What are the other Names for this Condition? (Also known as/Synonyms)

• Breakbone Fever
• Classical Dengue Fever
• Dengue Hemorrhagic Fever

What is Dengue Fever? (Definition/Background Information)

• Dengue Fever (or Dengue Hemorrhagic Fever) is a viral disease caused by any one of four similar Dengue viruses: DENV 1, DENV 2, DENV 3, or DENV 4.
• It has been reported in the tropical and subtropical regions which include South East Asia, Western Pacific Islands, the Caribbean region, Central America, South America, Australia, and Africa.
• Dengue Fever is a vector-borne disease that is transmitted by mosquito bites. All ages, racial and ethnic groups, and both genders are equally likely to be infected with Dengue Fever. About 3 in 4 individuals infected with the condition do not show any signs or symptoms.
• The signs and symptoms of Dengue Fever occur in 1 in 4 infected individuals and can be mild to moderate. It includes nausea and frequent vomiting, fever, body rash, joint pain, muscle pain, and headaches. In severe cases, there can be bleeding from the gums and nose.
• Treatment is based upon the symptoms and may include adequate bed rest and medication. The prognosis of Dengue Fever is usually excellent, with majority recovering within a couple of weeks.

Who gets Dengue Fever? (Age and Sex Distribution)

Information on prevalence, gender preference, age of affliction, racial predilection, and geographical restriction/distribution:

• Individuals of all ages may be affected by Dengue Hemorrhagic Fever
• Both males and females are equally likely to be affected
• All races and ethnic groups are equally susceptible to Dengue Fever. However, the condition is more prevalent in South East Asia and Western Pacific Islands (per World Health Organization)

Note: Dengue Fever rarely occurs in the continental United States. It is endemic in Puerto Rico, and in many popular tourist destinations in Latin America and Southeast Asia; periodic outbreaks occur in Samoa and Guam.

What are the Risk Factors for Dengue Fever? (Predisposing Factors)

The risk factors for Dengue Fever include:

• Living in or visiting tropical and subtropical regions, where Dengue Fever is endemic; especially during the summer months, when mosquito breeding is at its peak. These regions include South East Asia, Western Pacific Islands, the Caribbean region, Central America, South America, Australia, and Africa
• Failure to take anti-mosquito precautions
• Outdoor camping

Note: The risk of contracting Dengue Fever is lower during the winter months.

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Dengue Fever? (Etiology)

• Dengue Hemorrhagic Fever is caused by an RNA virus belonging to the Flaviviridae family. This viral disease is caused by any one of four similar Dengue viruses: DENV 1, DENV 2, DENV 3, or DENV 4
• It is usually transmitted to humans by a bite from an infected mosquito. In the western hemisphere, the Aedes aegypti mosquito is the most important transmitter or vector of Dengue viruses

What are the Signs and Symptoms of Dengue Fever?

Symptoms begin between 4 days to a week after being infected. Nearly 75% of the individuals do not experience any signs or symptoms when infected by the virus. The signs and symptoms of Dengue Hemorrhagic Fever in 25% of the infected individuals include:

• Fatigue
• Skin rash can be present all over the body, but it is usually present on the chest, stomach, and back
• Joint pain (arthralgia) usually affecting the wrist, knee, and ankle, and sometimes affecting the fingers and toes
• Swelling of multiple joints can be seen due to fluid accumulation resulting in joint stiffness
• Muscle pain (myalgia)
• Blood in urine

There are 3 phases of Dengue Fever infection:

Phase 1: Fever phase

• Symptoms of the fever phase include high fever that can last for up to a week
• This is accompanied by body aches, headache, skin rash, continuous vomiting, intense abdominal pain, difficulty breathing, severe bleeding, signs and symptoms of shock

Phase 2: Critical phase

• The critical phase usually begins when the fever goes away and can last up to two days. Individuals usually show signs and symptoms that are getting better; however, this usually does not mean the patient is getting better
• In the critical phase, the blood pressure may suddenly drop, and the patient may go into deep shock, which may result in death in spite of all treatment measures. Different organs may get damaged, affecting their function

Phase 3:  Convalescent phase

• During the convalescent phase, the patient starts to get slowly better
• The skin rashes may start healing, which can cause intense itching

How is Dengue Fever Diagnosed?

