Dengue

• the most common arboviral illness transmitted worldwide
• is an acute febrile disease caused by the dengue single-stranded RNA flavivarus
• It is spread by Aedes eagypti mosquito 
• it  is manifested by a sudden onset of fever, with severe headache, muscle and joint and rashes 
• it is most common in tropical countries and Africa 
• it occurs in over 100 countries, with more than 2.5 billion people at risk and an estimated 50 million infection per year

2 types of dengue:

1.      Dengue fever 

•  is more severe in adults in which incapacitating muscle, joint and bone pain ("break-bone fever') are common. 
• is known as a non-fatal or rarely fatal disease

2.      Dengue Hemorrhagic Fever

• occurs mostly in children under the age of 16 year 
• is characterized by signature features of thrombocytopenia (low platelet count) and vascular leakage 
• is associated with mortality because of its tendency to develop into a fatal shock (Dengue Shock Syndrome; sever form of DHF)

 (DSS- is defined as DHF with weak rapid pulse, cold clammy skin, and restlessness)

Etiology

Etiologic Agent

• Dengue Virus Type 1,2,3,4 and Chikungunya virus

Source of infection

• Aedes Aegypti
• Infected Person

Mode of transmission 

• Mosquito bite (aedies Aegypti)

Pathophysiology

Incubation period: 

• Uncertain. Probably 6 dys to one week

Period of Communicability: 

• Unknown. Presumed to be on the first week of illness - when virus is present in the blood.

 

Diagnosis

• Tourniquet Test
• Inflate the BP cuff to a point midway between the systolic and diastolic pressure for 5 mins
• Release the cuff and make an imaginary 2.5 cm or 1 inch square just below the cuff, at the antecubital fossa

Count the number if petechiea insde the box, a test is (+) when 20 or more petechiae are observed

•    Complete Blood Count (CBC)

o       Platelet count is below 150,000 and 450,000 per mm³

Signs and Symptoms

• First 4 days,
• Febrile or high fever
• Abdominal pain and headache
• Flushing that maybe accompanied by vomiting , conjuctival infection and epistaxis

• 4^th – 7^th days (toxic or hemorrhagic stage)
• Lowering of temperature
• Severe abdominal pain
• Vomiting and frequent bleeding from GI tract (hematemesis or melena)
• Unstable BP
• Narrow pulse pressure and shock
• Tourniquet test which is (+) on the 3^rd day may become (-) due to low platet count
• Death may occur

• 7^th – 10^th days,
• Recovery stage

Classification 

• Severe,

• With flushing, sudden high fever, severe hemorrhage, sudden drop of temperature, shock and terminating in recovery or death
• Moderate
• High fever, but less hemmorhage, no shock
• Mild,
• Slight fever, w/ or w/o hemmorhage

Treatment

• Supportive and symptomatic treatment should be provided
• For fever, give paracetamol for muscle pains
• For headache, give analgesic. DON’t give ASPIRIN (anticoagulant)
• Increase oral fluid intake to prevent dehydration
• Give ORESOL to replace fluid as in moderate dehydration

Nursing Mgt

• For hemorrhage,
• Keep patient in Complete Bed Rest (CBR)
• For  Epistaxis, place patient in High Fowlers position and place ice bag over the head
• For Melena (GI bleeding), place ice bag over the abdomen
• Instruct the patient to avoid unnecessary movements
• If transfusion is given, support the patient during therapy
• Observe signs of deterioration that can lead to DSS

• For Shock,
• Prevention is the best treatment
• Place the patient in a Dorsal Recumbent Position to facilitate circulation
• Adequate preparation of the patient, mentally and physically prevents the occurrence of shock
• Provide heat through lightweight covers.

• Diet,
• Low fat, low fiber, non-irritating, non-carbonated.
• Noodle soup may be given.

Fast facts about the mosquito

Aedes Eagypti Mosquito

• Only the female aedes mosquito bites as it needs the protein in blood to develop its eggs.
• The mosquito becomes infective approximately 7 days after it has bitten a person carrying the virus. This is the extrinsic incubation period, during which time the virus replicates in the mosquito and reaches the salivary glands.
• Peak biting is at dawn and dusk.
• The average lifespan of an Aedes mosquito in Nature is 2 weeks
• The mosquito can lay eggs about 3 times in its lifetime, and about 100 eggs are produced each time. 
• The eggs can lie dormant in dry conditions for up to about 9 months, after which they can hatch if exposed to favourable conditions, i.e. water and food