Group 4 submitted a report on Dengue virus to their professor. The report discussed the classification of Dengue virus as a flavivirus and outlined its structure, genome, and life cycle. It described the history and prevalence of Dengue, noting it was first described in 1780 and is now found throughout the tropics and subtropics. The report also examined Dengue outbreaks in Pakistan since 1994 and discussed transmission between humans and mosquito vectors as well as symptoms, diagnosis, treatment and prevention of Dengue fever.

2. Group number: 4th
Members :
Amna shoukat 7211
Aneela shaukat 7215
Amina Bashir 7227
Faiqa Zafar 7259
Course Tittle: Virology
Submitted to : Sir Usman Ali Ashfaq
Semester : 5th
GCUF

4. Virus classification
 Group:Group IV ((+)ssRNA)
 Order:Unassigned
 Family:Flaviviridae
 Genus:Flavivirus
 Species:Dengue virus

5. Dengue Virus(DENV) – A Flavivirus
• Flavivirus are spherical
and 40- 60 nm in
diameter.
 Genome – Positive sense,
single sense RNA, 11 kb in
size.
 RNA infectious
Enveloped virus .
Three structural
polypeptides
 Seven non structural
 Replication in cytoplasam
.

6. History and prevalence of Dengue
virus
 This disease was first described in 1780.
 The virus was isolated by Sabin in 1944 in the tropical
regions of Asia, Africa, and Central and South
America.
 Dengue is prevalent throughout the tropics and
subtropics including northern Argentina, northern
Australia,Brazil,Panama, Philippines, Malaysia etc.

7. Prevalence of Dengue Infection

8. Outbreak in Pakistan
 The first case of Dengue Fever was detected in Pakistan in
the year 1994 in Karachi.
 The first outbreak of Dengue Fever was in the year 2006.
 Since then dengue cases detected per year are on the rise.

9. Out break in Pakistan 2011
Sr
No
Province Confirmed Cases
1. Punjab 2170
2. Sindh 176
3. Khyber Pakhtoon Khuwa 08
4. Azad Jammu Kashmir 05

10. Serotypes
 4 serotypes of dengue viruses
 DENV-1
 DENV-2
 DENV-3
 DENV-4
 A serotype is a group of viruses classified together based
on their antigens on the surface of the virus.
 They have 60-80% homology between each other.

12. Pathogenesis
 Presence of existing Dengue antibody, associated with
fresh viral infection with new serotype complexes and
forms within few days of the second dengue infection.
 Non neutralizing enhancing antibodies promote infection
of higher number of Mononuclear cells.

13. Dengue Fever
 Dengue Hemorrhagic Fever is an acute infectious viral disease usually
affecting infants and young children.
 Causative agent: Aedes aegypti and
Aedes albopictus.
 Most favourable season for
occurrence of this fever is mainly
rainy season (sep &oct).

14. Flavi Virus

15. ALTERNATIVE NAMES
 Hemorrhagic dengue
 Dengue shock syndrome
 Philippine hemorrhagic fever
 Thai hemorrhagic fever
 Singapore hemorrhagic fever

16. Classification
• Severe, frank type – with flushing, sudden high fever,
severe hemorrhage, followed by sudden drop of
temperature, shock and terminating in recovery or death.
• Moderate – with high fever, but less hemorrhage, no
shock.
• Mild – with slight fever, with or without petechial
hemorrhage but epidemiologically related to typical cases
usually discovered in the course of investigation of typical
cases.

17. Vectors of Dengue Fever
 Aedes aegypti
Aedes aegypti is not
found in Hong Kong
at present.
 Aedes albopictus
Aedes albopictus is very
common in Hong Kong.

18. Vectors
Habitual Behaviour of
Aedes aegypti
Habitual Behaviour of
Aedes Albopictus
 Usually breed in
stagnant water.
 Usually active in
dark or shaded
places outdoors,
but indoor activity is
also possible.
 Female mosquitoes feed
on human blood.
 They are most active 2
hours before sunset
(around 5pm to 6pm) and
at around 8am to 9am.

20. Transmission
 Transmitted to humans through bites of infective female
Aedes mosquitoes.
 Aedes aegypti
 Aedes albopictus
 Humans are the main amplifying host.
 Incubation period 5-8 days.
 The virus circulates in the blood of infected humans for 2-7
days, at approximately the same time they have fever.

21. 21
Transmission
Infected
person
Healthy person
Infected
mosquito
Incubation Period: 3 to 14 days
Most commonly 4 to 7 days

22. UNDERLYING MECHANISM:

23. Aedes aegypti
Aedes
albopictus

24. Life cycle of Aedes Mosquito
Stagnant water
1-2 days
EggsLarvaePupae
2-3 days4-5 days

25. LIFE CYCLE OF DENGUE FROM SPECIE TO SPECIE

27. Symptoms of Dengue Fever
Dengue
Triad
 Headaches
 High grade fever
 Swollen glands
 Vomiting
 Muscle joints pain
 Basic symptoms in 90% of patients
 Settles in two weeks

28. Diagnostic Lab Test
 Dengue IgM test.
 Indirect IgG ELISA test.
 False positive
dengue serology.
• Virus isolation.
 Non-structural protein-1
(NS1 Antigen).
 Polymerase chain
reaction(PCR).
 Positive tourniquet test

29. 29
Treatment
• At present, there is no drug that can treat
dengue fever effectively. Patients infected
with classical dengue usually recovers in
1 to 2 weeks.
• For serious cases, supportive treatments
are provided by hospitals.
• If you suspect that you have dengue fever,
you should seek medical treatment
promptly.

30. 30
Treatment
 Wiping the body with warm water and
proper use of anti-fever drugs that can
relieve the fever
.
 Don’t take aspirin-containing drugs
because they worsen
the haemorrhage.

31. Prevention of Dengue Fever
Focus on vector control
 Use spray and repellent oil
 Drain stagnant water sites
 Use mosquito nets
 Wear full clothes at dusk and
dawn
 Fumigation

32. Control of Dengue
 Control of Mosquito breeding
places.
 Anti mosquito measures.
 Use of Insecticides.
 Screened windows and doors
can reduce exposure to vectors.

33. References
 Ghai Essential Pediatrics, 7th Edition, CBS publication, page 196-200.
 Medicine Prep Manual for Undergraduates, 4th Edition, Elsevier
Publication, page 751-755.
 Dengue haemorrhagic fever: diagnosis, treatment, prevention and
control. 2nd edition. Geneva : World Health Organization. :
http://www.who.int/csr/resources/publications/dengue/Denguepublicatio
n/en/index.html
 Dengue- Guidelines for Diagnosis, Treatment, Prevention & Control.
New Edition 2009. world Health Organization:
http://whqlibdoc.who.int/publications/2009/9789241547871_eng.pdf
 http://www.who.int/csr/disease/dengue/en/
 Clinical Practice Guidelines- Management of Dengue Infection in Adults.
Revised 2nd Edition. Ministry of Health Malaysia.: http: www.moh.gov.my