Bs(Hons.), Final Semester
Bs (Hons.), Final Semester
Endemic in more than
100 tropical and
Several epidemics since
Pandemic began in
South East Asia after
WW II with subsequent
The word dengue is derived from African word Denga:
meaning fever with hemorrhage .
Is caused by virus transmitted by bites of female
Dengue is a viral disease.
It is caused by infective bite of female Aedes aegypti.
Man develops disease after 5-6 days of being bitten by
Dengue fever is a severe flu like illness.
Dengue Hemorrhagic fever (DHF) is more severe form
of disease which can cause death.
1.Causes dengue and
2. It is an arbovirus
5.Has 4 serotypes
(DEN-1, 2, 3, 4)
The most common epidemic vector of dengue in the
world is the Aedes aegypti mosquito. It can be
identified by the white bands or scale patterns on its
legs and thorax.
• Dengue transmitted by infected female mosquito
• Primarily a daytime feeder
• Lives around human habitation
Clean and stagnant water collections
Breed mostly around human dwellings and
Lays eggs and produces larvae preferentially in
Aedes mosquitoes (Tiger mosquito): distinguished by
white stripes on black body.
Important members Aedes family:A. aegypti,
A.vittatus and A. albopictus.
They are most abundant during rainy season.
Lays egg singly, and eggs are cigar shaped.
Female mosquito acts as vector.
They do not fly over long distance- this factor
facilitates its eradication.
It is a day biter
High continuous fever lasting for 2-7 days.
Severe and continuous pain in abdomen
Bleeding from the nose, mouth and gums or skin
Frequent vomiting with or without blood
Excessive thirst (dry mouth)
Pale, cold skin
Restlessness, or sleepiness
1.The virus is inoculated into humans with the
2.The virus localizes and replicates in various
target organs, for example, local lymph nodes and
3.The virus is then released from these tissues and
spreads through the blood to infect white blood
cells and other lymphatic tissues.
4.The virus is then released from these tissues and
circulates in the blood.
5.The mosquito ingests blood containing the virus.
6.The virus replicates in the mosquito midgut, the ovaries,
nerve tissue and fat body. It then escapes into the body
cavity, and later infects the salivary glands.
7.The virus replicates in the salivary glands and when the
mosquito bites another human, the cycle continues.
In most tropical areas Ae. aegypti is highly urbanized.
They breed in fresh water like water stored for drinking
or bathing and in rain water collected in any container
like tires etc.
Dengue viruses have also been recovered from Aedes-
Outbreaks in the Pacific area have been attributed to
several other Aedes species.
These species breed in water trapped in vegetation
Mosquito control or eradication programs
require the simultaneous use of two
Reduction in breeding sites
Application of larvicides
Alternatively, a significant reduction in
population may be effected by closely spaced
application of adulticides
Source reduction campaigns should be well organized,
supervised, and evaluated.
Includes proper disposal of discarded cans, bottles,
tires, and other potential breeding sites not used for
storage of drinking or bathing water.
Drinking and bathing water storage containers and
flower vases should be emptied completely once
Most dengue cases are mild with flu like illness which
can be treated and cured so no need to be panic.
Dengue id detected with Igm ELISA based test.
There is no specific medicine to treat dengue infection.
To reduce pain use of pain relievers with acetaminophen
and avoid medicines with aspirin, which could worsen
Rest, drink plenty of fluids.
In case of Dengue Hemorrhagic fever hospitalization is a
must. The mortality rate in the absence of hospitalization
can be as high as 50%. With proper treatment the mortality
comes down to 3%.
Vaccines are being developed against all 4 serotypes and
they will definitely be the most effective way to prevent the