So, what’s dengue fever, and why should you care? It’s a viral infection spread by infected mosquitos, and it is becoming more common.
The dengue virus can be asymptomatic or mild to severe. Only one in four people infected will develop symptoms. About twenty percent of symptomatic cases will end up being severe.
However, severe dengue can even be fatal. Infants, older adults (age 65 or older), pregnant women, and people with certain chronic illnesses are most susceptible to developing a severe case.
Severe dengue usually has one or more warning signs: abdominal pain or tenderness, persistent vomiting, fluid accumulating in the abdomen or chest, bleeding from mucosal surfaces such as the mouth or nose, lethargy, or restlessness.
A physician may detect an enlarged liver in these patients. Certain abnormal lab tests may also be found (elevated number of red blood cells, low platelets and/or low white blood cells).
Patients with severe dengue should be treated with careful fluid replacement and supportive care. Children in parts of the world with high numbers of cases, e.g., Puerto Rico, can be given a vaccine early in the course of the illness.
Fortunately, 80% of people who are symptomatic will have a mild case. They usually have a fever and non-specific findings such as nausea, vomiting, rash, muscle aching, joint or bone pain, pain behind the eyes, and/or headache. They usually have a low blood white cell count. There are specific blood tests to make the diagnosis.
The incubation period is 3 to 10 days after a mosquito bite infected with the dengue virus. There are no approved anti-viral medications to treat dengue fever. Symptomatic treatment and maintaining good hydration are indicated.
The incidence of dengue fever is increasing dramatically worldwide. As areas experience higher temperatures, the mosquitos expand their range.
So far, the U.S. has had more infections than in the past, even a year ago. However, most of the cases in the U.S. were travelers to other countries and developed symptoms once they returned to the U.S.
If you travel to a place with a high incidence and have no symptoms within 14 days after return to the U.S., you either never got dengue fever or have an asymptomatic case.
In the U.S., most cases have been in Florida, Hawaii, Texas, Arizona, and California. It is a good idea to engage in protective measures from mosquito bites: wear long sleeves and pants, use mosquito repellant, and do not let standing water accumulate.
Doing this will reduce your risk of getting dengue fever but also other viral infections spread by mosquitoes such as West Nile Virus.
Peter M. Hartmann, MD
Family Medicine & Psychiatry
