DENGUE(pronounced DENgee)

SUHAILI BINTI SAHIFUL BAHARI

INDEX

• Pathogenesis• Epidemiology• Epidemiological

Determinant– Causative agent– Host– Environmental factor

• Route of transmission– Mode– Incubation period

• Clinical features– Febrile phase– Critical phase– Recovery phase

• Complication• Prevention

Pathogenesis.

• Attacking immune system– Injected into bloodstream – > viremia (high amount of virus in the blood

after 4 days being bit)– > infect of inmature Langerhans cells and

keratinocytes – > infected cells migrate to LN where

monocytes & macrophages recruited – > infection amplified – > virus into lymphatic system.

Epidemiology

• 1998: Pandemic attack at 56 countries.• Fatalities double among children at South

East Asia Region (SEAR).• Endemic at SEAR countries: Bangladesh,

India, Indonesia, Maldives, Myammar, Sri Lanka, and Thailand ~ 1.3 billion living people.

• Tropical and subtropical regions affecting urban and periurban areas.

Epidemiological Determinant

1.Causative agent– Aedes aegypti and– Aedes albopictus

3.Environmental factor– Urban place– Uncontrolled population growth without

appropriate water management.

2.Host– Human. All age.– More likely to occur in persons who have recently

traveled to affected areas.

Route of transmission.

Incubation period is begin 4 - 7 days after the mosquito bite and typically last 3 - 10 days.

1.Mosquitoes sucks blood from infected person.

2.Mosquitoes now carry the dengue virus.

3.Mosquitoes keep on sucking blood and spread the virus to another healthy person.

Mode: Communicable disease (Vector)

Clinical features

• 2 types of Dengue virus infection:– Asymptomatic: No sign and symptoms.– Symptomatic:

• Undifferentiated (viral syndrome)• Dengue fever (DF):

–Without haemorrhage–With haemorrhage

• Dengue haemorrhagic fever (DHF):–No shock.(plasma leakage)–Dengue shock syndrome (DSS)

Febrile phase:Undifferentiated

• first clinical course

• benign scenario

• mild fever

• mimic acute febrile illness

• recover fully without need for hospital care.

Febrile phase: Dengue fever (DF)(with/without haemorrhage.)

• second clinical course• 2-7 days of high fever.• two or more of the following symptoms:

severe headache, retro-orbital eye pain, myalgias, arthralgias, a diffuse erythematous maculo-papular rash, and mild hemorrhagic manifestation.

• nausea and vomiting in children.• do not develop substantial plasma leak.

Critical phase: Dengue haemorrhagic fever (DHF) <48 h

• Plasma leakage /No shock– Watch evidence of

hemorrhage and plasma leak into the pleural and abdominal cavities (Liver enlargement (≥2cm))

– intravascular volume depletion– cardiovascular compromise– sudden increase in hematocrit

(≥20%)– Abdominal pain or tenderness– Persistent vomiting– Clinical fluid accumulation

(i.e., pleural effusion or ascites)

– Mucosal bleeding

• Dengue Shock Syndrome (DSS)

– Absence of fever.– Weak– Tachycardia, thready

pulse– Cool extremities– Narrowing pulse

pressure.– Delayed capillary refill– Oliguria

Convalescent (Reabsorption) or Recovery Phase:

• Plasma leak stops and reabsorption begins.

• Return of appetite• Stabilizing vital signs (widen pulse

pressure, strong palpable pulse)• Bradycardia• Hematocrit levels returning to normal.• Increased urine output.

Complications

• Hypocalcemia

• Hypoglycemia

• Hyperglycemia

• Lactic acidosis

• Hyponatremia

• All are frequently related to prolonged shock.

Prevention• Do not travel or visit affected areas.• Empty stagnant water from old tires, trash cans, and flower pots. (Reduce

mosquito habitat.)• Stay in air-conditioned or well-screened housing.• Reschedule outdoor activities. (Mozzie attacks on daylight - before dust.)• Wear protective clothing. • Use mosquito repellent. • More vector control programme.• More DDT? :(

– An insecticide used in agriculture.– Adverse effect bird reproduction.– Effect on respiratory system permanently if stay for long time- causing premature

birth among human.– Disturb ecosystem - kills aedes's predators which is bigger and wilder mozzies– Jeopardizing public health.