Dengue fever is a disease caused by a family of viruses that are transmitted by mosquitos. This disease has been found severe in areas of south east pacific and south east asia. Dengue fever is caused by an RNA containing virus of icosahedral symmetry. The virus capsid is enveloped.

2. Dengue fever
• Dengue fever is a disease caused by a family of viruses that are transmitted
by mosquitos.
• This disease has been found severe in areas of south east pacific and south
east asia.
• Dengue fever is caused by an RNA containing virus of icosahedral
symmetry. The virus capsid is enveloped.

3. Symptoms
 1)High fever
 2)severe abdominal pain
 3)vomiting
 4)decreased urination
 5)joint pain
 6)pain on eye movement
 7)head ache and body ache
 8)decrease in platelet count in bloo
 9)Bleeding

5.  Dengue fever is transmitted by a mosquito Aedes aegypti. It is commonly
known as Tiger mosquito.
 The aedes that lays egg in clean and stagnant water collections over hard
surfaces. The hard surfaces include tires, buckets, bird baths, water storage
jar and flower spots.

7. Life cycle of Ades aegypty
 Ades aegypti is called holometabolous insect. That is the insects goes through a
complete metamorphosis with an egg, pupae and adult stage.
 The life cycle of Aedes aegypti can be completed with one-and-a half to three
weeks.

9. Egg
 After taking a blood meal, the female Aedes aegypti mosquitos produce on
average 100 to 200 eggs per batch.
 The number of egg is dependent on the size of the blood meal.
 The eggs are laid on damp surfaces, tree holes and man made containers.
 Depending on the availability of suitable substratum the laid eggs over hours or
days.
 The eggs of Aedes aegypti are smooth & one mm long.
 When first eggs are laid they appear white. Within minutes they become shiny
black colour.
 In warm climates the laid eggs development take up to 2 days.
 In cooler temperate climates the laid eggs development take up to a week.

10. Larvae
 After hatching off the eggs, the larvae feed on the organic patter in the water such
as algae and other microscopic organisms.
 Most of the larval stage is spent at the water surface. If we disturbed the will swim
to the bottom of the container.
 Larval development is temperature dependent.
 The larvae pass through four instars, spending short amount of time in the first
three and up to 3 days in the fourth instar.
 Fourth instar larvae are approximately eight millimeters long.
 Males develops faster than females. So male generally pupate earlier

11. Pupae
 After the fourth instar, the larvae enters the pupal stage.
 Mosquito pupae are mobile and respond to stimuli.
 Pupae do not feed and take approximately two days to develop.
 After two days, the fully developed adult mosquito forms and breaks through the
skin of pupa.
 It has a terrestrial habitat.

12. Dengue transmission
 The dengue virus is spread through a human-to-mosquito-to human cycle of
transmission.
 A person is bit by an infected Aedes aegypti, the person will develop viremia.
 Viremia is a condition in which there is a high level of dengue virus in the blood.
 On the first day of viremia, the person no shows symptoms of dengue.
 After five days the person shows the symptoms of dengue.

13.  After a mosquito feeds on the blood of some one infected with dengue virus,
the mosquito becomes a dengue vector.
 Once the virus enters the mosquito’s system in the blood meal, the virus
spread out the body of mosquito over a period of 8 to 12 days.
 After this period, the mosquito can transmit the dengue virus to the another
person while feeding.
 In rare events dengue can be transmitted during organ transplantation or
blood transfusion from infected donors.
 There is also evidence that an infected pregnant mother can transmit the
dengue virus to her fetus.

14. Laboratory diagnosis
Dengue is detected by IgM ELISA based test and NS1(ELISA)
Govt.of india approves ELISA based test only.

15. Dengue fever treatment
• Fluids are through a needle in a vein to prevent dehydration.
• The first dengue fever vaccine is produced by sanofi and goes by the
brand name Dengvaxia.
• The papaya leaves contains the enzymes like chymapapin and papain
that improves the clotting factor.
• Acetaminophen (Tylenol) and codeine may be given for severe
headache and for joint and muscle pain (myalgia).

18. Zika virus
 Zika virus is a that was fist identified in Uganda in 1947 in rhesus monkeys through
a monitoring network of sylvatic yellow fever.
 It was identified in humans in 1952
 Genre: flavi virus
 Vector: aedes mosquitos
 The symptoms are similar to dengue fever.
 There is no vaccines to treat zika virus.
 It is transfer from infected mother to fetus.

20. prevention
• Rapid cleaning device for mosquito breeding source reduction.
• Anti-larval operation using appropriate larvicides where stagnant can
not be drained.