Dengue

Several Texas laws (Tex. Health & Safety Code, Chapters 81, 84 and 87) require specific information regarding notifiable conditions be provided to the Texas Department of State Health Services (DSHS). Health care providers, hospitals, laboratories, schools, and others are required to report patients who are suspected of having a notifiable condition (25 Tex. Admin. Code §97.2).

Report dengue within one week. Reporting Forms

When reporting cases of Dengue, Dengue Hemorrhagic Fever, or Dengue Shock Syndrome, local and/or regional health agencies must complete a Mosquito-borne Disease Case Investigation Form.

Dengue Fever and Dengue Hemorrhagic Fever (Dengue Virus Infection)

Centers for Disease Control and Prevention, National Center for Infectious Diseases
CDC Dengue Fever Home Page; Travelers' Health Information on Dengue Fever 

• Dengue/dengue haemorrhagic fever
  World Health Organization
  Publications and Articles
• Pamphlet (PDF)
  Pamphlet with Frequently Asked Questions, presented in both English and Spanish, with tips.

Dengue is viral disease found primarily in urban and semi-urban areas of the tropics. It is transmitted by the Aedes mosquito, a domestic, day-biting mosquito that prefers to feed on humans. There are four types of dengue viruses, belonging to a family of viruses which include St Louis encephalitis virus, West Nile virus and yellow fever virus.

Infection with dengue viruses produces an array of clinical illness ranging from a nonspecific viral set of symptoms to a severe and fatal hemorrhagic (bleeding) disease. Three to 14 days after infection, people suddenly experience high fever, severe frontal headache, pain behind the eyeball, and joint and muscle pain; many experience nausea and vomit. A rash may appear 3-5 days after onset of fever and can spread from the torso to the arms, legs, and face. Most people recover completely within two weeks.

Others develop severe bleeding problems. This complication is called dengue hemorrhagic fever (DHF), and can be fatal if untreated.

People living in and traveling to an endemic area (an area where dengue occurs regularly) during an epidemic are at increased risk of being infected with the virus. Persons who were previously infected with one or more types of dengue virus, who are very young or old, or who have a weak immune system are thought to be at greater risk for developing dengue hemorrhagic fever.

Dengue has become more common and widespread in the past 40 years. As of 2002, dengue fever is endemic in most tropical countries of the South Pacific, Asia, the Caribbean, the Americas, and Africa. Up to 100 million cases occur every year, with over 2 billion people at risk of contracting it.

Most cases of dengue fever in the U.S. have been linked to the patients' travel to endemic areas. The mosquito that transmits dengue fever is found in Texas and across the southeastern U.S., so there is a potential risk for dengue transmission. Sporadic outbreaks have occurred in the Gulf coastal area and in extreme south Texas.

Dengue virus is transmitted to humans through the bites of infected female Aedes mosquitoes. Mosquitoes generally acquire the virus while feeding on the blood of an infected person. After virus incubation for 8-10 days, an infected mosquito is capable, while feeding, of transmitting the virus to humans for the rest of the mosquito's life.

Immunity to one of the four types of viruses does not protect a person from infection by another type.

Because Aedes mosquitoes usually bite during the day, be sure to use precautions throughout the day, especially during early morning hours before daybreak and in the late afternoon before dark, when they are most active.

• Use a mosquito repellent containing "DEET" (N, N-diethyl-meta-toluamide) on exposed skin
• Dress protectively by wearing long-sleeved shirts, long pants, socks, and shoes

• Remove, repair, or empty anything that collects rainwater: discarded plastic food containers, used automobile tires, flower pots, clogged roof gutters
• Check all screen doors and windows and repair as necessary
• Keep unscreened windows and doors closed
• Regularly change the water in outdoor birdbaths and pet and animal water containers
• Eliminate indoor mosquitoes with insecticides labeled for killing flying insects

Advise your physician of any illness with fever occurring within 2-3 weeks after leaving a tropical area. If diagnosed with dengue, avoid pain relievers that contain aspirin; use those with acetaminophen instead. Rest and drink plenty of fluids.

Dengue is diagnosed by a blood test. The physician will have to rule out a variety of illness with similar course, including early stages of malaria, mild yellow fever, influenza, viral hepatitis, typhoid, Rift Valley fever, and leptospirosis.

No vaccine is available for preventing or treating dengue infection. Treatment is supportive to ease symptoms. Dengue patients should be monitored for signs of DHF, especially hypotension (low blood pressure).

Dengue occurs in most areas of tropical Asia, the Pacific Islands, the Caribbean Islands, Mexico, Central and South America, and Africa. The risk of dengue infection for the international traveler is small unless an epidemic is in progress during the time of travel. While traveling, in addition to the personal precautions indicated, spend as much time as possible in air-conditioned buildings, hotels, or other closed environments that mosquitoes cannot easily enter.