Dengue Fever in India: Symptoms, Causes & Treatment | aihealz
Infectious DiseasemoderateICD-10 · A90
Dengue Fever.Care & specialists in India
In India, dengue Fever is managed by infectious diseases. Dengue fever is the world's most common mosquito-borne viral illness, with WHO modeling estimating 390 million infections each year, of which approximately 96 million are symptomatic. The virus is transmitted by Aedes aegypti and Aedes albopictus mosquitoes biting during the day in tropical and subtropical regions.
Dengue fever (ICD-10: A90 dengue fever without warning signs; A91 dengue hemorrhagic fever / severe dengue) is an arboviral infection caused by one of four dengue virus serotypes (DENV-1, DENV-2, DENV-3, DENV-4), all single-stranded RNA flaviviruses. The virus is transmitted by day-biting Aedes aegypti and Aedes albopictus mosquitoes; humans are the principal reservoir in the urban transmission cycle that drives most outbreaks. After a 4-10 day incubation period, infection causes a self-limited febrile illness in most patients, with high fever, severe headache, retro-orbital pain, myalgia, arthralgia, maculopapular rash, and a characteristic platelet drop. The 2009 WHO classification recognizes three categories: dengue without warning signs, dengue with warning signs (abdominal pain, persistent vomiting, mucosal bleeding, lethargy, hepatomegaly), and severe dengue (plasma leakage with shock or respiratory distress, severe bleeding, or severe organ impairment).
key facts
Prevalence
Approximately 390 million infections per year (96 million symptomatic) per Bhatt 2013 modeling; case reports rising globally year over year
Demographics
All ages affected; severe dengue concentrated in children in long-endemic Asian countries and increasingly in adults in newly affected regions
Avg. age
Acute disease across all ages; peak severe dengue historically in children 4-14 in endemic Asia and Latin America
Global cases
More than 5.2 million cases reported in 2019 (WHO), with continuing increases in 2023-2024; over 100 countries now have endemic transmission
Specialist
Infectious Disease
ICD-10
A90
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How you might notice it
The key symptoms of Dengue Fever are: Sudden onset of high fever (often 39-40°C) lasting 2-7 days after a 4-10 day incubation following an Aedes mosquito bite., Severe frontal or retro-orbital headache that worsens with eye movement., Diffuse myalgia and arthralgia — the classic 'break-bone fever' — affecting back, limbs, and joints., Maculopapular rash appearing day 3-5 of illness, often described as 'islands of white in a sea of red'., Mild bleeding manifestations: petechiae, gum bleeding, epistaxis, mild menstrual irregularity., Nausea, vomiting, abdominal discomfort, and reduced oral intake., Marked fatigue, anorexia, and altered taste that can persist for weeks after fever resolves..
01Sudden onset of high fever (often 39-40°C) lasting 2-7 days after a 4-10 day incubation following an Aedes mosquito bite.
02Severe frontal or retro-orbital headache that worsens with eye movement.
03Diffuse myalgia and arthralgia — the classic 'break-bone fever' — affecting back, limbs, and joints.
04Maculopapular rash appearing day 3-5 of illness, often described as 'islands of white in a sea of red'.
Suspect dengue in any patient with sudden high fever and at least two of: severe headache, retro-orbital pain, myalgia, arthralgia, rash, mucosal bleeding, leukopenia, or thrombocytopenia, who has resided in or visited an active transmission area within the past two weeks. Concurrent testing for chikungunya, Zika, leptospirosis, malaria, and typhoid is essential in returning travelers because the differential is broad. Dengue NS1 antigen by ELISA or rapid lateral-flow test is highly sensitive in the first 5-7 days of illness; IgM antibody becomes positive 4-5 days after symptom onset and persists for 2-3 months; IgG is detectable from day 7 in primary infection (low titer) and earlier and at higher titer in secondary infection. RT-PCR is the most specific test but limited in availability outside reference laboratories. Daily complete blood count is the workhorse of clinical management — falling platelet count and rising hematocrit signal plasma leakage and the start of the critical phase. Liver enzymes, coagulation studies (PT, aPTT, fibrinogen), and serial vital signs (pulse rate, blood pressure, pulse pressure, capillary refill, urine output) drive fluid management. Imaging is reserved for evaluating effusion, ascites, or unusual presentations. Pediatric and obstetric cases warrant specialist input. The transition from febrile to critical phase around day 3-7 is the highest-risk period and warrants close monitoring or hospitalization in patients with warning signs.
