Dengue is a mosquito-borne viral infection transmitted by Aedes mosquitoes. It causes flu-like symptoms including fever, headache, muscle and joint pain. In some cases it can develop into severe dengue which involves bleeding, low blood pressure and organ impairment. There are four types of dengue virus and infection provides lifetime immunity to that specific type. Prevention involves eliminating breeding sites for Aedes mosquitoes and using protective measures like nets, clothing and repellents when outdoors. There is currently no vaccine or specific treatment, with care focused on relieving symptoms.

1. Dengue: Infection and Treatment
by
Mahmoud Lubbad

2. Alternative Names
• Onyong- Nyang Fever
• West Nile Fever
• Break Bone Fever
• Dengue like Disease

3. Dengue
• The word dengue is derived from African
word denga: meaning fever with
hemorrhage .
• Is caused by virus transmitted of bites of
mosquito Aedes.

4. History
• The first outbreak that resembles a
disease now recognized as dengue fever
was that described by Benjamn Rush in
Philadelphia, Pennsylvania in 1780.

5. Problem statement
• Dengue fever is the most common arthropod
borne viral disease.
• Dengue fever is one of the most important
emerging disease of the tropical and sub
tropical regions, affecting urban and pre
urban areas.

6. Virus

7. Virsuses
Arboviruses
Bunyaviruses
All are mosquito borne
Sandfly fever
Rift valley fever
Cramean –Congo fever
Group A
Togaviruses
e.g. encephalitis
Group B
Togaviruses
By Mosquito
Yellow fever, Denque
fever
By Ticks
Russian fever
E. Spring Summer fever

8. The Dengue Virus
Four types :Has 4 serotypes (DEN-1, 2, 3, 4)
Causes dengue and dengue hemorrhagic
fever
• Is an arbovirus
• Transmitted by mosquitoes
• Composed of single-stranded RNA

9. Dengue Viruses
• Each serotype provides specific lifetime
immunity, and short-term cross-immunity
• All serotypes can cause severe and fatal
disease
• Genetic variation within serotypes
• Some genetic variants within each serotype
appear to be more virulent or have greater
epidemic potential

10. Dengue Symptoms
• Undifferentiated fever
• Classic dengue fever
• Dengue hemorrhagic fever
• Dengue shock syndrome

11. Undifferentiated Fever
• May be the most common manifestation of
dengue
• Prospective study found that 87% of
students infected were either asymptomatic
or only mildly symptomatic
• Other prospective studies including all age-
groups also demonstrate silent transmission
DS Burke, et al. A prospective study of dengue infections
in Bangkok. Am J Trop Med Hyg 1988; 38:172-80.

12. Clinical Characteristics
of Dengue Fever
• Fever
• Headache
• Muscle and joint pain
• Nausea/vomiting
• Rash
• Hemorrhagic manifestations

13. Hemorrhagic Manifestations
of Dengue
• Skin hemorrhages: ‫الجلد‬ ‫نزيف‬
petechiae, purpura, ecchymoses
• Gingival bleeding‫للثة‬ ‫نزيف‬
• Nasal bleeding‫لألنف‬ ‫نزيف‬
• Gastro-intestinal bleeding: ‫لألمعاء‬ ‫نزيف‬
hematemesis, melena,
• Hematuria
• Increased menstrual flow‫الطمث‬ ‫تدفق‬ ‫زيادة‬

14. Skin bleeds

15. Bleeding into the eye

16. Large bleed into skin

17. Clinical Case Definition for
Dengue Shock Syndrome
• Evidence of circulatory failure manifested
indirectly by all of the following:
– Rapid and weak pulse
– Narrow pulse pressure ( 20 mm Hg) OR
hypotension for age
– Cold, clammy skin and altered mental status
• Frank shock is direct evidence of circulatory
failure

18. Aedes Aegypti Mosquito

19. Incubation period
3-14 days (commonly 4-7 days)

20. Aedes Aegypti
• Dengue transmitted by infected female
mosquito
• Highly domesticated tropical mosquito.
• Prefer to lay eggs in artificial containers e.g.
flower vases, automobile tires…etc.
• Prefer to rest indoors.
• Prefer to feed on humans during daytime
hours.

21. Vector
• Aedes mosquitoes (Tiger mosquito):
distinguished by white stripes on black body.
• Important members Aedes family: Aedes .
Aegypty, Aedes.vittatus and Aedes. albopictus.
• They are most abundant during rainy season.

23. Vector
• Lays egg singly, and eggs are cigar shaped.
• Female mosquito acts as vector.
• They do not fly over long distance-
<100mts(110yards), this factor facilitates its
eradication.

24. World Distribution of Dengue 1999
Areas infested with Aedes aegypti
Areas with Aedes aegypti and recent epidemic dengue

25. Dengue fever in KSA
Year N. of suspected
cases
N. of confirmed
cases
1994
1995
1996
1997
1998
1999
2000
2001
2002
673
136
57
62
31
26
17
07
11
289
6
2
15
00
3
0
0
4
Total 1020 319

27. Rift Valley Fever cases
Dengue Fever cases
Year-wise
289
1994
6
1995
2
1996
15
1997
0
1998
3
1999
1328
0
2000
0
2001
4
2002
2003
2004
406
2005
1544
2006
490
2007
913
2008
0
3350
2009
0
3526
2010
2011

28. Vector and Transmission

29. Replication and Transmission
of Dengue Virus (Part 1)
1. Virus transmitted
to human in mosquito
saliva
2. Virus replicates
in target organs
3. Virus infects white
blood cells and
lymphatic tissues
4. Virus released and
circulates in blood
3
4
1
2

30. Replication and Transmission
of Dengue Virus (Part 2)
5. Second mosquito
ingests virus with blood
6. Virus replicates
in mosquito midgut
and other organs,
infects salivary
glands
7. Virus replicates
in salivary glands
6
7
5

31. Pathogenesis

In experimental studies of dengue virus infection in
rhesus monkeys, after subcutaneous inoculation,
virus was disseminated rapidly to regional lymph
nodes and then to lymphatic tissue through out the
body.

32. What are the tests needed?
 Routine blood test
 Tests to check the clotting process
 Special tests to identify the Dengue or its foot
marks in our blood
 Urine to check protein leak

33. Special Test (ELISA)
ELISA Plate IgM-capture ELISA

34. Treatment of Dengue
 Supportive measures – Mosquito screen
 Avoid Aspirin .
 Plenty of water and salt are required
 Children below 12 require careful watch
for dangerous form
 No antibiotics are of proven value

35. Prevention

36. Mosquito Control
How to prevent mosquito spread?
1. Frequently (once in 2-3 days) empty all water storage
containers
2. Cover your over tanks to prevent mosquitoes breeding
in fresh water
3. Do not allow empty vessels, coconut shells, plastic
containers, flower pots, tires etc to collect rain water in
them

37. How to prevent mosquito bites?
 Screen your homes with mosquito screens like
Netlon .
 Wear full clothing – long sleeves.
 Apply mosquito repellents like Odomos.
 Keep Dengue fever patient under mosquito net.
 True community participation is key.

38. Thank you