TOPIC: DENGUE FEVER IN

MALAYSIA &

HOW DO WE DEAL WITH IT

OUR AIMS

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

CHAPTER 1: DENGUE FEVER IN

GENERAL

What will we learn throughout the CHAPTER 1?

CHAPTER 1: DENGUE FEVER IN GENERAL

i. DEFINITIONii. THE INFECTIOUS AGENTiii. THE HOST & CARRIERSiv. LIFE CYCLEv. CLINICAL PICTUREvi. HISTOPATHOLOGY

CHAPTER 1: DENGUE FEVER IN GENERAL

i- DEFINITION

What is dengue fever?

It is a fever associated with other significance of clinical manifestations caused by virus from mosquito bite

How is dengue spread?

• Dengue fever is not contagious.

• It cannot be spread directly from one person to another person.

• The mosquito transmits the disease by biting an infected person and then biting someone else.

Aedes aegypti

Aedes albopictus

Aedes larvae

CHAPTER 1: DENGUE FEVER IN GENERAL

ii- THE INFECTIOUS AGENTWhat 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

CHAPTER 1: DENGUE FEVER IN GENERAL

iii- THE HOST & CARRIERSThe host: Unfortunately, human is the only

hostCarriers: 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

Aedes aegypti

Aedes albopictus

CHAPTER 1: DENGUE FEVER IN GENERAL

iv- THE CYCLE

Transmission Cycle of Dengue Virus

Transmission Cycle of Dengue Virus

Life cycle of the vector

To The Left, The Male, In The Middle And On The Right, The Female. Above Left, A Flying

Pair In Copula.

CHAPTER 1: DENGUE FEVER IN GENERAL

v- CLINICAL PICTURE 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.

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.

Are there many clinical types of dengue? YES.

3 Phases of The Disease

Maculopapular rash

Note that dengue fever symptoms usually refers to various symptoms known to a patient, but the phrase

dengue fever signs may refer to those signs only noticeable by a doctor.

High fever - up to 105 degrees Fahrenheit (40.56 Celsius )

Severe headache Retro-orbital pain -

pain behind the eye Severe joint pains Muscle pains Muscle aches Swollen lymph nodes General weakness Nausea Vomiting

Children get non-typical symptoms

Fever Weakness Prostration - physically

& emotionally weak Severe headache Severe muscle pain Slowed heart rate Enlarge lymph nodes Maculopapular rash Rash

WHAT IS DENGUE HEMORRHAGIC FEVER?

Dengue hemorrhagic fever is a severe, often fatal, complication of

dengue fever.This is the most feared condition to us

WHO definition of dengue haemorrhagic fever

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)

There are three phases of dengue haemorrhagic fever:

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.

CHAPTER 1: DENGUE FEVER IN GENERAL

vi: HISTOPATHOLOGY

•A TEM micrograph showing dengue virus virions

(the cluster of dark dots near the center)

Reference

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=Immunopathological%20mechanisms%20in%20dengue%20and%20dengue%20hemorrhagic%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)