DENGUEPrepared by:

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Dengue Dengue virus (RNA Virus), flavivirus,

Arbovirus (arthropod borne virus) May lead to – Classical dengue fever Dengue hemorrhagic fever without shock Dengue hemorrhagic fever with shock

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Dengue fever is self limiting Prevalence of Aedes aegypti and Aedes

albopictus together with circulation of dengue virus of more than one type in any particular area tends to be associated with outbreaks of DHF/DSS

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It is most common among arthropod borne viral diseases

One of the most important emerging disease of tropical and sub tropical regions, affecting urban and peri urban areas

50 million infections; 500,000 cases of DHF; 12000 deaths.

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Endemic in Bangladesh, India, Indonesia, Maldives, Myanmar, Srilanka and Thailand.

Among 4 subtypes DEN-2, DEN-3 reported in Bangladesh and Maldives.

In SEA region, next to diarrhoeal disease and ARI, leading cause of hospitalization and deaths among children.

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SEAR counties-

Category A (Indonesia, Myanmar, Thailand- major PH problem)

Category B (India, Bangladesh, Maldives, Srilanka- emerging disease, cyclical epidemics)

Category C (Nepal, Bhutan- no reported cases, endemicity uncertain)

Category D (DPR Korea, non endemic)

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Classical Dengue Fever

‘Break bone fever’, acute viral infection Caused by 4 serotypes (1, 2, 3, 4) of

dengue virus. Epidemics are explosive and often start

during rainy season, low in lower temperature (below 26°c).

Reservoir – man and mosquito

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Aedes aegypti is the main vector. Becomes infective by feeding on a patient from the day before onset to the 5th day (viraemia stage) of illness. After an extrinsic incubation period of 8-10 days, the mosquito becomes infective and able to transmit the infection for life long.

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Clinical features:

IP 5-6 days. Onset is sudden with chills and high fever, intense headache, muscle and joint pains which prevent all movements.

Within 24 hours- retro orbital pain on eye movement or eye pressure develops photophobia.

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Extreme weakness, anorexia, constipation, altered taste sensation, colicky pain and abdominal tenderness, dragging pain in inguinal region, sore throat, general depression.

Tempearture-102° to 104°. Fever is typically followed by a remission of a few hours to 2 days (biphasic curve).

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Rash appears during remission or during 2nd febrile phase. Rash- diffuse, flushing, mottling or fleeting pin point eruptions on the face, neck or chest. Rash lasts for 2 hours to several days and may be followed by desquamation.

Fever lasts for 5 days, rarely exceeds 7 days.

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Dengue Hemorrhagic fever

Severe form of Dengue, caused by infection with more than one dengue virus. Transmitted by A. aegypti.

Double infection with dengue virus; first infection probably sensitizes the patient, second produces immunological catastrophe

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IP: 4-6 days, abrupt onset with high fever accompanied by facial flushing, headache, anorexia, vomiting, epigastric discomfort, tenderness at the right costal margin and generalized abdominal pain. Rash less common during first few days which resembles classical dengue fever. May appear late in illness.

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Temperature 104-105°F, febrile convulsion in infants.

Plasma leakage, abnormal hemostasis; manifested by increased hematocrit value and moderate to marked thrombocytopenia.

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Clinical diagnosis: Fever-acute onset, high,

continuous, lasting for 2-7 days. Hemorrhagic manifestations-

positive tourniquet test (more than 20 petechiae per 2.5 cm² (Petechiae, purpura, echymosis, epistaxis, gum bleeding, haematemesis and/or malaena)

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Grading of severity of DHF:

Grade I: Fever accompanied by non specific constitutional symptoms. Only hemorrhagic manifestation is a positive tourniquet test.

Grade II: Spontaneous bleeding in the form of skin and/or other hemorrhages+ manifestations of grade 1.

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Grade III: Circulatory failure manifested by rapid and weak pulse, narrowing of pulse pressure (20 mmHg/ less) or hypotension with the presence of cold, clammy skin and restlessness.

Grade IV: Profound shock with undetectable BP and pulse.

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Laboratory diagnosis:

Thrombocytopenia (100,000/mm³ or less)

Hemoconcentration; hematocrit is increased by 20% or more of baseline value.

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Dengue Shock Syndrome: All above criteria plus shock manifested by rapid and weak pulse with narrowing of pulse pressure or hypotension with the presence of cold, clammy skin and restlessness.

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Treatment: Management is symptomatic and

supportive. Bed rest in acute febrile phase. Antipyretic and sponging. Aspirin should be avoided particularly in areas where DHF is endemic, since it may cause gastritis, bleeding and acidosis. Oral fluid and electrolyte therapy in excessive sweating, vomiting and diarrhoea.

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Management of DHF- during febrile phase similar to DF. Increased hematocrit indicates significant plasma loss and need for parenteral fluid therapy. In grade I and II, volume replacement can be given in 12-24 hours. Patient with signs of bleeding and persistently increased hematocrit should be admitted to hospital.

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Volume and type of fluid similar to diarrhoea with moderate isotonic dehydration.

Hct determination at every 4-6 hours and recording of vital signs.

Fluid used- 5% Dextrose in Ringers lactate solution.

Management of shock

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Control measures for Dengue

• Control or eradication of the mosquitoes carrying the virus that

causes dengue.

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To prevent mosquito bites, wear long-sleeved shirts, long pants, socks and shoes when outdoors.

Install mosquito screens on windows

For personal protection, use mosquito repellant sprays that contain DEET when visiting places where dengue is endemic.

They bite during early morning hours, before day break and in the late afternoon before dark.

Cover overhead tank to prevent access

Eliminate stagnant water at home, workplaces and their vicinity.

Eliminate breeding sources (unused plastic pools, old tires, or buckets and clearing clogged gutters)

Use citronella oil-based creams and sprays or other mosquito repellents

Replace water in flower vases once a week