Dengue Fever No Longer Just A Visitor To Florida Keys

FarmerJohn

Has No Life - Lives on TB
Dengue Fever No Longer Just A Visitor To Florida Keys
by MICHAELEEN DOUCLEFF
March 13, 2013

If you're heading down to the Florida Keys for spring break, pack bug spray and long-sleeve shirts.

After a 60-year hiatus, the mosquito-borne illness dengue fever has now officially re-established itself there.

People infected during a recent outbreak in Florida didn't catch the virus abroad but rather got a strain that's unique to Key West, virologists at the Centers for Disease Control and Prevention report Wednesday in the journal Emerging Infectious Disease.

The virus has been circulating around the Key West population for at least two years, the researchers say, and it has evolved its own genetic fingerprint, distinct from dengue in Central America and the Caribbean.

Also known as "breakbone fever," dengue causes pounding headache, high fever and such severe joint pain that you feel like your bones are — well, breaking.

There's no vaccine or cure. Although the disease is rarely fatal, doctors can't do much for it except treat the symptoms.


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Dengue fever was endemic in the U.S. before World War II, until the U.S. Army led aggressive mosquito-eradication campaigns to stop malaria among troops. Their efforts wiped out malaria in the U.S. and took dengue along with it.

But in the past decade or so, the virus and its primary transmitter, the Aedes aegypti mosquito, have been slowly making their way back into Florida.

In 2009, a woman from New York caught dengue while vacationing in Key West. It was the first case acquired in Florida in at least 40 years, and it triggered a larger investigation.

A survey by the CDC found that about 5 percent of the Key West community had been exposed to the virus, and at least 13 people got sick. In 2010, the cases grew to 63, and none of those infected had traveled to places outside the U.S. where the virus typically hangs out.

Such evidence suggested that dengue fever had set up long-term residency in Key West, instead of just popping in periodically with travelers. But to know for sure where a virus originates, you have to look at its genes.

So dengue specialist Jorge Munoz-Jordan and his team at the CDC examined the RNA sequences from 40 dengue strains around Florida.

The viruses from Key West all shared a similar genetic code, which was different from dengue strains found elsewhere in the world. In contrast, viruses from mainland Florida looked very similar to dengue in Central America and probably hopped a ride to the U.S. with vacationers.

The group of viruses in Key West "are practically identical to each other," Munoz-Jordan tells Shots. "They form a little family to themselves."

Munoz-Jordan isn't sure why dengue has returned to Florida. But the disease is definitely expanding its reach around the world.

In January, the World Health Organization reported that dengue cases had increased thirtyfold over the past 50 years, making breakbone fever the fastest spreading vector-borne viral disease in the world.

Of course, the threat of dengue in Florida is minor compared with other tropical regions. Since the 2010 outbreak, Florida has seen only a handful of dengue cases, Munoz-Jordan says, while nearby Puerto Rico recorded around 5,000 infections just in 2012.

The WHO estimates that nearly 100 million people are infected with dengue fever each year globally.

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http://www.npr.org/blogs/health/201...ever-no-longer-just-a-visitor-to-florida-keys
 

FarmerJohn

Has No Life - Lives on TB
Houston, We Have Dengue Fever

by THOMAS ANDREW GUSTAFSON
October 17, 2013 1:34 PM

Dengue fever is in Houston. And it turns out the mosquito-borne illness isn't exactly a stranger there.

Dengue has been roaming around the city since 2003, according to a study published Wednesday. "There was dengue circulating, and we had no idea that it was here because we just weren't looking," says the study's lead author Dr. Kristy Murray of the Baylor College of Medicine.

Like some other warm parts of the U.S., Texas experienced several dengue epidemics in the early 1900s. But intensive mosquito control helped curb the illness, except for occasional outbreaks along the border with Mexico.

The latest study shows dengue hasn't been pushed completely to the sidelines.

About 20 percent of people infected with dengue don't show any symptoms. The other 80 percent can experience high fever, severe headaches, rashes and vomiting. And in really bad cases, a variation called dengue hemorrhagic fever can make a person's capillaries leaky and bleed.

The study was published Wednesday in the journal Vector-Borne and Zoonotic Diseases.

The fever has gotten a foothold in the Florida Keys and moved further up the state earlier this year. But the type of fever in Florida is different from the type found in Houston, and that poses another problem.

If a person experiences one type and then suffers from another, the chances of having the hemorrhagic variety is much more likely, says Dr. Peter Hotez, dean of the National School of Tropical Medicine.

"If you recover from one type of dengue and then you have antibodies to the virus, having antibodies to one strain and then being infected with a second strain seems to work in synergy" against you, he tells Shots.

In the current study, Murray and her colleagues looked at samples of blood serum and spinal fluid collected between 2003 to 2005 from people with serious illnesses most likely brought on by infections.

Among 3,768 samples, the researchers found 47 that were positive for dengue fever. While that may not sound like very many, the samples came from the sickest people, which could mean there was an undercount of the fuller disease picture.

"It was pretty clear we had an outbreak that occurred in 2003 that would be classic as far as what we would think of as dengue transmission, and then we saw sustained transmission in 2004 and 2005," Murray tells Shots.

At first researchers thought dengue came back because travelers were carrying it from Central America where the illness is entrenched. But some samples positive for dengue came from people who never left the city. So it became clear those cases hadn't been imported.

There's no treatment or vaccine currently for dengue fever. So for now, Murray says the goal is to mitigate the spread of the fever as much as possible and to have doctors on board to check for the fever when dengue season comes back around next summer.

http://www.npr.org/blogs/health/2013/10/16/235628882/houston-we-have-dengue-fever
 

MtnGal

Has No Life - Lives on TB
Also known as "breakbone fever," dengue causes pounding headache, high fever and such severe joint pain that you feel like your bones are — well, breaking.

I don't think my body could take anymore joint pain - that would just do me in
 
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