The state Health Department is investigating four cases of dengue fever that appear to have been contracted on Oahu.

Two cases are confirmed and two are suspected. The four adults fell ill late last month and have since recovered. The cases appear to be related and the patients were infected near their homes by mosquitos, Health Department investigators believe.

"The Department of Health immediately began precautionary measures by conducting additional testing, surveying and developing a mosquito control plan for the specific areas where these four individuals were likely infected," said Interim Health Director Loretta Fuddy. "We need the public’s help to clean up mosquito breeding areas throughout Oahu by emptying all standing water, and checking gutters and other areas that collect water."

The DOH sent out a medical alert to Oahu physicians earlier this week advising them to consider potential dengue infection in persons with compatible symptoms, request appropriate laboratory testing, and report all suspected cases to the DOH.

Dengue fever is a viral disease transmitted by the Aedes mosquito that occurs primarily in tropical and subtropical areas of the world. The illness is characterized by sudden onset of high fever, severe headaches, joint and muscle pain, nausea, vomiting and rash.  Younger children tend to have a milder illness than older children and adults and may show no symptoms.  Symptoms may last up to 10 days, but complete recovery can take two to four weeks. Treatment consists of rest, fluids, and medications to reduce fever, such as acetaminophen. Aspirin should not be used to treat a dengue patient.

Those with high fever in addition to any of the symptoms for dengue fever should see their doctor for evaluation.  Dengue is transmitted through mosquitoes which become infected by biting persons with fever and then pass on that infection by biting another person.  It is important that infected people with fever stay indoors to ensure they are not bitten by mosquitoes and indirectly pass on the infection.

Oahu residents and visitors are also advised to protect themselves against mosquito bites by applying repellant containing DEET (20-30%) or picaridin  to skin and clothing; repairing window and door screens to keep mosquitoes from entering indoors; and wearing darker clothing that covers and protects skin from biting mosquitoes.