Description on Dengue

1. Dengue: An Overview
• Dengue is a mosquito-borne viral illness
caused by dengue virus (DENV), which belongs
to the Flaviviridae family. It is endemic in
many tropical and subtropical regions.

2. Epidemiology
• Over 100 countries report dengue cases. WHO
estimates 100-400 million dengue infections
annually. Southeast Asia and the Western
Pacific are most affected.

3. Etiology: The Dengue Virus
• Dengue virus is a positive-sense, single-
stranded RNA virus. Transmitted primarily by
Aedes aegypti and Aedes albopictus
mosquitoes.

4. Serotypes of Dengue Virus
• There are 4 serotypes: DENV-1, DENV-2,
DENV-3, and DENV-4. Secondary infection by a
different serotype increases risk of severe
disease.

5. Transmission: Aedes Mosquito
• Aedes mosquitoes are day-biters. They breed
in stagnant water. Lifespan up to 2-4 weeks;
efficient vectors for dengue transmission.

6. Host Factors
• Age, genetic factors, and previous dengue
exposure influence susceptibility. Young
children and elderly may exhibit more severe
outcomes.

7. Pathogenesis
• Virus replicates in dendritic cells, spreads to
lymph nodes and bloodstream. Increased
vascular permeability leads to plasma leakage.

8. Immune Response in Dengue
• Primary infection elicits lasting immunity to
the infecting serotype. Secondary infection
may trigger antibody-dependent
enhancement (ADE).

9. Clinical Features: Overview
• Symptoms include high-grade fever, headache,
retro-orbital pain, myalgia, and rash.
Incubation period: 4-10 days after the
mosquito bite.

10. Dengue Fever Stages
• Dengue progresses through 3 phases: febrile
(2-7 days), critical (1-2 days), and recovery (2-3
days). Close monitoring is essential.

11. Warning Signs
• Warning signs include abdominal pain,
persistent vomiting, mucosal bleeding,
hepatomegaly, and rapid increase in
hematocrit.

12. Severe Dengue
• Severe dengue involves plasma leakage,
severe bleeding, or organ impairment. Can
lead to shock and multi-organ failure.

13. Laboratory Diagnosis
• Laboratory diagnosis includes complete blood
count, liver function tests, NS1 antigen,
IgM/IgG ELISA, and RT-PCR.

14. NS1 Antigen and Serology
• NS1 antigen is detectable early in infection.
IgM detected after day 5. IgG indicates
secondary infection.

15. Complete Blood Count Findings
• Thrombocytopenia, leukopenia, and
hemoconcentration are common findings.
Platelet count monitoring is essential.

16. Imaging in Dengue
• Ultrasound may show ascites, pleural effusion.
Chest X-ray reveals pulmonary edema in
severe cases.

17. Differential Diagnosis
• Malaria, chikungunya, Zika, leptospirosis, and
typhoid fever should be considered as
differential diagnoses.

18. Management: General Principles
• Treatment is supportive. No specific antiviral
therapy exists. Close monitoring for warning
signs is necessary.

19. Fluid Management in Dengue
• Fluid resuscitation is the cornerstone of severe
dengue management. Balance necessary to
avoid overload.

20. Complications and Treatment
• Complications include shock, hemorrhage,
organ failure. Platelet transfusion may be
needed in critical cases.

21. Prevention and Control
• Vector control, environmental management,
community awareness are preventive
strategies.

22. Vaccines for Dengue
• Dengvaxia is the first licensed dengue vaccine.
Only recommended for those with prior
dengue infection.

23. Recent Advances in Dengue
Research
• Research includes development of tetravalent
vaccines, antiviral drugs, and genetically
modified mosquitoes.