Is Dengue Fever on the Rise in the U.S.?
In the confirmed cases of dengue, 56% were second infections, 11% were the
person's first infection, and the remainder were indeterminable due to a lack
of necessary laboratory tests. Of the confirmed cases, 39% had hemorrhagic
manifestations. Also, of the confirmed cases, all had traveled from countries
within 10 days of the onset of illness: six patients had traveled from Haiti,
three from Puerto Rico, two from Columbia, two from Venezuela, one from
Barbados, one from Nicaragua, and one from Thailand.
Usually, the viremic period -- time that the virus circulates in the blood
stream -- is only four days, according to Gill. "One of the theories has
been that it would be very difficult to import the disease and have local
mosquitoes pick it up and start local transmission because the viremic period
was so short," she says. "The theory was that, by the time people
traveled back into the state, perhaps they would not be viremic anymore. But we
were able to isolate virus from individuals while they were in the state of
Florida, and that demonstrates that the risk of future transmission is
Is it possible that dengue fever will start to spread within Florida and to
other states? Yes, says Gill. "The last time dengue was ... [a problem] in
Florida was in the 1930s," she says. "There were big outbreaks in Tampa
and Miami. There hasn't been any local transmission documented since then.
[But,] certainly, individuals and mosquitoes that could be infected are coming
in and out of the state regularly. The incidence of dengue in the surrounding
countries is increasing dramatically."
Gill says that the incidence of dengue fever is probably a lot higher than
that detected in this study. The majority of dengue illnesses have flu-like
symptoms or no symptoms at all, so probably only the sickest people sought
medical care, she says.
What is the solution? Patients traveling to countries where dengue fever is
present need to protect themselves from mosquito bites by wearing protective
clothing and using mosquito repellent, according to Gill. They need to see a
physician if they become sick after returning home. When diagnoses of dengue
are confirmed, patients need to protect themselves from mosquito bites for the
period that they are sick, she says. "During that four-day period when they
may be viremic, they need to protect themselves from mosquitoes so the
mosquitoes don't bite them, pick up the virus, and possibly transmit it to
other people," she says.
- Dengue fever is a virus transmitted via mosquitoes that can cause intense
"bone-breaking" pain, and though recovery takes only a few days,
related fatigue can last a month or two.
- A new report shows that the incidence of dengue fever in Florida is higher
than previously suspected.
- When traveling to countries where dengue fever is a concern, one should
wear protective clothing and insect repellent.