Project N FEVER
Public Health Measures to Prevent Dengue Fever
Some Facts about Dengue
• Dengue is caused by flavivirus DENV and has 4 strains (DENV-1; DENV-2; DENV-3;
DENV-4).
• Infection with one strain of Dengue does not protect you from subsequent infection with
other strains. Protection against other DENV strain is only partial and lasts for 2-3 months
only
• While many DENV infections are either asymptomatic or produce only mild illness, DENV
can cause an acute flu-like illness called Dengue fever or break bone fever.
• Some people develop severe dengue, which may be associated with severe bleeding, organ
impairment and/or plasma leakage. This has higher risk of death if not managed properly in
time
• The risk of severe dengue is higher with subsequent infection with other strains of DENV
Virus
• 90% of those with Severe Dengue needing hospitalization are children below 5 years of age
Mosquitoes are as old as
the Dinosaurs
There are around 3000
species of Mosquito in the
world of which about 400
species are in India.
These species have
different time preference
for biting.
Dawn and Dusk are the
time when most species
are active.
Facts about Aedes Mosquitoes
• The female Aedes mosquito is responsible for transmission of these diseases because it
needs human blood, mainly for the development of its eggs and for its regular metabolism.
The male does not feed on blood.
• Female Aedes mosquito feeds every 3-4 days; and it can feed up to three times its weight.
However, if they fail to extract sufficient blood, they continue to feed every moment they can.
• Aedes aegypti has a short range and does not usually fly more than 25 meters, provided that
food is available in dwellings near its breeding sites. However, mosquitoes have been
observed to fly as far as 400 meters in search of food.
• After feeding, Aedes mosquito lays its eggs every 3-4 days in different containers, ensuring
that some of its offspring will survive predators and making the mosquito more difficult to
control. This indicates the importance of disposing of unused containers in and around the
home, and protecting useful containers that store water (sealing them or treating them with
chemical or biological products).
Some more facts about aedes
• Aedes mosquito prefers to lay its eggs in artificial recipients that contain water
(drums, barrels, and tires, mainly) in and around houses, schools, and
workplaces.
• Females can lay some 400 eggs in the course of their lives. The number of
eggs laid each time depends on the age of the female and the amount of
blood extracted.
• Aedes aegypti eggs can resist dry environmental conditions for more than a
year: in fact, this is one of the most important strategies the species employs
to survive and spread.
• Properly cleaning the surfaces of drums and barrels is more effective than
using chemical
The mosquito can
complete its life cycle,
from egg to adult, in 710 days; adult
mosquitos generally
live 4-6 weeks.
WHY DO MOSQUITOES BITE ME SO MUCH?
Carbon Dioxide
• Female mosquitoes (the kind that bite) have a thing for carbon dioxide. Using an organ known as the
maxillary palp (special nerve receptor), female mosquitoes can smell carbon dioxide emitted in human
breath up to 115 feet away.
You're pregnant
• Women in the later stages of pregnancy (third trimester) exhale 21% more CO2 than their non-pregnant
peers and attract twice as many mosquitoes. It could also be that pregnant women emit volatile odors that
draw the insects.
You're dripping with sweat
• Lactic acid, a by-product of vigorous physical activity that's excreted through sweat, is "indeed an
attractant" for mosquitoes. Exercise increases the buildup of lactic acid and heat, making a warm, sweaty
body almost irresistible to mosquitoes. Movement increases mosquito bites up to 50%.
You have type O blood
• A study in the Journal of Medical Entomology found that the bloodthirsty fiends are extra attracted to
individuals with type O blood. Individuals with Type B blood fall somewhere in the middle of the spectrum.
You just had a beer
• Booze may lead to more bites. A PLOS ONE study done in West Africa on men who drank either beer or water
revealed that "beer consumption consistently increased volunteers' attractiveness to mosquitoes."
Your genes make you more attractive
• Scientists from the London School of Hygiene & Tropical Medicine reported that certain people produce
natural mosquito repellents, a trait that appears to be genetically controlled.
Skin Bacteria
• Research suggests that certain types and quantities of bacteria on human skin can attract mosquitoes. This
may explain why mosquitoes are drawn to our ankles and feet, which are areas that often harbor highly active
bacteria colonies, and can be smelly.
Clothing
• Mosquitoes are highly visual creatures. according to studies, dark, bright colors have been shown to attract
more mosquitoes than lighter colors.
Protection
• Wearing light coloured long sleeves and pants is the most obvious way to help prevent mosquito bites.
• Use mosquito nets for children and adult sleeping during the day
• For added protection, use a repellent containing 10 -30% DEET, or Picaridin. or another active ingredient
approved by WHO and the Centers for Disease Control and Prevention (CDC).
Aedes characteristics: Rationale for vector control strategies
Key characteristic
Control strategy
Day feeder, bites during day
Protection during day
– Door and window screens, impregnated with insecticide better
– Wear full sleeves bright clothes during day, when going out
– Mosquito repellents during day, apply on cloth or skin directly
– If sleeping during day, use bed nets, impregnated better
Breeds in stagnant artificial water
collections
Killing the Larvae
– Prevent water clogging in and around your house/ work upto 500m
– Clean at least once every week such as Every Sunday
– Use chemical or biological (eg. fish) methods to kill larvae in water
collection that cannot be drained
- 7 days from Larvae to adult stage
Flies up to 500mts around breeding site
Aedes mosquito rests on walls /
surfaces before and after feeding
Aedes mosquito sensitive to insecticides
Female adult transfers virus
Killing the Adult Aedes mosquito
– Outdoor and Indoor insecticide sprays ;
– Attractive toxic Sugar baits
– Mosquito traps
– Genetically modified Aedes; compete but do not reproduce
Setup Sugar baits
We hope to develop a team of
Dengue Community Warriors
Or Window and
door screens
Thank You