Dengue is a viral infection transmitted by the Aedes mosquito. It causes a range of clinical presentations from a self-limiting febrile illness called dengue fever to a potentially lethal complication called severe dengue. Severe dengue is characterized by plasma leakage, fluid accumulation, respiratory distress, severe bleeding, or organ impairment. The course of dengue hemorrhagic fever involves an initial febrile phase followed by a critical phase with plasma leakage and potential progression to shock, and finally a recovery phase.

1. Dengue
DR NARENDRA KUMAR YADAV
MD Community Medicine & Tropical Diseases, BPKIHS

2. Dengue:
Outline of the Chapter:
 Epidemiological triad of dengue
 Burden of Disease
Clinical Presentation
Warning signs of dengue
Diagnosis: Clinical methods and laboratory methods
CONTROL MEASURES
Clinical Management

3. Vector Borne Diseases:
M/C Vector borne disease in Nepal/India: Malaria
M/C VIRAL Vector borne disease in Nepal/India: Dengue
M/C Arboviral Vector borne disease in Nepal/India : Dengue

4. Mosquitoes:
ANOPHELES CULEX AEDES MANSONIA
 Malaria  Japanese Encephalitis(JE)
 Lymphatic Filariasis
 West Nile Fever
 Dengue
 CGF
 YF
 Zika
 RVF
 Brugian Filariasis
 CLEAN Water  DIRTY Water  ARTIFICIAL(Man
Made) COLLECTION
OF RAIN WATER
 AQUATIC PLANTS
Flight range:
3-5 kms 11 kms 100 m

5. Arboviral Diseases Classification:
GROUP: A GROUP: B OTHERS:
 CGF  Dengue
 Japanese Encephalitis(JE)
 Kyasanur Forest Disease(KFD)
 West Nile Fever
 Sandfly Fever

6. Dengue:
Dengue is a viral infection caused by dengue virus (DENV) that transmitted to
humans through the bite of an infected mosquitoes (Aedes species)
Cause: Group B Arbovirus
Dengue viruses have 4 serotypes:
1. DENV-1 (M/C/C of Epidemic)
2. DENV-2
3. DENV-3
4. DENV-4

7. Dengue:
VECTOR of Dengue: Aedes aegypti (Tiger Mosquito) and Aedes
Albopictus
Feeding Habits: Day Bitter (Bite during day time)
Resting Habits: Rest in the dark corners of houses
Breeding Habits: ARTIFICIAL(Man Made) COLLECTION OF RAIN WATER

8. Dengue:
Reservoir: Man and Aedes
Incubation Period: 3-10 days

9. Burden of Disease:
Dengue is found in tropical and sub-tropical climates worldwide,
mostly in urban and semi-urban areas.
About half of the world's population is now at risk of dengue with
an estimated 100–400 million infections occurring each year(WHO)
Mortality:
DF: <1%
Severe dengue: 5%

10. Epidemiological triad of dengue:
Agent: Dengue virus (DENV)
Host: Human & Aedes mosquito. Env: ARTIFICIALCOLLECTION OF RAIN WATER & Rainy season
Dengue

11. DEGUE: Clinical Presentation:
1. Asymptomatic Dengue Viral Infection Most of the cases are asymptomatic
2. Dengue Fever(DF)
AKA: Classical Dengue Fever
AKA: Break Bone Fever
 Fever (≥ 104 F)
 Retro-orbital pain/Headache/MYALGIA/ BONE PAIN
 Nausea/Vomiting
 RASH (Macular or Maculopapular)
3.Dengue Hemorrhagic Fever (DHF):
a. Febrile Phase
b. Critical Phase
c. Recovery Phase
 Fever
 Thrombocytopenia (PLT ≤ 1 lakh/mm3)
 Hemorrhagic manifestations: Gum bleeding, Epistaxis,
Hematemesis, Melena, Hematuria
 Evidence of leaky capillaries: Elevated Hematocrit (≥ 20%), Pleural
effusion, Ascites
 Leukopenia
4. Dengue Shock Syndrome(DSS):
 DHF +
 SHOCK

12. Rash in Dengue: The rash is typically macular or maculopapular and
may be associated with pruritus.

13. Severe Dengue:
Severe dengue is defined by ≥ 1 of the following:
1. Evidence of leaky capillaries:
 Shock
Fluid accumulation (P. Effusion, ascites): +-Respiratory Distress
2. Severe Bleeding: Shock
3. Organ failure( single or multiple organ failure)

14. Warning signs of dengue:
1. Restlessness/ OBTUNDATION
2. Persistent Vomiting: Dehydration
3. Mucosal Bleeding
4. Pleural Effusion: Dyspnea
5. Ascites
6. Hepatomegaly (2 cm below the costal margin)
7. Thrombocytopenia
8. Rise in Hematocrit

15. Dengue: Diagnosis:
CRITERIA FOR CLINICAL DIAGNOSIS:
Fever and ≥ 2/6 following features:
1. Retro-orbital pain/Headache/Myalgia/ Bone Pain
2. Nausea / Vomiting
3. Rash (macular or maculopapular)
4. Warning signs of dengue
5. Positive Tourniquet Test
6. Leucopenia

