Dengue

Dengue is an acute febrile illness caused by any of the four dengue virus (DENV) serotypes, transmitted primarily by infected mosquitoes. It is also known as breakbone fever or dandy fever. The illness can range from being asymptomatic or a mild fever to a severe, life-threatening condition. The World Health Organization (WHO) classifies dengue into three categories: dengue without warning signs, dengue with warning signs, and severe dengue. Most people recover from dengue within one to two weeks. With timely and appropriate medical care, the case fatality rate for severe dengue is typically below 1%. However, without proper management, it can be much higher.

Symptoms

Sudden high fever (40°C/104°F)
Severe headache (often behind the eyes)
Muscle and joint pains
Nausea
Vomiting
Rash
Swollen glands
Severe abdominal pain (warning sign)
Persistent vomiting (warning sign)
Rapid breathing (warning sign)
Bleeding gums or nose (warning sign)
Fatigue (warning sign)
Restlessness (warning sign)
Blood in vomit or stool (warning sign)
Mucosal bleeding (warning sign)
Fluid accumulation (e.g., around lungs or in abdomen) (warning sign)
Secondary rash ('isles of white in a sea of red') during recovery
Severe itching during recovery
Encephalopathy (atypical)
Seizures (atypical)
Myocarditis (atypical)
Acute liver failure (atypical)

Causes & Risk Factors

Infection with Dengue virus (DENV), a single-stranded RNA virus of the family Flaviviridae, genus Flavivirus
Transmission through the bites of infected female Aedes aegypti mosquitoes (primary vector)
Transmission through the bites of infected female Aedes albopictus mosquitoes (secondary vector)
Mosquitoes become infected when they bite a person with DENV in their blood
Rare cases of maternal-fetal (vertical) transmission
Rare cases of transmission through blood transfusion
Rare cases of transmission through organ transplantation
Previous infection with a different dengue virus serotype (major risk factor for severe dengue due to Antibody-Dependent Enhancement - ADE)
Young children and infants (higher risk for severe dengue in some populations)
Certain genetic predispositions
Chronic diseases such as diabetes, asthma, and cardiovascular disease
Living in or traveling to tropical and sub-tropical areas, especially urban and semi-urban areas
Lack of piped water in housing
Presence of open water storage containers in housing
Inadequate window and door screens in housing
Lack of awareness about dengue prevention and mosquito breeding sites

Diagnosis

Medical history, including travel to or residence in a dengue-endemic area
Physical examination for fever, rash, signs of bleeding, or positive tourniquet test
Virological tests such as NS1 antigen detection (rapid diagnostic test, high sensitivity in first 1-7 days of fever)
Virological tests such as Reverse transcriptase-polymerase chain reaction (RT-PCR) to detect viral RNA (most sensitive in first 5-7 days of illness)
Serological tests such as IgM antibody detection (appears around day 4-5 of illness, indicates recent infection)
Serological tests such as IgG antibody detection (appears after IgM, indicates past infection; significant rise in titers or high acute levels may suggest secondary infection)
Complete Blood Count (CBC) showing leukopenia (low white blood cells)
Complete Blood Count (CBC) showing thrombocytopenia (platelet count <100,000 cells/mm³)
Complete Blood Count (CBC) showing rising hematocrit (hemoconcentration, >20% increase from baseline) as a sign of plasma leakage
Probable dengue diagnosis based on living in/traveling to endemic area, plus fever and two of: nausea/vomiting, rash, aches and pains, positive tourniquet test, leukopenia
Confirmed dengue diagnosis requires laboratory confirmation

Treatment Options

Supportive care, as there is no specific antiviral medication for dengue
Bed rest for dengue without warning signs
Adequate fluid intake (oral rehydration salts, fruit juice, water) for dengue without warning signs
Antipyretics like Paracetamol (Acetaminophen) for fever and pain
AVOID non-steroidal anti-inflammatory drugs (NSAIDs) such as Ibuprofen, Naproxen, and Aspirin due to increased bleeding risk
Close monitoring of vital signs, fluid balance, hematocrit, and platelet count for dengue with warning signs (requires hospital admission)
Intravenous (IV) fluid therapy if oral intake cannot be maintained for dengue with warning signs
Emergency treatment and intensive care for severe dengue
Judicious intravenous fluid resuscitation with isotonic crystalloids (e.g., Normal Saline, Ringer's Lactate) to manage plasma leakage and shock in severe dengue
Careful monitoring to avoid fluid overload in severe dengue
Blood transfusions for management of severe bleeding in severe dengue
Management of severe organ impairment (e.g., liver failure, myocarditis) in an ICU setting for severe dengue
Education on warning signs for patients managed at home, with advice to return to hospital immediately if any appear
Monitoring of hospitalized patients until out of the critical phase (typically 24-48 hours after fever subsides)

Frequently Asked Questions

What is the difference between dengue fever and severe dengue?

