CD40LG and infection: Six of the flaviMIA positive sera were ZIKV IgM specific, two were cross-reactive between ZIKV and at least one other virus, while the remainder had IgM that specifically reacted to either DENV-2 or DENV-4 (both suggesting previous infection with these dengue serotypes) and two to YFV (consistent with previous vaccination with YFV associated with travel to South America).