Key tests
01
Dengue NS1 antigen (rapid or ELISA)Detects dengue virus NS1 protein in the first 7 days of illness — the workhorse first-line test
02
Dengue IgM and IgG ELISADetects antibody response from day 4-5 onward; supports diagnosis when NS1 is negative
03
Dengue RT-PCR (serum)Most specific test for dengue viral RNA and serotype identification; available in reference laboratories
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Treatment & cost
medical treatments
✓Paracetamol (acetaminophen) 500-1000 mg every 4-6 hours (max 4 g/day adults; weight-based in children)
✓Oral rehydration solution for dengue without warning signs
✓Colloid solutions (gelatin, starch alternatives) for refractory shock
surgical options
Therapeutic thoracentesis or paracentesis for symptomatic effusion or ascitesSymptomatic relief in over 90% of treated effusions; underlying plasma leakage typically resolves spontaneously within 24-48 hours
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Causes & risk factors
known causes
Bite of an infected Aedes aegypti or Aedes albopictus mosquito
Day-biting Aedes mosquitoes acquire dengue virus by feeding on viremic humans and transmit to others 8-12 days later. A. aegypti is the principal urban vector; A. albopictus extends transmission into peri-urban and rural areas and parts of temperate climate zones.
Secondary infection with a different dengue serotype
Lifelong immunity to one serotype does not protect against the other three. Subsequent infection with a different serotype carries approximately 7-fold higher risk of severe dengue through antibody-dependent enhancement, in which non-neutralizing cross-reactive antibodies facilitate virus entry into immune cells.
Outbreak conditions and high vector density
Rainy season accumulation of water in containers, urban crowding, climate change extending Aedes range, and inadequate vector control drive periodic outbreaks. The 2023-2024 global surge has been notable in Bangladesh, India, Brazil, and southern Europe.
Vertical (mother-to-fetus) and perinatal transmission
Dengue virus can cross the placenta and cause fetal loss, premature delivery, low birth weight, and severe neonatal infection if maternal viremia overlaps with delivery. Vertical transmission occurs in roughly 10-25% of pregnancies with peripartum viremia.
Blood transfusion, organ transplantation, needle-stick injury
Rare nosocomial transmission routes documented. Blood services in endemic regions screen donors or defer those reporting recent fever and travel; healthcare workers must use universal precautions.
risk factors
Residence or travel in an active transmission areaenvironmental
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Living with it
01Use insect repellent containing DEET (20-30%), picaridin, IR3535, or oil of lemon eucalyptus on exposed skin during the day in endemic regions and reapply per label.
02Wear long sleeves, long trousers, and permethrin-treated clothing during peak Aedes activity (dawn and dusk).
03Stay in air-conditioned or screened accommodation; sleep under a permethrin-treated bed net if the room is not screened.
04Eliminate breeding sites around the home: empty flowerpots, change water in bird baths twice weekly, cover or discard tires and containers, clear blocked gutters.
05Consider the dengue vaccine if you meet eligibility criteria (Qdenga for ages 4-60 in licensed countries; Dengvaxia for ages 9-45 with documented prior dengue infection).
06Use mosquito protection during the first week of illness if infected to prevent onward transmission to vectors and family members.
recommended foods
•Adequate oral fluids (2-3 liters per day in adults) — water, oral rehydration solution, fresh fruit juices
•
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When to seek help
why see an infectious disease
Infectious disease and pediatric specialist input is recommended for any patient with warning signs, severe dengue, pregnancy, or significant comorbidities. Critical care involvement is essential for dengue shock syndrome. Travel medicine clinics support vaccine decisions in eligible patients.
Dengue without warning signsMost common form. Acute febrile illness with high fever, headache, retro-orbital pain, myalgia, arthralgia, rash, and mild bleeding (petechiae, gum bleeding). Self-limited and managed at home with paracetamol and oral fluids.
Dengue with warning signsSevere abdominal pain, persistent vomiting, mucosal bleeding, lethargy or restlessness, hepatomegaly more than 2 cm, rapid platelet drop with rising hematocrit, or clinical fluid accumulation (ascites, pleural effusion). Requires hospitalization for intravenous fluid management and close monitoring.
Severe dengueSevere plasma leakage with shock or respiratory distress, severe bleeding, or severe organ impairment (liver, CNS, heart). Mortality 1-5% with good care, over 20% without. Requires intensive care and meticulous fluid management.
Dengue hemorrhagic fever (legacy 1997 WHO classification)Original WHO classification grades I-IV based on hemorrhagic manifestations and shock. Grades III and IV (dengue shock syndrome) correspond to severe dengue. The 2009 classification is now preferred for clinical decision-making.
