Dengue Fever Outbreak Hits Hawaii

Hawaii has become the second U.S. state to have discovered an outbreak of locally acquired dengue fever. Florida has been combating its own local outbreak since September 2009. The Hawaii Department of Health reported on March 24 it had discovered two cases and suspected two more. Since then, KGMB reports four confirmed and 12 suspected cases. Florida saw 85 locally acquired cases in 2009 and 2010.

Dengue Fever and its far more serious variant, dengue hemorrhagic fever, are transmitted from patient to patient by the bite of a mosquito. The Asian Tiger mosquito (Aedes albopictus) and the Yellow Fever mosquito (Aedes aegypti) are the two primary vectors for the illness in the United States. Both mosquitoes are highly adapted to living around humans and are day feeders. The Asian Tiger mosquito has even evolved to a slower rate of beating its wings, which reduces the whine or hum typically noticed by people when mosquitoes are near.

The Hawaii outbreak is centered around Pearl City on the island of Oahu. The Florida outbreak has been confined to the Key West area with one case in Broward County and another in Miami-Dade.

Dengue is caused by one of four related viruses. There is a vaccine for one of the four. It is possible to catch each of the viruses since infection with one does not produce immunity for the others. It appears that initial infection, or the administration of the dengue vaccine, makes the patient significantly more susceptible to dengue hemorrhagic fever.

Many cases of dengue are seen in the continental United States each year. Nearly all are imported, caught outside the country and diagnosed in the U.S. Locally spread outbreaks are rare. Puerto Rico is in the midst of a dengue epidemic as is much of South and Central America.

The Centers for Disease Control and Prevention describe the symptoms of dengue as "high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding (e.g., nose or gums bleed, easy bruising)." Dengue hemorrhagic fever is described as "a fever that lasts from two to seven days, with general signs and symptoms consistent with dengue fever. When the fever declines, symptoms including persistent vomiting, severe abdominal pain, and difficulty breathing, may develop. This marks the beginning of a 24- to 48-hour period when the smallest blood vessels (capillaries) become excessively permeable ("leaky"), allowing the fluid component to escape from the blood vessels into the peritoneum (causing ascites) and pleural cavity (leading to pleural effusions). This may lead to failure of the circulatory system and shock, followed by death, if circulatory failure is not corrected."

The Asian Tiger mosquito is found throughout the southeastern part of the United States, as far north as central New Jersey. It has been found, in summer, in the New York city area. The Yellow Fever Mosquito is common throughout most of the United States south of a line from New York City through Chicago. Both types of mosquitoes are also carriers of other illnesses including yellow fever and Chikungunya. West Nile is another illness that the Asian Tiger mosquito can spread.

The CDC suggests a multipart strategy to avoid mosquito borne illnesses. Wear a mosquito repellent. Wear clothes that have been treated with repellent, and wear long sleeves, long legs and socks. Drain standing water from areas where mosquitoes can breed. Install screens for the windows and doors in your home.