dengue, dengue fever

 ALTERNATIVE NAMES :

▪ Haemorrhagic dengue

▪ Dengue shock syndrome

▪ Philippine haemorrhagic fever

▪ Thai haemorrhagic fever

▪ Singapore haemorrhagic fever

Dengue Haemorrhagic fever is an acute infectious viral disease usually affecting infants and young children. This disease used to be called break-bone fever because it sometimes causes severe joint and muscle pain that feels like bones are breaking.

▪ It is a severe, potentially deadly infection spread by certain species of mosquitoes (Aedes aegypti)

▪ Philippine haemorrhagic fever was first reported in 1953. in 1958 haemorrhagic fever became a notifiable disease in the country and was later reclassified as Dengue haemorrhagic fever.

SIGNS AND SYPTOMS :

▪ An acute febrile infection of sudden onset with clinical manifestation of 3 stages :

▪ First 4 days – Febrile or Invasive stage : high fever; abdominal pain and headache; later flushing which may accompanied by vomiting, conjunctival infection and epistaxis (bleeding from the nose).

▪ 4th – 7th days – Toxic or Haemorrhagic stage : lowering of temperature; severe abdominal pain; vomiting and frequent bleeding from gastrointestinal tract in the form of haematemesis (vomiting of stomach contents mixed with blood) or melena; unstable blood pressure; narrow pulse pressure; shock

▪ 7th – 10th day – Convalescent / recovery stage : generalized flushing with intervening areas of blanching appetite (digestion becoming regular) regained; blood pressure becoming stable.

Classification :

▪ Severe, frank type : with flushing, sudden high fever, severe haemorrhage, followed by sudden drop of temperature, shock and terminating in recovery or death.

▪ Moderate : with high fever, but less haemorrhage, no shock.

▪ Mild : with slight fever, with or without petenchial (red / purple spot) haemorrhage but epidemiologically related to typical cases usually discovered in the course of investigation of typical cases.

ETIOLOGIC AGENT :

▪ Flavivirus, dengue virus type 1,2,3, & 4

▪ Chikungunya virus

SOURCE OF INFECTION :

▪ Vector mosquito : Aedis aegypti; Aedis albopictus

▪ The infected person

▪ INCUBATION PERIOD :

▪ Uncertain : from 6 days to 7 days

▪ PERIOD FOR COMMUNICABILITY :

▪ Unknown. Presumed to be an the first week of illness when virus is still present in the blood.

EXAMS AND TESTS :

▪ Physical examination may reveal the following : low blood pressure; a weak & rapid pulse; rashes; red eyes; red throat; swollen glands; enlarged liver (haepatomegaly)

▪ Tests include : haematocrit (ratio of the volume of rbc to the total volume of blood); platelet count; electolytes; coagulation studies; liver enzymes; blood gases; tourniquet(device for stopping the flow of blood through a vein/artery) test ( causes petechiae below the tourniquet); x-ray of the chest; serologic studies; serum studies from samples taken during acute illness and convalescence (high in titre to dengue antigen)

METHODS OF PREVENTION AND CONTROL :

▪ The infected individual, contacts and environment :

▪ Recognition of the disease; isolation of patient; epidemiological investigation; case finding and reporting; health education.

Control Measures :

▪ Eliminate the vector by : changing water and scrubbing sides of lower vases once a week; destroy breeding places of mosquito by cleaning surroundings; proper disposal of rubber tyres, empty bottles, & cans.

▪ Avoid too many hanging clothes inside the house

▪ Residual spraying with insecticides

    

Video by Ravi Kant from Pexels