Dengue fever can be a mild illness, while severe dengue is a more serious form characterized by severe plasma leakage (which can lead to shock), severe bleeding, or severe organ impairment. Warning signs indicate a risk of progressing to severe dengue.

Can I get dengue more than once?

Yes, you can get dengue more than once. There are four different types (serotypes) of the dengue virus. Infection with one type provides lifelong immunity to that specific type, but only partial and temporary protection against the others.

If I get dengue a second time, will it be worse?

Yes, a second infection with a different dengue virus type is considered a major risk factor for developing severe dengue.

How long after a mosquito bite do symptoms start?

Symptoms typically start 4 to 10 days after being bitten by an infected mosquito.

Is dengue contagious from person to person?

No, dengue is not typically contagious from person to person through direct contact. It is primarily spread through the bite of an infected mosquito. Rare cases of transmission from mother to baby, through blood transfusions, or organ transplants have been documented.

What are the specific warning signs I need to watch for at home?

Warning signs that suggest dengue could become severe include severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums or nose, feeling very tired or restless, and blood in your vomit or stool. If you experience any of these, seek medical help immediately.

When should I go to the emergency room?

You should go to the emergency room immediately if you experience any warning signs, such as severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums or nose, extreme fatigue, restlessness, or blood in vomit or stool.

Why can't I take ibuprofen or aspirin for the fever and pain?

You should avoid non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, naproxen, and aspirin because they can increase your risk of bleeding, which is a potential complication of dengue. Paracetamol (acetaminophen) is generally recommended for fever and pain.

Is there a specific medicine or cure for dengue?

No, there is no specific antiviral medication or cure for dengue. Treatment focuses on managing symptoms and providing supportive care, especially for severe cases.

How long does the illness last?

Most people with uncomplicated dengue recover within one to two weeks.

What tests are used to diagnose dengue?

Diagnosis involves blood tests such as the NS1 antigen test and RT-PCR to detect the virus early, and IgM/IgG antibody tests to confirm recent or past infection. A complete blood count (CBC) can also show changes like low white blood cells and platelets, and rising hematocrit.

How long will my platelet count be low?

Platelet counts are closely monitored during dengue illness, especially in severe cases. Your healthcare provider will track your platelet levels as part of your overall management.

Do I need a platelet transfusion?

Severe bleeding, a complication of dengue, may require blood transfusions. Your healthcare team will determine if transfusions are necessary based on your specific condition.

Is there a vaccine for dengue?

Yes, there are dengue vaccines available, such as Dengvaxia® and Qdenga®.

Who should get the dengue vaccine?

Recommendations vary by vaccine and country. Dengvaxia® is recommended by WHO for individuals aged 9-45 years in endemic areas who have had a previous dengue infection. Qdenga® is approved in some countries for broader age groups and can be given regardless of prior dengue exposure. Your doctor can advise based on local guidelines and your specific situation.

How can I protect my family from getting dengue?

You can protect your family by preventing mosquito bites. This includes eliminating standing water around your home, using insect repellents, wearing long-sleeved clothing, and using window screens or mosquito nets.

What should I do if I am pregnant and think I have dengue?

If you are pregnant and suspect you have dengue, you should seek medical attention immediately. Maternal infection, especially near term, can increase risks for both you and your baby, including maternal complications, preterm birth, low birth weight, and fetal distress.

Can dengue be transmitted from a pregnant mother to her baby?

Yes, the dengue virus can be transmitted from a mother to her infant during the perinatal period (around the time of birth). Neonatal dengue can present with fever, low platelet count, and rash, and severe disease can occur.

What are the long-term effects of having dengue?

Most patients recover fully. A subset may experience prolonged fatigue, known as post-dengue fatigue syndrome. The long-term impact of severe organ involvement is less well-understood.

Is it safe to travel to a country where dengue is common?

If you are traveling to tropical or sub-tropical areas where dengue is common, it is important to take precautions to prevent mosquito bites, as living in or traveling to these areas is a risk factor for dengue.

What kind of insect repellent is most effective?

Insect repellents containing DEET, picaridin, or IR3535 are recommended for personal protection against mosquito bites.

Does dengue cause hair loss?

The provided medical information does not indicate hair loss as a known symptom or complication of dengue.