Dengue is a mosquito-borne viral infection found worldwide in tropical and subtropical regions. It is transmitted by the Aedes aegypti mosquito. The document discusses the definition, epidemiology, virus, transmission cycle, clinical stages and symptoms, investigations, diagnosis, treatment, prevention and control of dengue fever. Key points include that dengue is caused by four distinct virus serotypes, causes flu-like symptoms and in severe cases can lead to dengue hemorrhagic fever or dengue shock syndrome, and prevention focuses on eliminating mosquito breeding sites and seeking early medical care if infected.

1. Guess ?????

4. Dengueis a
mosquito-borne
infection found in
tropical and sub-
tropical regions
around the world.
DEFINITION

5. General facts about DENGUE
It is nicknamed break- bone fever
About 50 -100 million infections world wide
every year.
Dengue fever is passed by infected female
AEDES AEGYPTI mosquitoes.
Dengue is caused by flaviviruses.

6. Epidemiology
In India first outbreak of
dengue was recorded in 1812
A double peak hemorrhagic
fever epidemic occurred in
India for the first time in
Calcutta between July 1963 &
March 1964
In New Delhi, outbreaks of
dengue fever reported in 1967

8. `

9. Dengue Virus
• Flavivirus are spherical and 40- 60 mm
in diameter.
• RNA virus
• Enveloped
• Three structural polypeptides two are
glycosylated
• Replication in cytoplasm

10. • Most potent vector having epidemic
potential is A. aegypti
• Other species are
Aedis albopictus,
A. Stegomyia,
A. Ploynesiensis,
A. Scutellaris and
A. Finalaya
In India A. tigris
Dengue Virus

14. How do Aedes mosquito transmitted
disease

16. TRANSMISSION CYCLE OF
DENGUE

17. TRANSMISSION CYCLE OF
DENGUE

18. Few common andfavoured
breeding places/sites of
A. aegypti

19. Risk factors
• Age – common in all groups but in southeast Asia children are
more affected.
• Pre existing anti dengue antibody
Previous infection
Maternal antibody
• Higher risk in secondary infections
• Higher risk with two or more serotype circulating
simultaneously
• Host genetics ; race (white may be great risk than black )
• Virus strain : certain genetic strain virus causes dengue in
primary infection

20. Causes of dengue
Dengue (DF) is caused by one of four closely
related, but antigenically distinct, virus
serotypes (DEN-1, DEN-2, DEN-3, and DEN-
4), of the genus Flavivirus.
Infection with one of these serotypes provides
immunity to only that serotype for life,
Causes of dengue fever

21. Physiology of dengue

22. Thrombocytopenia

23. Dengue fever is a
severe, flu-like
illness that affects
infants, young
children and adults,
but seldom causes
death.
SYMPTOMS

24. Four dengue clinical stages
Undifferentiate
d fever
Classic
dengue
fever
Dengue
hemorrhagic
fever (DHF)
Dengue
shock
syndrome
(DSS)
Clinical stages of dengue

25. Manifestations of the dengue syndrome
Asymptomatic
Undifferentiated
fever
No h'rage Unusual
hemorrhage
Dengue Fever
DHF I & II DSS
Dengue Hemorrhagic Fever
(plasma leakage)
Symptomatic
Dengue virus
Infection

26. Undifferentiated fever
• Most common presentation
• Silent transmission
• Incubation period of 3-14 days
• Sudden onset of fever
• Severe headache (retro orbital)

27. • Myalgias and arthalgias
(Break bone fever)
• Nausea and vomiting
• Rash may be present at different
stages of illness
- Maculpapular
- Petechial
- Erthematous
• Hemorrhagic manifestation
Undifferentiated fever

28. Dengue hemorrhagic fever
• Develops 3rd – 7th day of illness
• Rapid onset of plasma leakage , altered hemostasis,
damage to the liver resulting in severe fluid losses and
bleeding
• Skin hemorrhage
• Gingival & nasal bleeding, hematuria
• GI bleeding- haetemesis, melena, haematochezia

29. • Plasma leakage due to increase capillary
permeability ; manifest as hemoconcentration
• Pleural effusion & ascites
• Bleeding due to capillary fragility
• Liver damage manifest as increase in level of
liver enzymes, low albumin level, deranged
parameters (PT, PTT)
Dengue hemorrhagic fever

30. How to diagnose dengue
??

31. Physical Examination may reveal the following:
 Low BP
 A weak, rapid pulse
 Rash
 Red eyes
 Red throat
 Swollen glands
 Enlarged liver (hepatomegaly)

32.  Hematocrit
 Platelet count
 Electrolytes
 Coagulation studies
 Liver enzymes
 Blood gases
Investigations

33.  Torniquet test (causes petechiae below the
torniquet)
 X -ray of the chest (may demonstrate pleural
effusion)
 Serologic studies (demonstrate antibodies to
Dengue viruses)
 Serum studies from samples taken during acute
illness and convalescence (High in titer to
Dengue
antigen)
Investigations

34. How to do a Tourniquet test
• Tourniquet test is performed by inflating a blood
pressure cuff to a point mid-way between the
systolic and diastolic pressures for five minutes.
• A test is considered positive when 10 or more
petechiae per 2.5 cm2 (1 inch) are observed.
• In DHF, the test usually gives a definite positive
result (i.e. >20 petechiae).

35. Characteristic findings in dengue fever are
as follows:
• Thrombocytopenia (platelet count < 100 x
109/L
• Leukopenia
• Mild to moderate elevation of aspartate
aminotransferase and alanine aminotransferase
values (liver enzymes)

36. In patients with dengue hemorrhagic fever, the
following may be present:
• Increased hematocrit level secondary to
plasma extravasation and/or third-space fluid
loss
• Hypoproteinemia
• Prolonged prothrombin time (PT)
• Prolonged activated partial thromboplastin
time(APTT)
• Decreased fibrinogen

37. Shock
Encephalopathy
Residual brain damage
Seizures
Liver damage

38. For severe dengue, medical care
by physicians and nurses experienced
with the effects and progression of the
disease can save lives.
TREATMENT

39. Maintenance of the patient's
body fluid volume is critical to
severe dengue care.
TREATMENT

40. • No Anti viral therapy available
• Symptomatic management in Majority of cases
• Dengue Hemorrhagic fever to be treated with
suitable fluid replacement
• No Vaccine available, difficult in view of four
serotypes.
TREATMENT

43. Recognition of the disease
Isolation of patient (screening or
sleeping under the mosquito net)
Epidemiological investigation
Case finding and reporting
Health Education

45. 1. Eliminate the vector by:
 Changing water and scrubbing sides of lower
vases once a week.
 Destroy breeding places of mosquito by cleaning
surroundings
 Proper disposal of rubber tires, empty bottles and
cans.
 Keep water containers covered.
2. Avoid too many hanging clothes inside the
house.
3. Residual spraying with insecticides

47. Seek Early
Treatment

48. Stop- all that you’re doing!
Look-for the breeding sites
and destroy these!
Listen-for the government
advisories
Habit
PREVENTION

49. Is Dengue a Fatal Disease ?
Yes,….. But don’t press the
panic button!
It can be controlled and
treated if handled properly.

50. Keep
in
mind

51. Your queries please