Expanded dengue syndromeAtypical manifestations including encephalopathy, encephalitis, myocarditis, hepatitis, acute kidney injury, and acute respiratory distress syndrome. Recognized when standard categories do not capture the clinical presentation.
Living with Dengue Fever
Timeline
Acute fever resolves over 2-7 days. Critical phase lasts 24-48 hours after defervescence. Platelet count typically recovers over 5-10 days. Hematocrit normalizes over 2-3 days after the critical phase. Fatigue and reduced exercise tolerance may persist for 2-6 weeks during convalescence.
Lifestyle
01Rest during the acute and critical phases; gradually resume normal activity over 1-2 weeks of convalescence.
02Drink at least 2-3 liters of fluid daily during the febrile phase and as advised by the clinician.
03Inspect the skin daily for new petechiae or bleeding; report any to the clinician promptly.
04Track symptoms and seek urgent care for warning signs (severe abdominal pain, persistent vomiting, mucosal bleeding, lethargy).
05Continue insect repellent and screened housing for at least one week after recovery to prevent re-infection or onward transmission.
06Disclose recent travel and dengue history at any future medical encounter, especially before vaccination decisions or transfusion.
Daily management
01Take paracetamol for fever and pain; never use aspirin or NSAIDs unless cleared by your doctor.
02
Complementary approaches
Carica papaya leaf extract (traditional remedy)Widely used in South and Southeast Asia for thrombocytopenia. Some small trials suggest modest increases in platelet count but high-quality evidence is limited and it does not replace standard supportive care.
Structured rest and gradual reintroduction of activity during convalescenceFatigue, weakness, and reduced exercise tolerance commonly persist for weeks after acute dengue. Graded return to work and exercise reduces post-dengue fatigue syndrome impact.
Choosing a doctor
Look for clinicians and hospitals familiar with WHO 2009 dengue case management, with established fluid management protocols and rapid access to NS1 and serology testing. In endemic regions, designated dengue care wards offer the best outcomes. Ensure pediatric and obstetric services are available for relevant patients.
Dengue fever is a viral disease caused by one of four dengue virus serotypes and transmitted by day-biting Aedes mosquitoes. It causes sudden high fever, severe headache, retro-orbital pain, myalgia, arthralgia, rash, and a characteristic platelet drop. Most patients recover within a week but 0.5-1% develop severe dengue.
How is dengue transmitted?▾▴
Dengue is transmitted through the bite of infected Aedes aegypti or Aedes albopictus mosquitoes that bite during the day. Vertical mother-to-fetus transmission can occur near delivery. Rare nosocomial routes include blood transfusion, organ transplantation, and needle-stick injury. Person-to-person spread does not occur directly.
What are the warning signs of severe dengue?▾▴
Severe abdominal pain, persistent vomiting, mucosal bleeding (gums, nose, gut), lethargy or restlessness, hepatomegaly more than 2 cm, rapid platelet drop with rising hematocrit, and clinical fluid accumulation (ascites or pleural effusion) all warrant hospitalization. They mark the start of the critical phase around day 3-7.
Can dengue kill you?▾▴
Yes. Severe dengue with shock, respiratory distress, severe bleeding, or organ failure can be fatal. Mortality is under 1% with optimal supportive care but exceeds 20% without it. Early recognition and meticulous fluid management are the most important determinants of survival.
How is dengue diagnosed?▾▴
Dengue NS1 antigen test is the first-line test in the first 7 days; IgM antibodies become positive from day 4-5. RT-PCR is the most specific test where available. Daily complete blood count tracks platelet count and hematocrit. Concurrent testing for chikungunya, Zika, and malaria is essential.
What is the treatment for dengue?▾▴
Treatment is supportive: paracetamol for fever, oral fluids, rest, and serial monitoring. Aspirin and NSAIDs are contraindicated because they worsen bleeding. Hospitalization with intravenous fluid management is needed for warning signs or severe dengue. There is no specific antiviral therapy.
Can you get dengue more than once?▾▴
Yes. Each of the four dengue serotypes (DENV-1 to DENV-4) produces lifelong immunity to itself only. A second infection with a different serotype carries approximately 7-fold higher risk of severe dengue through antibody-dependent enhancement. People in endemic areas may have multiple infections in a lifetime.
Is there a dengue vaccine?▾▴
Yes. TAK-003 (Qdenga) is licensed in many countries for ages 4-60 and offers approximately 80% protection against confirmed dengue in seropositive recipients. CYD-TDV (Dengvaxia) is licensed for ages 9-45 with documented prior dengue infection. Eligibility and recommendations vary by country.