16. TORNIQUET TEST:
TORNIQUET TEST(Positive Tourniquet Test)
DF: ≥ 10 Petechiae/sq inch of skin in cubital fossa
DHF: ≥ 20 Petechiae/sq inch of skin in cubital fossa

17. Laboratory Diagnosis:
1. SEROLOGICAL Test:
NS-1 Antigen(non-structured protein of dengue virus)
IgM antibodies
IgG antibodies
2. Hematocrit (PCV) Count: Increases
3. PLT: Decreases
4. TLC: Decreases
5. LFT
6. CXR
7. USG

18. Control Measures:
1. Mosquito Control:
A. Physical Methods:
Source Reduction (Best): Elimination of breeding place
Use of mosquito nets
Wearing of full sleeves shirts and full pants
Use of mosquito repellent: creams, liquids, coils, mats
B. Chemical Methods:
Antiadult measures(Nerve/ Contact Poison): DDT, Pyrethrum, Malathion
Antilarval measures: Paris Green (Stomach Poison)
C. Biological Methods: Gambusia, Lebister, Poecilia (All are Larvivorous Fishes)

19. Control Measures:
2. Vaccines:
DENGVAXIA (Live): 0, 6 months, 12 months
Age: 9months- 45 years

20. Clinical Management:
Category Intervention
Dengue without warning sign: A OPD
Dengue with warning sign: B IPD
Dengue with risk factors: B IPD
Patient with severe dengue: C IPD
High risk patients: Infant, Elderly(>65 Years), Pregnancy, DM, HTN, IHD,
Asthma, CRF, Liver cirrhosis, PUD, Steroids, NSAIDs

21. Clinical Management:
Category A: OPD
Dehydration: ORS
Fever: Paracetamol & Cold sponging
C/I: Aspirin ( acetylsalicylic acid), Ibuprofen, Corticosteroids
Use insect repellant on patient & Elimination of breeding place
W/F: Bleeding, Signs of Plasma leakage, Warning signs of dengue.

22. Clinical Management:
Category B: warning sign +/ risk factors +
CRYSTALOIDS: NS/ RL
Colloids: iv albumin
Blood transfusion (BT)
 PLT (only when PLT < 50,000 with bleeding OR <10,000 without bleeding):
PRP
4hrly vitals monitoring
I/O monitoring

23. Clinical Management:
Category C: Patient with severe dengue:
CRYSTALOIDS: NS/ RL
 Bolus 1: 10 ml/kg/hr (1Hr)
 Bolus 2: 2 ml/kg/hr (15 min)
Colloids: iv albumin
 Blood transfusion (BT)
PLT (only when PLT < 50,000 with bleeding OR <10,000 without bleeding):
PRP

24. Criteria for discharge of patient:
1. Absence of fever for at least 24 hours without the use of anti-pyretic drugs.
2. Return of appetite.
3. Visible clinical improvement.
4. Good urine output.
5. Minimum of 2-3 days after recovery from shock.
6. No respiratory distress from pleural effusion or ascites.
7. Platelet count > 50000/cu.mm

25. MCQ:
Q. Dengue shock syndrome is characterized by the following except:
a. Hepatomegaly
b. Pleural effusion
c. Thrombocytopenia
d. Decreased hemoglobulin

26. Ans: d (Decreased hemoglobulin)

27. MCQ
Q. Which of the following statement is not about dengue:
a. Increase hematocrit
b. Decrease PLT
c. Positive tourniquet test
d. Vector Aedes aegypti usually bite during day time
e. Decrease hematocrit

28. Ans: e (Decrease hematocrit)

29. MCQ:
Q. Which is not true about dengue hemorrhagic fever:
a. Thrombocytopenia
b. Hepatomegaly
c. Shock
d. Plasma leaking

30. Ans: c (Shock)

31. MCQ
Q. Classical Dengue fever is transmitted by:
a. Culex fatigans
b. Culex vishnuii
c. Culex aegypti
d. Culex palpalis

32. Ans: c (Culex aegypti)

33. The End

34. Dengue Hemorrhagic Fever (DHF):
The course of DHF can be divided into 3 phases:
1. Febrile phase,
2. Critical phase and
3. Recovery phase.

35. Dengue Hemorrhagic Fever (DHF):
1. Febrile phase:
During the first few days the illness usually resembles classical Dengue fever.
 High grade fever with facial flushing, headache, anorexia, vomiting, abdomen discomfort,
pain abdomen, febrile seizure
Retro-orbital pain/Headache/MYALGIA/ BONE PAIN
Thrombocytopenia (PLT ≤ 1 lakh/mm3)
Evidence of leaky capillaries: Elevated Hematocrit (≥ 20%)
TORNIQUET TEST(Positive Tourniquet Test):
DF: ≥ 10 Petechiae/sq inch of skin in cubital fossa

36. Dengue Hemorrhagic Fever (DHF):
2. Critical phase:

37. Dengue Hemorrhagic Fever (DHF):
3. Recovery phase: