Dengue fever is caused by one of four viruses that are transmitted by infected Aedes mosquitoes. The transmission of the disease occurs when a mosquito bites an infected person and subsequently bites an uninfected person. The bite actually transmits the small amount of blood necessary to infect someone with dengue fever. Diagnosis is made through blood tests that scan for antibodies to dengue viruses.
Infection usually becomes symptomatic 5-6 days after the infecting bite. The first symptoms are a high fever, generally 104-105 degrees F (40 degrees C), vomiting, nausea and a headache. Joint and muscular pain follow within the next days, and a flat, red rash may appear and spread from the torso to the limbs and face. The severe pains gave Dengue its nickname: break-bone fever.
Most symptoms of the disease subside within seven days of their onset, and patients are expected to make a full recovery. In a small number of cases, dengue hemorrhagic fever may develop, which has a much higher fatality rate in children and individuals with suppressed immune systems.
Every year some 20 million people contract dengue fever leading to 24,000 deaths worldwide. About 100 dengue fever infections are reported annually in the U.S., mostly from travelers returning from the tropics and residents in the southern states.
Like most viral illnesses, there is no effective cure for the disease. There are four strains of the virus and an infected person can re-experience symptoms if exposed to another strain of the virus.
Fever is the main symptom of dengue fever. In many cases, the body temperature will be very high, often reaching up to 105 degrees F (40.56 degrees C). Many people may also have extreme body aches, rashes and vomiting. Sometimes, a severe form of this disease known as dengue hemorrhagic fever can develop. When this happens, more serious symptoms such as bleeding underneath the skin, nose bleeds, blood vessel damage, bleeding from the mouth may occur, which has a much higher fatality rate in children and individuals with suppressed immune systems
Other common symptoms of dengue fever are joint and muscle pain, nausea, vomiting and headaches. Symptoms don't usually appear until about six days after being bitten by a mosquito that carries the virus.
The mosquito that causes symptoms of dengue fever is the striped Aedes aegypti. They are more common during the rainy season, and they often breed around human settlements in water containers like empty flowerpots or cans, so it's not unusual for them to come into contact with people. There are four closely related viruses that can cause symptoms of dengue fever, and all of them are sometimes carried by these mosquitoes. The virus is not contagious from person to person, and the only way to get it is through a mosquito bite.
Aedes aegypti is only found in tropic and sub-tropic regions of the world, so those are the places where symptoms of dengue fever are most common. Central and South America, Africa, the Middle East and Southeast Asia are all areas where dengue fever can be a major problem. In the United States, there have been a few cases of the illness, but it is still relatively rare. Some scientists worry that it could become more common in the near future, partially because of global warming.
People who develop symptoms of dengue fever only die about 1% of the time, but recovery can be relatively lengthy. The acute period of the illness involving high fever can last as long as two weeks. After the fever goes away, people will generally feel weakened for several more weeks before they recover fully.
Like most other viruses, there is no actual way to cure dengue fever. The illness generally has to run its course. Doctors normally focus on helping patients by relieving symptoms and making sure they receive enough rest and fluid so that their immune systems are able to fight effectively. Symptoms of this illness may become quite overwhelming. For this reason, the more the ill person rests, the easier it may be to combat the symptoms. The most common pharmaceutical treatments are medicines for pain and fever, like ibuprofen and acetaminophen.
As this illness can cause an extremely high body temperature, an acetaminophen may be taken as treatment. The acetaminophen may greatly lower the body temperature. It will generally take more than one dosage to see temperature changes. Commonly, doctors recommend taking acetaminophen instead of aspirin or a type of nonsteroidal anti-inflammatory, because this can make some symptoms worse. For example, if one of the individual's symptoms is bleeding, these medications could make this symptom worse.
Treatment may also include increasing the individual's daily intake of fluids. If vomiting is one of the person's most profound symptoms, there is a chance that he or she may become dehydrated. For this reason, drinking a good deal of fluids can greatly decrease the likeliness of this happening. In addition, the fluids may also help reduce the extremely high fever.
Hospitalization may also be dengue fever treatment. This may be necessary if the symptoms become so severe that they are life threatening. One example of this would be profuse bleeding. In this event, a blood transfusion may be necessary. Additionally, an individual who becomes extremely dehydrated due to excessive or repeated vomiting may be given intravenous fluids to treat this particular symptom.
A dengue fever vaccine is in development, but isn't generally available. If you're living or traveling in an area where dengue fever is known to be, the best way to avoid dengue fever is to avoid being bitten by mosquitoes that carry the disease.
If you are living or traveling in tropical areas where dengue fever is common, these tips may help reduce your risk of mosquito bites:
Stay in air-conditioned or well-screened housing. It's particularly important to keep mosquitoes out at night.
Reschedule outdoor activities. Avoid being outdoors at dawn, dusk and early evening, when more mosquitoes are out.
Wear protective clothing. When you go into mosquito-infested areas, wear a long-sleeved shirt, long pants, socks and shoes.
Use mosquito repellent. Permethrin can be applied to your clothing, shoes, camping gear and bed netting. You can also buy clothing made with permethrin already in it. For your skin, use a repellent containing at least a 10 percent concentration of DEET.
Reduce mosquito habitat. The mosquitoes that carry the dengue virus typically live in and around houses, breeding in standing water that can collect in such things as used automobile tires. Reduce the breeding habitat to lower mosquito populations.