Presentation for Research & Student Activities in our Urosurgery Round

2.  To discuss about dengue fever in general; the
host, the infectious agent, their types and life
cycles and method of transmission
 To explain why this topic is very important for
us, Malaysian, the Asian community
 To discuss the impact of this disease to our
environment, community, socioeconomic
 And how we deal with it specifically and
generally

3. CHAPTER 1:
DENGUE FEVER IN
GENERAL

4. CHAPTER 1: DENGUE FEVER IN GENERAL
i. DEFINITION
ii. THE INFECTIOUS AGENT
iii. THE HOST & CARRIERS
iv. LIFE CYCLE
v. CLINICAL PICTURE
vi. HISTOPATHOLOGY

5. What is dengue fever?
 It is a fever associated with other significance
of clinical manifestations caused by virus from
mosquito bite

6. • Dengue fever is not contagious.
• It cannot be spread directly from
one person to another person.
• The mosquito transmits the Aedes aegypti
disease by biting an infected
person and then biting someone
else.
Aedes albopictus
Aedes larvae

7. What are the infectious agent?
• Dengue Fever and dengue
hemorrhagic fever are caused
by any of the dengue family
of viruses.
• Infection with one virus does
not protect a person against
infection with another. This is
due to 4 strains or serotypes
of dengue virus namely
• DEN-1
• DEN-2
• DEN-3
• DEN-4

8. The host: Unfortunately, human is the only host
Carriers: Mosquito, Aedes species.
 Aedes aegypti - yellow fever mosquito
 Bites man, carries chikungunya, dengue fever,
heartworm, Murray Valley encephalitis, Ross River
virus, West Nile virus, yellow fever
 Aedes albopictus - Asian tiger mosquito
 Bites man, carries Cache Valley virus, chikungunya,
dengue fever, Eastern equine encephalitis, West Nile
virus

12. Transmission Cycle of Dengue Virus

17.  How soon after exposure do symptoms
appear?
• The time between the bite of a mosquito carrying
dengue virus and the start of symptoms averages 4 to 6
days, with a range of 3 to 14 days.
• An infected person
cannot spread the
infection to other persons
but can be a source of
dengue virus for
mosquitoes for about 6
days.

18. Are there many clinical types of dengue? YES.
Classic picture is :
• high fever with no localizing source of infection
• a petechial rash with thrombocytopenia
• relative leukopenia - low platelet and white blood cell count.
Dengue hemorrhagic fever is:
• General: Fever, bladder problem, constant headaches, severe
dizziness and loss of appetite.
• Hemorrhagic tendency
• Thrombocytopenia
• Evidence of plasma leakage
Dengue shock syndrome is defined as dengue hemorrhagic fever
plus:
• Weak rapid pulse,
• Narrow pulse pressure (less than 20 mm Hg)
• Cold, clammy skin and restlessness.

21.  High fever - up to 105  Children get non-typical
degrees Fahrenheit (40.56 symptoms
Celsius )  Fever
 Severe headache  Weakness
 Retro-orbital pain - pain  Prostration - physically &
behind the eye emotionally weak
 Severe joint pains  Severe headache
 Muscle pains  Severe muscle pain
 Muscle aches  Slowed heart rate
 Swollen lymph nodes  Enlarge lymph nodes
 General weakness  Maculopapular rash
 Nausea  Rash
 Vomiting

22. Dengue hemorrhagic fever is a severe,
often fatal, complication of dengue
fever.
This is the most feared condition to us

23. The has been in use since 1975; all four criteria must be fulfilled:
 General: Fever, bladder problem, constant headaches, severe dizziness and
loss of appetite.
 Hemorrhagic tendency (positive tourniquet test, spontaneous bruising,
bleeding from mucosa, gingiva, injection sites, etc.; vomiting blood, or bloody
diarrhea)
 Thrombocytopenia (<100,000 platelets per mm³ or estimated as less than 3
platelets per high power field)
 Evidence of plasma leakage (hematocrit more than 20% higher than expected,
or drop in haematocrit of 20% or more from baseline following IV fluid,
pleural effusion, ascites, hypoproteinemia)

25.  The first is the febrile phase. This phase is defined
by very high body temperature of 40-41°C, and
obvious feverish facial flush, vomiting, abdominal
pain or restlessness.
 The second is the plasma leakage phase. This phase
starts at the end of the febrile phase, with the body
temperature drops below 38°C. This phase lasts for
24 to 48 hours. This is also known as the critical
phase.
 The third is the re-absorption or convalescent phase
where plasma that leaks is reabsorbed. At this phase
the patient may experience respiratory distress or
difficulty in breathing.

26. •A TEM micrograph
showing dengue
virus virions
(the cluster of dark
dots near the center)

27.  http://en.wikipedia.org/wiki/Dengue (Wikipedia)
 http://www.denguedb.org/index.asp?bhcp=1
 http://www.aegis.com/aidsline/1997/jun/M9761120.html
 http://www.nlm.nih.gov/cgi/mesh/2008/MB_cgi?mode=&term=Dengue&field=
entry#TreeC02.782.417.214
 http://www.searo.who.int/en/Section10/Section332/Section1985_9808.htm
(WHO)
 http://emedicine.medscape.com/article/215840-print
 http://health.state.ga.us/pdfs/epi/vbd/DengueFAQ.pdf
 http://www.nlm.nih.gov/medlineplus/dengue.html (MedlinePlus)
 http://www.plosntds.org/article/findArticle.action?author=Green&title=Immun
opathological%20mechanisms%20in%20dengue%20and%20dengue%20hemorrhag
ic%20fever. (Public Library of Science : Neglected Tropical Diseases)
 http://library.thinkquest.org/07aug/01614/treatment.html
 http://library.thinkquest.org/07aug/01614/dengue-malaysia.html
 http://library.thinkquest.org/07aug/01614/symptoms.html
 http://jvi.asm.org/cgi/content/abstract/76/23/12242 (Journal of Virology)
 http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid
=9665979 (PubMed Central)