Should pregnant women get dengue vaccine?▾▴
Both CYD-TDV (Dengvaxia) and TAK-003 (Qdenga) are live attenuated vaccines and are contraindicated in pregnancy. Pregnant women should rely on strict mosquito-bite prevention. Prior to becoming pregnant, eligible women can discuss vaccination with their travel medicine provider.
Why are aspirin and ibuprofen avoided in dengue?▾▴
Aspirin and NSAIDs inhibit platelet function and impair gastric mucosal protection, both of which raise bleeding risk in dengue. Dengue already lowers platelet counts and damages capillary integrity, so concomitant NSAID use can precipitate serious gastrointestinal or other hemorrhage. Paracetamol is the safe alternative.
How long does dengue fever last?▾▴
Acute fever lasts 2-7 days. The critical phase begins as fever resolves and lasts 24-48 hours. Full recovery from acute illness takes 1-2 weeks, with fatigue and reduced exercise tolerance persisting for 2-6 weeks in some patients. Severe disease may extend hospitalization to 5-10 days.
Can children get dengue?▾▴
Yes. Children are highly susceptible and historically have shown the highest rates of severe dengue in long-endemic Asian countries. Severe dengue in children may present subtly with lethargy and reduced oral intake rather than obvious bleeding; close clinical observation is essential.
How do you prevent dengue?▾▴
Use DEET, picaridin, or IR3535 insect repellent during the day, wear long sleeves and trousers, stay in air-conditioned or screened accommodation, and eliminate standing water around the home. Vaccination is available for eligible individuals in many countries. Vector control by public health authorities is essential during outbreaks.
Does papaya leaf extract help dengue?▾▴
Some small clinical trials suggest modest improvement in platelet recovery with Carica papaya leaf extract, but high-quality evidence is limited and it should not replace standard supportive care and fluid management. Patients using papaya leaf preparations should still attend medical review and laboratory monitoring.
How is dengue different from flu?▾▴
Both cause fever and myalgia, but dengue is mosquito-borne and produces retro-orbital pain, severe joint pain (break-bone fever), maculopapular rash, and a characteristic platelet drop. Influenza is droplet-spread, has prominent respiratory symptoms (cough, sore throat, nasal congestion), and responds to oseltamivir within 48 hours of onset.
Can you exercise after dengue?▾▴
Avoid strenuous exercise during the acute and critical phases. Light walking is appropriate once fever has resolved and warning signs have settled. Full return to high-intensity exercise should wait at least 1-2 weeks during convalescence, with normalization of CBC and clinician clearance for athletes.
Is dengue contagious from person to person?▾▴
Dengue is not contagious through normal contact, droplets, or sexual transmission. It requires the Aedes mosquito vector to complete the transmission cycle. Vertical transmission from mother to fetus near delivery and rare nosocomial transmission via transfusion or needle-stick are exceptions.
What is dengue hemorrhagic fever?▾▴
Dengue hemorrhagic fever is the legacy 1997 WHO classification for severe dengue with bleeding, hemoconcentration, and plasma leakage. The 2009 WHO classification renamed grades III and IV as 'severe dengue' to better guide bedside care. Both terms describe the most dangerous forms of dengue.
Why are platelets low in dengue?▾▴
Dengue virus infects megakaryocytes and platelets, induces antibody-mediated platelet destruction, and triggers bone-marrow suppression. The platelet count typically falls dramatically over the febrile and critical phases, sometimes below 20,000/µL, before recovering as the infection resolves. Most patients do not need platelet transfusion.
When should I go to hospital for dengue?▾▴
Go to hospital immediately for severe abdominal pain, persistent vomiting, mucosal bleeding, lethargy, dizziness on standing, cold extremities, or any of the WHO warning signs. Patients with comorbidities, pregnancy, age over 65, or fast deterioration should also be assessed in hospital regardless of warning signs.
Can dengue cause long-term problems?▾▴
Most patients recover fully. Some experience post-dengue fatigue syndrome with weakness, hair loss, and reduced exercise tolerance for weeks to months. Severe dengue with prolonged shock or organ failure can have residual effects on kidney, heart, or brain function in a small minority of survivors.
