Why is this risk only “in certain parts of the country”?
Arboviruses (like dengue, chikungunya, and Zika) can only establish
local transmission where a competent mosquito vector and a suitable climate are
both present. THis map shows climate-driven suitability for dengue transmission
by Aedes aegypti, as measured by the number of months in a typical year when conditions
support transmission (Messina et al., 2023). Based on this measure, significant risk for
these arboviruses seems likely to only be present in Miami, Houston, Dallas, and Atlanta
(though ris is not equal across these locations).
Malaria receptivity.
Malaria was eliminated from the United States in 1951, but the Anopheles
mosquitoes that carry malaria remain widespread. The map shows the
temperature suitability for Plasmodium vivax — the species
historically responsible for US malaria — from the Malaria Atlas Project (Gething
et al., 2011). Risk is highest in Houston and Miami, both in states where recent locally-acquired
cases occurred (Florida and Texas, 2023).
WC 2026 Threat Assessment