[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [RNA arboviruses](https://durgical.com/en/microbiology/groups/rna-arboviruses/) › Dengue virus [Microbiology](https://durgical.com/en/microbiology/) · [RNA arboviruses](https://durgical.com/en/microbiology/groups/rna-arboviruses/) # Dengue virus - Virus - Enveloped - Exam priority: high A virus spread by the Aedes aegypti mosquito. It causes high fever and body aches and, in some people, plasma leakage that can lead to shock. Updated 2026-11-01 Also called: DENV-1 to DENV-4, breakbone fever ## Key points - Flavivirus with single-stranded positive-sense RNA and four serotypes - A second infection with a different serotype raises the risk of severe dengue - Danger comes as the fever falls (critical phase, 24 to 48 hours) - NS1 or RT-PCR in the first week; IgM from day 3 to 5 - No NSAIDs or aspirin; paracetamol is the antipyretic of choice ## At a glance **Shape** Spherical, icosahedral capsid **Genome** Single-stranded, positive-sense RNA **Envelope** Enveloped **Family** Flaviviridae, genus Orthoflavivirus **Size** About 50 nm ## Morphology - Envelope carries glycoprotein E (attachment and fusion) and protein M - Four antigenically distinct serotypes (DENV-1, 2, 3 and 4) - The non-structural protein NS1 is secreted into blood and serves as a diagnostic antigen ## Transmission - Bite of a female Aedes aegypti (and Aedes albopictus), by day - The mosquito is infected when it bites a viraemic person and transmits after an extrinsic incubation period - Rarely: transfusion, transplant or vertical spread near delivery **Reservoir:** Humans (urban cycle); Non-human primates in sylvatic cycles on other continents **Vector:** Aedes aegypti (main), Aedes albopictus ### Isolation precautions What the care team adds to standard precautions. - Standard ## Virulence factors - Infection with one serotype gives lifelong immunity to it but only short-lived protection against the others - In a second infection with another serotype, non-neutralizing antibodies can help the virus enter monocytes (antibody-dependent enhancement) - NS1 and the inflammatory response damage the endothelial glycocalyx and raise capillary permeability - Plasma leakage causes haemoconcentration, effusions and shock; low platelets and coagulopathy favour bleeding ## Diseases it causes - Dengue: without warning signs, with warning signs, and severe dengue [Dengue →](https://durgical.com/en/conditions/dengue/) ## Clinical picture - Febrile phase (2 to 7 days): high fever, headache, retro-orbital pain, myalgia, arthralgia, rash - Critical phase: starts as the fever breaks and lasts 24 to 48 hours; this is when plasma leaks - Warning signs (WHO/PAHO 2009): severe continuous abdominal pain, persistent vomiting, fluid accumulation, mucosal bleeding, lethargy or restlessness, liver enlargement and a rising haematocrit with falling platelets - Severe dengue: shock from plasma leakage or respiratory distress from fluid, severe bleeding or severe organ involvement - Recovery phase: fluid is reabsorbed, blood pressure stabilizes and platelets recover ## Diagnosis - Days 0 to 7: NS1 antigen or RT-PCR on serum - IgM detectable from about day 3 to 5; the main test after day 7, lasting a few months - Positive tourniquet test, leukopenia and thrombocytopenia as classic clues - Serial haematocrit to watch for haemoconcentration - IgM cross-reacts with Zika and other flaviviruses ## Treatment There is no specific antiviral: care is supportive, with oral fluids or intravenous fluids guided by the classification and haematocrit, and paracetamol (acetaminophen) for fever. NSAIDs, aspirin and intramuscular injections are avoided because of bleeding risk. Drug class only; doses and regimens are set by the clinician from the current guideline. In Pharmacology: - [Paracetamol](https://durgical.com/en/pharmacology/paracetamol/) ## Prevention - Remove breeding sites: cover, scrub or discard containers holding still water - Repellent, long sleeves, bed nets and window screens - Community vector control and entomological surveillance - A live attenuated tetravalent vaccine is licensed in some countries for certain ages in high-transmission areas **Vaccine:** A live attenuated tetravalent vaccine is recommended by WHO for certain age groups in high-transmission settings; it is not part of Colombia's routine PAI schedule. ## In Colombia Colombia is hyperendemic: all four serotypes circulate, often at the same time, across almost all warm areas below roughly 2,200 m altitude. Dengue is a notifiable event in the INS SIVIGILA system, which classifies cases as dengue without warning signs, with warning signs and severe dengue; epidemic waves recur every few years. ## Memory aid "Fever gone, guard on": the drop in temperature opens the critical phase, the time to look hardest for warning signs. ## Test yourself Think of the answer, then tap the question to see it. ## When in dengue does plasma leakage happen? In the critical phase, which starts as the fever breaks and lasts about 24 to 48 hours. ## Which test fits a patient with two days of fever and suspected dengue? NS1 antigen or RT-PCR on serum, useful during the first seven days; IgM may still be negative. ## Why can a second dengue infection be more severe? Antibodies from the first infection that do not neutralize the new serotype can help the virus enter cells (antibody-dependent enhancement). ## What are three dengue warning signs? Severe continuous abdominal pain, persistent vomiting, mucosal bleeding; also fluid accumulation, lethargy, liver enlargement and a rising haematocrit. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/microbiology/dengue-virus/) ## Related - [Zika virus](https://durgical.com/en/microbiology/zika-virus/) - [Chikungunya virus](https://durgical.com/en/microbiology/chikungunya-virus/) - [Yellow fever virus](https://durgical.com/en/microbiology/yellow-fever-virus/) ## Related conditions - [Dengue](https://durgical.com/en/conditions/dengue/) ## What the colours mean **Gram-positive** Thick peptidoglycan wall: stains purple. **Gram-negative** Thin wall with an outer membrane: stains pink. **Acid-fast** Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain. [← Back to the group: RNA arboviruses](https://durgical.com/en/microbiology/groups/rna-arboviruses/) Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [Dengue](https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue) (World Health Organization (WHO), 2025); [Clinical Features of Dengue](https://www.cdc.gov/dengue/hcp/clinical-signs/index.html) (CDC, 2025); [Clinical Testing Guidance for Dengue](https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html) (CDC, 2025); [Dengue: Symptoms, Prevention and Treatments](https://www.paho.org/en/topics/dengue) (Pan American Health Organization (PAHO), 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/microbiology/dengue-virus/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/dengue-virus/