A mosquito-borne viral disease occurring in tropical and subtropical areas.

1. DENGUE
FEVER

2.  Dengue fever is an acute infectious viral
disease, also known as break bone fever.
It is a arthropod-borne(abro viral) illness
in human. It is caused by infection with
one of the 4 serotypes of dengue
virus[DENV1,2,3,4], which is a flavivirus(a
genus of single-stranded) non segmented
RNA viruses).
Dengue is transmitted by mosquitoes of
the genus Aedes.
Dr Benjamin Rush a professor of chemistry
and medical theory at the UPEN, during
the Philadelphia epidemic 1779-1780,first
described the dramatic symptoms of
dengue as break bone fever.

4. A.aegypti and Dengue distribution in 2006
A.aegypti distribution with history of
epidemic dengue
A. aegypti distribution without history of
epidemic dengue

5. • When a mosquito carrying dengue virus bites a person, the
virus enters the skin together with the mosquito's saliva. It binds
to and enters white blood cells, and reproduces inside the cells
while they move throughout the body.
• The white blood cells respond by producing a number of
signalling proteins, such as cytokines and interferons, which are
responsible for many of the symptoms, such as the fever, the
flu-like symptoms, and the severe pains. In severe infection, the
virus production inside the body is greatly increased, and many
more organs (such as the liver and the bone marrow) can be
affected.
• Fluid from the bloodstream leaks through the wall of small
blood vessels into body cavities due to capillary permeability.
As a result, less blood circulates in the blood vessels, and the
blood pressure becomes so low that it cannot supply sufficient
blood to vital organs.
• Furthermore, dysfunction of the bone marrow due to infection
of the stromal cells leads to reduced numbers of platelets, which
are necessary for effective blood clotting; this increases the risk
of bleeding, the other major complication of dengue fever.

7. WHAT HAPPENS IF DENGUE AFFECTS
YOU TWICE?
• A first-time dengue patient is relatively safe.
But if he suffers a second attack of a different
type, then haemorrhagic dengue is certain.
• This happens due to the conflict between the
immunity developed after each attack.
• Dengue leads to high fever with joint pain and
headache.
• Haemorrhagic dengue might lead to bleeding
from the eyes, nose and through urine or stool.

8. • When Dengue virus is first encountered, this is
exactly what happens and the body generally
defends itself well.
• A few copies of the successful antibody are
then stored, in case the body runs into that
same virus again. When the second and
different strain of dengue is encountered, the
antibodies and white blood cells go to attack.
• However, this new virus is just a little bit
different and the antibody has trouble
attaching properly. Unfortunately, the antibody
can attach just well enough to allow the virus
access to its white blood cell passenger,
introducing the virus to a whole new type of
cell and a great opportunity to rapidly
reproduce

10. • If a person has suffered from dengue in the
past year, they must take additional
precautions to prevent the disease because a
second attack of dengue may be more
dangerous than the first attack.
• There are four different types of dengue, and
one can, therefore, suffer from dengue four
times in his or her lifetime. The second or
subsequent dengue infections tend to be more
serious.
• A person with dengue can also simultaneously
suffer from malaria. Malaria and dengue
together can lower platelet counts to a
dangerous level leading to complications.

12. Here are a few tips for
preventing the dengue fever for
the second time:
• Reduce your exposure to the dengue mosquito. Sleep
in a room that has a mosquito repellent and a
mosquito net may also be a good option.
• Keep indoors during early morning and late afternoon,
especially dusk.
• Do not allow stagnant water to be nearby. These are
the breeding grounds of mosquitoes.
• Drain air coolers, plant bearing pots regularly.
• Drink plenty of water from a known and safe source.
• Limit travel to areas that are suffering with this
epidemic.

13. These tips may help reduce
your risk of mosquito bites:
• Stay in air-conditioned or well-screened housing. The mosquitoes that
carry the dengue viruses are most active from dawn to dusk, but they
can also bite at night.
• Wear protective clothing. When you go into mosquito-infested areas,
wear a long-sleeved shirt, long pants, socks and shoes.
• Use mosquito repellent. Permethrin can be applied to your clothing,
shoes, camping gear and bed netting. You can also buy clothing made
with permethrin already in it. For your skin, use a repellent containing
at least a 10 percent concentration of DEET.
• Reduce mosquito habitat. The mosquitoes that carry the dengue virus
typically live in and around houses, breeding in standing water that can
collect in such things as used automobile tires. Reduce the breeding
habitat to lower mosquito populations.