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Dengue fever (DF) Is an acute febrile viral illness presenting with

headache , bone or joint and muscular pains , rash and leukopenia caused by arthropod – borne viruses.

Dengue hemorrhagic fever ( DHF ) : - Is characterized by four major manifestations : High grade fever , hemorrhagic phenomenon Hepatomegaly Signs of circulatory failure

Dengue shock syndrome (DSS ) : - Hypovolemic shock resulting from plasma leakage

Dengue Dengue is mosquito-borne infection transmitted by

the bite of an Aedes mosquito Symptoms appear 3-14 days after the infective bite. Symptoms range from a mild fever to high fever, with

severe headache, pain behind the eyes, muscle and joint pain, and rash.

Epidemiological features Agent factors:

Agent: The dengue viruses are arthropod-borne viruses of the Flavivirus genus, within the family Flaviviridae. There are four serologically distinct dengue virus serotypes (DEN-1, DEN-2; DEN-3 and DEN-4)

Reservoir of infection: Humans are the main amplifying host of the virus.

Host factors: All ages and both sexes are susceptible to dengue fever.

Cont.. Environmental factors: Start during rainy season

when the breeding of the vector mosquito is generally abundant.

Modes of transmission It is transmitted by the bite of an infected female

Aedes species mosquito. Worldwide, Aedes aegypti, a day-biting species, is the major vector for human-to-human transmission .

Incubation period: 8-10 days

Clinical features (three forms): -Classical dengue fever

Symptoms of typical uncomplicated (classic) dengue usually start with fever within 4 to 7 days after bite by an infected mosquito and include

High fever, up to 105ºF Severe headache Retro-orbital (behind the eye) pain Severe joint and muscle pain Nausea and vomiting Rash: may appear over most of the body 3 to 4 days

after the fever begins, and then subsides after 1 to 2 days.

Prolonged fatigue and depression are typical symptoms during the recovery phase.

Dengue hemorrhagic fever

Fever: acute onset, high, continuous, and lasting for 2-7 days.

Marked damage to blood and lymph vessels Bleeding from the nose, gums, or under the skin,

causing purplish bruises. Haemorrhagic manifestation including petechia,

purpura, ecchymosis, epistaxis, gum bleeding, haematemesis and malena

The liver is often enlarged. This form of dengue disease can cause death.

Grading of severity of DHF

Grade I: the only haemorrhagic manifestation is a positive tourniquet test.

Grade II: Patients with spontaneous bleeding Grade III: Circulatory failure manifested by rapid and

weak pulse, low blood pressure, with presence of cold and clammy skin and restlessness.

Grade IV: Profound shock with undetectable blood pressure and pulse

Dengue shock syndrome- The most severe form of dengue disease, include

all of the symptoms of classic dengue and dengue hemorrhagic fever, plus

Massive bleeding Shock This form of the disease usually occurs in children

(sometimes adults) experiencing their second dengue infection. It is sometimes fatal, especially in children and young adults.

Diagnosis

From symptoms. Positive tourniquet test. Blood test: Thrombocytopenia Haemoconcentration, haemotocrit increased by

20%. During 3-7 days of illness, the virus can be isolated

from blood/serum. From 8th day, specific antibodies can be detected by serological tests.

Clinical criteria to hospitalize with DF Severe abdominal pain Passage of black stool Bleeding into the skin or from the nose or

gums Sweating Cold skin

Treatment

The management of dengue fever is symptomatic and supportive, including careful management of fever, bed rest, fluid balance, electrolytes and clotting parameters, is crucial for the case management of dengue hemorrhagic fever.

It is important to maintain hydration. Avoid aspirin. Dengue haemorrhagic fever is a potentially lethal

complication, affecting mainly children. Early clinical diagnosis and careful clinical management by experienced physicians and nurses increase survival of patients.

Prevention Personal protective measures are aimed

at preventing mosquito bites during the day,

particularly early morning and late afternoon. use personal insect repellents use insecticide mats to kill mosquitoes screen living and sleeping areas wear long, loose clothing when outdoors spray indoors in dark places (eg.behind

cupboards, under beds)

Cont..

The best form to control is to get rid of dengue mosquito breeding sites around the home.

Dengue mosquitoes breed in containers that hold water.

These include buckets, tyres, pot plant bases Roof guttering, rainwater tanks are also potential

breeding sites.

Recommendations to control breeding include: tipping out containers which can hold water storing containers in a dry place throwing out rubbish that collects water