•Severe respiratory distress with hypoxia — pleural effusion, pulmonary edema, or ARDS
•Massive hemorrhage (hematemesis, melena, hemoptysis, or per vaginal) — severe dengue with bleeding
•Altered consciousness, seizures, or focal neurological deficits — dengue encephalopathy
•Marked jaundice with rapidly worsening liver enzymes (AST/ALT above 1,000) — severe hepatitis variant of dengue
04
Serial complete blood count (platelets and hematocrit)Tracks platelet decline and hemoconcentration — the core indicators of plasma leakage and the critical phase
05
Liver function tests and coagulation studiesDocuments hepatic involvement and coagulopathy, common in moderate-severe dengue
06
Bedside ultrasound for effusion and ascitesDetects plasma leakage manifesting as pleural effusion, ascites, or gallbladder wall thickening
07
Concurrent testing for chikungunya, Zika, malaria, typhoid, and leptospirosisDistinguishes dengue from major co-circulating differential diagnoses with different management implications
Outlook
Acute dengue without warning signs has an excellent prognosis: more than 99% of patients recover within 1-2 weeks. Mortality in severe dengue falls from over 20% without specific care to under 1% with adherence to WHO fluid management protocols. The critical phase around days 3-7 is the highest-risk period; once a patient has had 48 hours of stable hemodynamics and rising platelets, recovery is reliable. Long-term sequelae are uncommon; some patients report post-dengue fatigue syndrome with weakness, hair loss, and reduced exercise tolerance for weeks to a few months. Infection produces lifelong immunity to that serotype only; secondary infection with a different serotype carries the highest risk for severe disease. The widening adoption of TAK-003 (Qdenga) vaccine has the potential to change population-level outcomes over the next decade.
More than 100 countries across tropical and subtropical Asia, Latin America, Africa, the Pacific, and parts of Europe have endemic dengue transmission. WHO and CDC publish updated country-by-country risk maps.
Prior dengue infection with a different serotypenon-modifiable
Secondary infection with a different serotype carries approximately 7-fold higher risk of severe dengue, the strongest single risk factor for life-threatening disease.
Age (children in endemic Asia, older adults in newer regions)non-modifiable
Severe dengue concentrated in children 4-14 years in long-endemic Asian countries (multiple serotypes co-circulate, secondary infection common). Older adults in newly affected regions carry higher mortality from severe dengue, in part because of comorbidities.
Pregnancynon-modifiable
Pregnant women infected near term face elevated risk of premature delivery, low birth weight, and vertical transmission to the neonate. Antenatal screening is recommended in outbreak settings.
Diabetes, sickle cell disease, chronic kidney disease, and obesity are associated with more severe dengue and higher mortality. Asthma and atopy have been associated with dengue hemorrhagic fever in some studies.
Inadequate vector control around the homemodifiable
Standing water in flowerpots, tires, water-storage containers, blocked gutters, and discarded bottles support Aedes breeding. Eliminating these sources cuts household exposure and outbreak intensity dramatically.
Outdoor activity during peak Aedes biting hoursmodifiable
Aedes mosquitoes bite primarily during daylight hours with peaks at dawn and dusk. Outdoor work, sports, and travel during these hours raise exposure substantially.
Easily digestible foods (rice, soft fruits, broth, plain yogurt) during the febrile phase
•Iron-rich foods during convalescence if anemia is documented
•Adequate protein (1.0-1.2 g/kg/day) to support recovery
foods to avoid
•Aspirin and NSAIDs (ibuprofen, naproxen, diclofenac, mefenamic acid) — increase bleeding risk in dengue
•Alcohol — interacts with hepatic dysfunction common in dengue
•Spicy, oily, or heavy foods during the acute phase that may worsen nausea
•Untested 'miracle remedies' or untreated water that may add an enteric infection
01Access to dengue NS1 antigen, IgM serology, and ideally RT-PCR
0224-hour laboratory for hematology and biochemistry monitoring
03Pediatric and intensive care services for severe cases
04Defined dengue case management protocols based on WHO 2009 framework
05Blood transfusion services and platelet availability
Essential facilities
Tropical and infectious disease wardsPediatric inpatient servicesAdult and pediatric intensive care unitsTravel medicine and pre-travel vaccination clinicsPublic health surveillance and vector control programs
Drink at least 2-3 liters of fluid each day, more if losses are high.
03Monitor for warning signs: severe abdominal pain, persistent vomiting, mucosal bleeding, lethargy, sudden cooling, dizziness on standing.
04Attend daily review and laboratory testing as advised during the febrile and critical phases.
05Use mosquito repellent and stay in screened accommodation through the first week to prevent onward transmission.
06Resume normal activity gradually over 1-2 weeks of convalescence.
Exercise
Rest during the acute and critical phases. Light walking once fever has resolved and warning signs have settled. Avoid strenuous exercise for at least 1-2 weeks during convalescence to allow full hematologic recovery. Athletes returning from dengue should have a normal CBC and clinician clearance before returning to high-intensity training.