses with broad parameter ranges, indicating that the most probable parameter values are permissive for high levels of transmission. None of the timing variables strongly influenced the likelihood of outbreaks. Mosquito mortality rates did influence the likelihood of epidemics. Interactions between parameters were significant in the likelihood of outbreaks and in the size of outbreaks.
Species 1: Diptera Culicidae Culex nigripalpus
Keywords: St. Louis encephalitis, model
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