Dengue fever

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Dengue fever
Rash caused by dengue fever
Synonyms	Breakbone fever, dandy fever
Pronounce	N/A
Specialty	N/A
Symptoms	Fever, headache, muscle pain, joint pain, skin rash
Complications	Dengue hemorrhagic fever, dengue shock syndrome
Onset	4–10 days after exposure
Duration	2–7 days
Types	N/A
Causes	Dengue virus spread by Aedes mosquito
Risks	Living or traveling in tropical areas
Diagnosis	Blood test
Differential diagnosis	N/A
Prevention	Mosquito control, vaccine
Treatment	Supportive care, intravenous fluids, pain relief
Medication	N/A
Prognosis	N/A
Frequency	100–400 million cases per year
Deaths	40,000 per year

Alternate names

Dengue hemorrhagic fever; Dengue shock syndrome; Philippine hemorrhagic fever; Thai hemorrhagic fever; Singapore hemorrhagic fever; Hemorrhagic dengue; DF; Dengue virus infection

Definition

Dengue fever (DF), caused by dengue virus, is an arboviral disease characterized by an initial non-specific febrile illness that can sometimes progress to more severe forms manifesting capillary leakage and hemorrhage (dengue hemorrhagic fever, or DHF) and shock (dengue shock syndrome, or DSS).

File:Symptoms man - dengue.webm

Symptoms of Dengue

File:Dengue.jpg

Dengue

Epidemiology

DF is found in the tropics worldwide, especially in Southeast Asia, the Pacific region, and the Americas, with 40% of the global population at risk. An estimated 50 to 100 million cases of DF, 500,000 hospitalizations, and 20,000 deaths occur yearly worldwide.

Cause

• Over 25 different viruses cause viral hemorrhagic fever.
• Dengue virus belongs to the Flaviviridae family, genus Flavivirus. Four distinct serotypes, with significant strain variation, are recognized.
• Dengue is caused by one of any of four related viruses: Dengue virus 1, 2, 3, and 4.¬† For this reason, a person can be infected with a dengue virus as many as four times in his or her lifetime.

Signs and symptoms

• Mild symptoms of dengue can be confused with other illnesses that cause fever, aches and pains, or a rash.
• Graphic of human body showing most common symptom of dengue is fever with any of the following: eye pain, headache, muscle pain, rash, bone pain, nausea/vomiting, joint pain

The most common symptom of dengue is fever with any of the following:

• Nausea, vomiting
• Rash
• Aches and pains (eye pain, typically behind the eyes, muscle, joint, or bone pain)
• Any warning sign
• Symptoms of dengue typically last 2–7 days. Most people will recover after about a week.

Transmission

• Dengue viruses are spread to people through the bites of infected Aedes species mosquitoes (Ae. aegypti or Ae. albopictus).
• These mosquitoes typically lay eggs near standing water in containers that hold water, like buckets, bowls, animal dishes, flower pots, and vases.
• These mosquitoes prefer to bite people, and live both indoors and outdoors near people.
• Mosquitoes that spread dengue, chikungunya, and Zika bite during the day and night.
• Mosquitoes become infected when they bite a person infected with the virus. Infected mosquitoes can then spread the virus to other people through bites.

From mother to child

• A pregnant woman already infected with dengue can pass the virus to her fetus during pregnancy or around the time of birth.
• To date, there has been one documented report of dengue spread through breast milk.
• Because of the benefits of breastfeeding, mothers are encouraged to breastfeed even in areas with risk of dengue.
• Dengue in pregnancy
• Rarely, dengue can be spread through blood transfusion, organ transplant, or through a needle stick injury.

Diagnosis

Most state health departments and many commercial laboratories perform dengue diagnostic testing. Nucleic acid amplification tests (NAATs)

• For patients with suspected dengue virus disease, NAATs are the preferred method of laboratory diagnosis.
• NAATs should be performed on serum specimens collected 7 days or less after symptom onset.
• Laboratory confirmation can be made from a single acute-phase serum specimen obtained early (‚â§7 days after fever onset) in the illness by detecting viral genomic sequences with rRT-PCR or dengue nonstructural protein 1 (NS1) antigen by immunoassay.
• Presence of virus by rRT-PCR or NS1 antigen in a single diagnostic specimen is considered laboratory confirmation of dengue in patients with a compatible clinical and travel history.

Serologic tests

• IgM antibody testing can identify additional infections and is an important diagnostic tool. However, interpreting the results is complicated by cross-reactivity with other flaviviruses, like Zika, and determining the specific timing of infection can be difficult.
• Later in the illness (‚â•4 days after fever onset), IgM against dengue virus can be detected with MAC-ELISA. For patients presenting during the first week after fever onset, diagnostic testing should include a test for dengue virus (RT-PCR or NS1) and IgM.
• For patients presenting >1 week after fever onset, IgM detection is most useful, although NS1 has been reported positive up to 12 days after fever onset . In the United States, both MAC-ELISA and RT-PCR are approved as in vitro diagnostic tests.
• IgM in a single serum sample strongly suggests a recent dengue virus infection and should be presumed confirmatory for dengue if the infection occurred in a place where other potentially cross-reactive flaviviruses (such as Zika, West Nile, yellow fever, and Japanese encephalitis viruses) are not a risk.
• PRNTs can resolve false-positive IgM antibody results caused by non-specific reactivity, and, in some cases, can help identify the infecting virus. However, in areas with high prevalence of dengue and Zika virus neutralizing antibodies, PRNT may not confirm a significant proportion of IgM positive results. PRNT testing is available through several state health departments and CDC.

Cross-reactive flaviviruses

• If infection is likely to have occurred in a place where other potentially cross-reactive flaviviruses circulate, both molecular and serologic diagnostic testing for dengue and other flaviviruses should be performed.
• People infected with or vaccinated against other flaviviruses (such as yellow fever or Japanese encephalitis) may produce cross-reactive flavivirus antibodies, yielding false-positive serologic dengue diagnostic test results.
• IgG antibody testing
• IgG detection by ELISA in a single serum sample is not useful for diagnostic testing because it remains detectable for life after a dengue virus infection.

Treatment

No treatment: No specific antiviral agents exist for dengue. Supportive care is advised:

• Patients should be advised to stay well hydrated and to avoid aspirin (acetylsalicylic acid), aspirin-containing drugs, and other nonsteroidal anti-inflammatory drugs (such as ibuprofen) because of their anticoagulant properties.
• Fever should be controlled with acetaminophen and tepid sponge baths.
• Febrile patients should avoid mosquito bites to reduce risk of further transmission.

Severe Dengue

• For those who develop severe dengue, close observation and frequent monitoring in an intensive care unit may be required.
• Prophylactic platelet transfusions in dengue patients are not beneficial and may contribute to fluid overload.
• Administration of corticosteroids has no demonstrated benefit and is potentially harmful to patients; corticosteroids should not be used except in the case of autoimmune-related complication (e.g., hemophagocytic lymphohistiocytosis, immune thrombocytopenia purpura).

Prevention

Prevent dengue by avoiding mosquito bites.

• All four dengue viruses are spread primarily through the bite of an infected Aedes species (Ae. aegypti and Ae. albopictus) mosquito. These mosquitoes also spread chikungunya and Zika viruses.
• The mosquitoes that spread dengue are found in most tropical and subtropical regions of the world, including many parts of the United States.
• Ae. aegypti and Ae. albopictus bite during the day and night.
• A dengue vaccine is available for use in some parts of the world, including United States territories.

NIH genetic and rare disease info

• NIH info on Dengue fever

Dengue fever is a rare disease.