Dengue Outbreak In Florida

Aug. 4, 2010, 8:41 a.m.

Aedes aegypti species of the mosquito, feasting on a human finger.  It is the mosquito responsible for transmitting Dengue fever, yellow  fever and more.
Jennifer Podis/Palm Beach Post

Aedes aegypti species of the mosquito, feasting on a human finger. It is the mosquito responsible for transmitting Dengue fever, yellow fever and more.

By Daphne Duret

Palm Beach Post Staff Writer

PORT ST. LUCIE — Among the shopping centers and plush housing developments in the Port St. Lucie neighborhood of Tradition, researchers are working to eradicate a worldwide scourge.

Scientists at the Vaccine and Gene Therapy Institute-Florida in Port St. Lucie and a related institution in Oregon have been researching dengue fever for years.

Now, as locally acquired cases of dengue are being reported in Florida for the first time in more than 75 years, VGTI's leaders say they have discovered promising leads they hope will eventually lead to drugs to prevent or treat the deadly mosquito-borne virus.

Dr. John Schatzle, manager of scientific affairs for VGTI Florida, said the recent cases in Key West have brought local attention to what his institute has already been researching vigorously.

"Think about it: People are going nuts over a few cases here in Florida, but 50 million people worldwide are getting this," Schatzle said. "It's one of those things that has such a global impact, even economically."

The World Health Organization estimates that between 50 million and 100 million people contract the virus each year, mostly in parts of the Caribbean, Latin America, Southeast Asia and Africa.

Dengue - which can cause high fever, pain behind the eyes, joint and bone pain, nausea and vomiting - is responsible for about 22,000 deaths worldwide. Foreign leaders have also attributed dengue outbreaks to economic losses from a lack of productivity by infected workers and a loss of tourism.

Dr. Jay Nelson, CEO and executive director of Oregon Health and Science University's Vaccine and Gene Therapy Institute, has studied dengue fever's effects for about five years in hopes of discovering a treatment or vaccine at the institute's headquarters in Beavertown, Ore.

Locally, Dr. Rafick-Pierre Sekaly has been examining the human immune system's responses to dengue fever compared with its response to yellow fever, a similar mosquito-transmitted virus for which an effective vaccine has existed since the mid-20th century.

But unlike with yellow fever and a few other viruses, contracting and surviving a bout with one of the four strains of dengue fever could cause a heightened immune response if a patient encounters another strain of the virus later. Schatzle says patients in that situation can experience stronger fevers, more organ damage, muscle aches, inflammation and other symptoms associated with the disease.

Therein lies one of the main challenges in finding a vaccine or treatment, Schatzle says.

And because there isn't an animal form of the virus that causes disease in lab creatures such as mice or primates, researchers haven't been able to research the effects of dengue through clinical trials with animals.

But Schatzle said advances in technology have allowed researchers at VGTI and elsewhere to get more information about dengue then ever before.

In the old days, scientists knew a treatment worked if "the patient lived or there was no violent reaction," Schatzle said. "We're much more sophisticated now."

VGTI was established in Oregon in March 2001 and announced its expansion to southwest Port. St. Lucie in January 2008. City officials lured the institute to Tradition with a $117.8 million state and local incentive package.

The offer included $60 million from the state's Innovation Incentive Fund - the same fund that enticed Torrey Pines, the Burnham Institute for Medical Research, the Max Planck Society and other research institutions to Florida in recent years.

VGTI studies the immune system's responses to three major health threats: cancer, aging and infectious diseases such as dengue.

Most notably, Nelson says researchers at the institute are working on what appears to be the most promising lead to date on an HIV vaccine. Clinical trials involving primates by VGTI in Oregon have had a 50 percent success rate, Nelson says, and the institute hopes to get backing soon to begin working on human clinical trials in both Oregon and Florida.

Nelson said the institute has several promising leads for a dengue vaccine, though he said he couldn't discuss the specifics because of patent issues. Making a potential vaccine available could take years.

VGTI in Port St. Lucie already has a partnership with Martin Memorial Hospital. Last year, the hospital agreed to find 270 volunteers to participate in a VGTI study aimed at answering questions about the common flu. Researchers have been looking at blood samples to figure out why infants and the elderly are most susceptible to severe flu and sometimes have trouble responding to vaccines.

Schatzle said the institute plans to continue working with Martin Memorial in the coming years, and the hospital is planning to build an 80-bed facility near the institute..

Nelson said that as the institute looked to expand from Oregon several years ago, the diversity and age range of Florida's population made the state an attractive location for a new research facility.

"If you look at viral diseases and bacterial diseases as well, the people who have the strongest reactions are the very young and the elderly," Nelson said. "Also, Florida is a port of entry for a number of diseases."

Schatzle says VGTI researchers are working with South Florida health officials involved in the recent Key West cases. They have made arrangements to get blood samples from those patients.

"As bad as having the disease there is, it is also really important for us to be there now," Nelson said.

Staff researcher Niels Heimeriks contributed to this story.

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