Dengue Fever is diagnosed using the following methods:

• A thorough physical examination and a complete medical and travel history (including travel history to tropical and subtropical regions)
• Complete blood count with peripheral smear examination
• Blood test(s) to specifically look for Dengue Fever infection. The blood tests may show decreased platelet count, decreased white cell count, and increased erythrocyte sedimentation rate (ESR)
• Liver function test may show increased liver enzymes such as aspartate aminotransferase (AST) and alanine aminotransferase (ALT) 

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Dengue Fever?

Complications due to Dengue Fever could include:

• Prolonged signs and symptoms that can last several months
• 5% of individuals infected can have severe infection, which may be life-threatening

How is Dengue Fever Treated?

Currently, there is no cure or vaccine for Dengue Hemorrhagic Fever. The treatment measures to alleviate the symptoms include:

• Adequate bed rest
• Medication such as analgesics (pain-relievers)
• Drinking plenty of fluids

How can Dengue Fever be Prevented?

Preventive methods for Dengue Hemorrhagic Fever include taking adequate precaution from mosquito bites. There is currently no vaccination available against Dengue Fever. The following measures are useful in controlling transmission of the condition:

• Sleeping under mosquito nets (insecticide-treated mosquito nets) is a highly recommended practice in endemic areas
• Use mosquito repellent creams. It is also advisable to cover your skin by wearing clothes, such as full-length pants, full-sleeved shirts, etc.
• Maintain good sanitary conditions, to prevent mosquitoes from breeding. When possible, eliminate all potential mosquito habitats that contain standing water, where mosquitoes breed and lay their eggs, like water contained in temporary pools, old tires, discarded vessels, birdbaths, pots, rainwater puddles, etc.
• Sprays containing permethrin can be used on clothes; sprays containing DEET can be used on the skin
• Individuals who travel from a non-endemic region to Dengue Fever endemic region have to ensure that they are aware of the risk factors and basic preventive methods

Exposure to mosquito bites may be reduced if people are aware of biting patterns of the mosquitoes. The Dengue Fever-transmitting mosquitoes are most active during twilight and in the night. Avoiding outdoors to the extent possible or employing preventive actions during peak ‘biting’ hours may reduce risk.

What is the Prognosis of Dengue Fever? (Outcomes/Resolutions)

• The prognosis of Dengue Fever with treatment is generally excellent, with the majority of infected people recovering from the condition within a couple of weeks
• Dengue Fever has 4 distinct, yet closely related viruses known as DEN-1, DEN-2, DEN-3, and DEN-4. If any one type of Dengue Virus infects an individual, then infection with the virus once confers lifetime immunity to the individual. However, having immunity to one type of Dengue Fever virus does not imply protection from the other three virus types
• Dengue Fever in pregnancy may affect the developing fetus; however, the information is limited. The newborn can be affected at the time of birth causing symptoms of the infection

Additional and Relevant Useful Information for Dengue Fever:

• As per the World Health Organization (WHO), there are over 2.5 billion people living in Dengue Hemorrhagic Fever endemic regions
• Dengue Fever is now a reportable disease in the United States. It is leading cause of fever in travelers returning from Asia, the Caribbean and Latin America. Transmission has occasionally occurred in the continental United States in areas where the Aedes mosquitoes are found
• According to the WHO, over 30,000 cases of Dengue Fever, including over 100 deaths, have been reported so far in 2015 in Malaysia. In May 2015, the Centers for Disease Control and Prevention (CDC) advised travelers to be cautious while visiting Malaysia. The CDC recommends that travelers to this region take adequate precaution against mosquito bites
• It has been noted that this viral infection is not seen in altitudes above 4500 feet