Dengue Fever,an Infectious Tropical Disease Carried by Mosquitos,has

Dengue fever,an infectious tropical disease carried by mosquitos,has

A) spread previously unaffected areas due to changes in climatic conditions.
B) never been reported in the U.S.,but scientists fear it may arrive due to expansion of Aedes aegypti mosquitoes.
C) shifted equatorward due to desertification in the subtropics.
D) been nearly wiped out because of climate change related shifts in subtropical high pressure cells.