Dengue

Group: Group IV ((+)ssRNA)
Family: Flaviviridae
Genus: Flavivirus
Species: Dengue virus

• Dengue (DF) and dengue hemorrhagic fever (DHF) are caused by one of four closely related, but antigenically distinct, virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4), of the genus Flavivirus.
• Infection with one serotype does not protect a person against infection with another.
• Aedes aegypti, a domestic, day-biting mosquito that prefers to feed on humans, is the most common Aedes species.(Unlike the mosquitoes that cause malaria, dengue mosquitoes bite during the day.)
• Dengue viruses occur in most tropical areas of the world.
• Dengue is most common in cities but can be found in rural areas.
• Incubation Period: averages 4 to 6 days, with a range of 3 to 14 days.

• High fever, up to 105 degrees Fahrenheit
• Severe headache
• Retro-orbital (behind the eye) pain
• Severe joint and muscle pain
• Nausea and vomiting
• Rash

The rash may appear over most of your body 3 to 4 days after the fever begins.

Symptoms of dengue hemorrhagic fever include all of the symptoms of classic dengue plus

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

1. Fever
2. Haemorrhagic tendency (positive tourniquet test, spontaneous bruising, bleeding from mucosa, gingiva, injection sites, etc.; vomiting blood, or bloody diarrhea)
3. Thrombocytopaenia (<100>
4. Evidence of plasma leakage (hematocrit more than 20% higher than expected, or drop in haematocrit of 20% or more from baseline following IV fluid, pleural effusion, ascites, hypoproteinaemia)

1. Weak rapid pulse,
2. Narrow pulse pressure (less than 20 mm Hg)
   

1. Hypotension for age;
2. Cold, clammy skin and restlessness.
   

Category: Medicine Notes , Microbiology Notes