At the annual meeting of the American Society of Tropical Medicine and Hygiene on Thursday, scientists discussed research about the comparison of dengue fever found in Key West, Fla., and not in Tucson, Ariz.
Scientists said factors in the two cities are similar. Although mosquitoes that carry dengue are found in Arizona, the disease has not been confirmed in the city.
"Key West and Tucson share a lot of risk factors," Kacey Ernst, the infectious disease epidemiologist at the University of Arizona in Tucson, said. "Even in arid Tucson we have a large population of mosquitoes that can carry dengue, and people here spend a lot of time outdoors, but we have yet to see evidence of locally-acquired infections."
Preliminary findings from research that Ernst is conducting with Mary Haden from the National Center for Atmospheric Research were presented at the meeting.
Ernst and Haden surveyed residents of the two cities and discovered similarities. Residents of both cities said they spend at least an hour outside everyday, as well as use the air conditioner approximately 50 percent of the time.
"It is still a mystery as to why dengue infection has not shown up here," Ernst said. "When researchers looked at why dengue is not more common along the Texas side of the Mexico border, they cited factors limiting contact with mosquitoes, like people spending a lot of time in sealed, air conditioned buildings. Those issues are extremely important considerations, but we don't think they fully explain why Key West has dengue and Tucson doesn't."
Ernst said Tucson could be viewed as more vulnerable to the disease since it does not have the same extensive mosquito-control measures that are found in Key West. She said it is possible sporadic cases of dengue have occurred in Tucson that were undetected.
Ernst and Haden are also looking at Nogales, located in the Northern Mexico state of Sonora. They said factors there are ripe for dengue, including the mosquito that carries it, but no cases appear to be present.
Symptoms of dengue range from mild, flu-like symptoms to sever joint pain nicknamed "break-bone fever." Infections have the potential to progress to a fatal form of hemorrhagic fever. No drugs or vaccines are currently available.