Miami-Dade County health officials announced the first locally acquired case of dengue fever in Miami in nearly sixty years, and urge residents to step up measures to prevent being bitten by mosquitoes. Authorities say the infected individual “made a full recovery from this illness”. They added that the diagnosis was made based on signs and symptoms, as well as confirmed laboratory tests. The patient, male, had not travelled outside the county in over two weeks, meaning he was infected locally.

According to the CDC (Centers for Disease Control and Prevention), there have been 28 reported cases of dengue fever this year in Key West – a first outside the US-Mexican border since 1945.

Miami-Dade health officials do not know how the man became infected. They explained that it was not the same strain as the one that infected people in Key West.

Dengue fever, otherwise known as breakbone fever is spread by a the Aedes aegypti mosquito, and more rarely by the Aedes albopictus mosquito which may carry four different viruses that can cause the disease. Dengue fever signs and symptoms can range from mild to severe, including DHF (dengue hemorrhagic fever) and dengue shock syndrome. Those with severe symptoms need to be admitted to hospital.

We have no vaccines to protect against dengue fever. The best way to avoid becoming infected is to take measures that reduce your chances of being bitten by a mosquito.

As long as the infection is treated early, or has not developed into DFH or dengue shock syndrome, the illness is easy to treat.

Approximately 100 million people develop dengue fever worldwide annually. It is more common in the urban and rural parts of subtropical and tropical regions, including South and Central American, some parts of Africa and Asia, the Pacific and the Caribbean. Unlike malaria, another mosquito-borne illness, dengue fever is just as common in urban and rural areas.

The World Health Organization informs that:

  • 40% of the world’s population is currently at risk from dengue fever.
  • Dengue fever is widespread in more than 100 countries.
  • In a number of Asian countries, dengue hemorrhagic fever is a leading cause of death and/or serious illness among children.
  • There were more than 890,000 reported cases of dengue fever in the Americas in 2007, 26,000 of them developed into dengue hemorrhagic fever.
  • People who have never been exposed to the virus have a 40% to 50% chance of becoming infected if bitten by a mosquito carrying the virus. In rarer cases the risk may be as high as 80%.
  • About 500,000 patients are hospitalized worldwide each year with dengue hemorrhagic fever, of whom about 2.5% die. A significant proportion of these hospitalized patients are children.
  • If left untreated, dengue hemorrhagic fever has a mortality rate of over 20%. If the patient has access to properly trained medical professionals, the death rate is less than 1%.

Signs and symptoms of mild dengue fever include aching joints and muscles, a rash that can come and go, high fever, a very bad headache, pain behind the eyes, nausea and vomiting. Symptoms usually appear up to seven days after becoming infected.

Signs and symptoms of dengue hemorrhagic fever may start off as mild and gradually get worse over a number of days, and may include (as well as those for mild dengue fever) bleeding gums, clammy skin, nosebleeds, damage to lymph and blood vessels, black vomit and feces (caused by internal bleeding), blood platelet levels drop making it harder for the blood to clot, very sensitive stomach, weak pulse, and small spots under the skin.

Signs and symptoms of dengue shock syndrome, the most severe form of dengue fever, may include (as well as those for mild symptoms) disorientation, rapid drop in blood pressure (hypotension), very bad stomach pain, intense and regular vomiting, and blood vessels leaking fluid.

To read about diagnosis, causes and prevention of dengue fever in more detail, click here.

Written by Christian Nordqvist