Pathophysiology of Dengue Hemorrhagic Fever

Signs of dengue fever

Dengue fever, a contagious disease transmitted by the Aedes aegypti mosquito, infects between 50 million and 100 million people worldwide each year. Also known as breakbone or dandy fever, dengue fever is found in the tropical and subtropical regions of the world. Exposure to the flavivirus that causes dengue fever results in one of three pathophysiologies: dengue fever, the more severe dengue hemorrhagic fever (DHF) or dengue shock syndrome.

Transmission of Dengue Fever

Dengue fever is transmitted only through an infected mosquito or by contact with the blood of someone who is actively infected with one of the four viruses responsible for the fever. Infection with one of these viruses generally provides immunity from dengue fever for as much as a year after the illness. A small minority of cases of dengue fever develop into severe forms of the fever, DHF or dengue shock syndrome, which require hospitalization.

Symptoms of Dengue Fever

Early symptoms of dengue fever include headache, chills, backache, fever, nausea and joint pain. The initial fever may be as high as 104 degrees Fahrenheit at the onset of the illness and individuals may develop severe pain in the legs and behind the eyes. A rash consisting of patchy bright red spots may develop over the body after the first few days of illness.

Time Frame:Dengue Infection

After five to eight days of incubation, individuals infected with dengue fever develop symptoms abruptly. The initial symptoms of dengue fever last about six to seven days. The fever climbs rapidly in the first 48 to 96 hours of the illness and then may break for a day before elevating rapidly again. This second phase of the fever is often when a rash may appear on the limbs or chest.

Diagnosis of Dengue Fever

A diagnosis of dengue fever is typically not considered unless the individual has been in a tropical location where the virus is present such as Central America, South America, Africa or Asia. Clinically, individuals with dengue fever may develop a low white blood cell count by the second day of illness. This low white blood cell count, coupled with the "dengue triad" of fever, rash and headache, represent the most common diagnostic criteria for dengue fever.

Prevention of Dengue Fever

Dengue fever can only be prevented by avoiding travel to those tropical locations where the illness is present. If travel to tropical regions cannot be avoided, travelers should use barrier and chemical methods to prevent mosquito bites. Once contracted, treatment of dengue fever generally includes rest and fever/pain management. Total recovery from dengue fever may take several weeks.

Dengue Fever: Tropical and Subtropical Climates

Dengue fever is not present in the United States, although the Centers for Disease Control reports that 100 to 200 cases of dengue fever are brought into the United States each year. Dengue fever is considered endemic in tropical and subtropical areas and outbreaks have occurred in the Virgin Islands, the Caribbean and Puerto Rico.

References

• Centers for Disease Control and Prevention: Fact Sheet and Information on Dengue Fever