dengue virus

1. Dengue Virus

2.  Characterized by fever of sudden onset,
headache, retro bulbar pain, conjunctival
infection, pain in the back and joints
 Break bone fever
 Lymphadenopathy, and maculopapaular
lesion

3.  Four sero types
 DEN 1
 DEN 2
 DEN 3
 DEN 4
 Transmitted by aedes aegypti

4. Clinical features
 Two forms
 Classical dengue fever
 Dengue in more serious forms with
hemorrhagic manifestations

5. Classical dengue fever
 Affects older children and adults
 Fever, headache, pain in muscles and bones
 Fever- biphasic
 Incubation period 5-8 days
 Maculopapular rash appears on 3rd or 4th day
 Febrile illness lasts for 10 days
 Rarely fatal


6. Dengue in more serious forms with
hemorrhagic manifestations
 Dengue hemorrhagic fever( DHF) and
dengue shock syndrome (DSS)
 Mostly in 5-10 years age group
 In area where multiple dengue viruses
cause disease
 It appears to be hyper immune response
 It is seen in patients previously infected
dengue virus

7.  On reinfection with a different type of
dengue virus antibody formed against the
first virus reacts with the second serotype
virus forming immune complexes

8.  Symptoms- fever associated with
hemorrhagic rash, thrombocytopenia,
and shock
 Mortality 5-10%

9. Laboratory diagnosis
 SPECIMENS:
 For antibody and antigen detection –
serum
 For isolation of virus and PCR- serum,
plasma, whole blood, autopsy
specimens, mosquitoes collected
innature

10.  Hematological diagnosis:
 Thrombocytopenia
 haemoconcentrtion

11.  Microbiological diagnosis:
 Detection of antibody
 IgM ab in serum
 Appear after 5 days
 ELISA is used
 IgG ab appears later than IgM

12.  Detection of NS1 antigen
 Immunochroamtographic test
 Rapid test
 Detects on the first day of fever
 Takes 15 mins

13.  Isolation of virus:
 Done by inoculating clinical specimens in
to mosquitoes, mosquitoes cell lines or
suckling mice
 Further identification is done by
fluorescent antibody technique

14.  PCR:
 Viral RNA can be detected in clinical
specimens by RTPCR

15. Prophylaxis
 Elimination of mosquitoes
 No effective vaccine
 Vaccine Under clinical trails