Waiting for chikungunya fever in Argentina: spatio-temporal risk maps

Chikungunya virus (CHIKV) transmission has been detected in America in 2013 andrecently reached south up to Bolivia, Brazil and Paraguay, bordering countries ofArgentina. The presence of the mosquito Aedes aegypti in half of thecountry together with the regional context drove us to make a rapid assessment oftransmission risk. Temperature thresholds for vector breeding and for virustransmission, together with adult activity from the literature, were mapped on amonthly basis to estimate risk. Transmission of chikungunya by Ae. aegyptiin the world was seen at monthly mean temperatures from 21-34ºC, with themajority occurring between 26-28ºC. In Argentina temperatures above 21ºC are observedsince September in the northeast, expanding south until January and retreating backto the northeast in April. The maximum area under risk encompasses more than half thecountry and around 32 million inhabitants. Vector adult activity was registered wheremonthly means temperatures exceeded 13ºC, in the northeast all over the year and inthe northern half from September-May. The models herein proposed show that conditionsfor transmission are already present. Considering the regional context and thehistoric inability to control dengue in the region, chikungunya fever illness seemsunavoidable.