dengue fever prevention presentation
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Dengue Fever Prevention and
Control
Saleem M. Rana, PhD
The Dengue Fever a Global Problem
• During epidemics of dengue, infection rates among those who have not been previously exposed to the virus are often 40% to 50%, but can reach 80% to 90%.
• An estimated 500 000 people with DHF require hospitalization each year, a very large proportion of whom are children. About 2.5% of those affected die.
• Without proper treatment, DHF fatality rates can exceed 20%.
• Wider access to medical care from health providers with knowledge about DHF - physicians and nurses who recognize its symptoms and know how to treat its effects can reduce death rates to less than 1%.
Aedes aegypti Aedes albopictus
Aedes aegypti
Aedes albopictus
Behavior
Day-time biter
Lives outside
But comes indoors
May lay eggs indoors
Lays eggs in artificial containers
Anything that can hold water
Rests in low, shaded areas.
Under tables, chairs
In machinery- if damp
More behavior
Day-time biter – also in lighted rooms at night.
Silent flier – no buzz in your ear.
Very gentle on skin and not easily felt biting.
Adults not active under 15-16 degrees.
Adults not killed by cold, just go inactive.
Eggs laid containers of water
Egg to Larva to Adult in one week or less.
Movies
Comparison of Aedes (Larvae)
Characters Ae. aegypti Ae.albopictus
ANTENNAE single hair near middle single hair near saddle
HEAD upper & lower hairs
single
upper & lower hairs
single
THORAX heavy hooks on sides weak or no hooks on side
COMB SCALES pitchfork-shaped; 7-12 in
1 row
thorn-like; in 1 row
SIPHON index 2.0; pectin evenly
spaced
pectin evenly spaced
GILLS all the same length,
rounded; longer than anal
segment
all the same length,
rounded; longer than anal
segment
Comparison of Aedes (Adult)
Characters Ae. aegypti Ae.albopictus
PALPS dark with white tip;
clypeus white
dark with white tip;
clypeus black
PROBOSCIS dark dark
SCUTUM dark with white lyre-
shaped pattern
dark with white median
stripe
THORAX dark with patches of
white scales
dark with patches of
white scales
WINGS dark dark
ABDOMEN dark with narrow white
basal bands
dark with narrow white
basal bands
HIND LEGS dark with white basal
bands
dark with white basal
bands
Possible Weapons to Fight Dengue
Fever
• Drugs that kill the virus in humans
• Insecticides that kill the mosquito vector
• Vaccines
1. Drugs
• No specific anti viral
• Symptomatic treatment
2. Insecticides:
Mosquitoes Quickly Acquire Resistance
Before During After
Biologic niche intact Mosquitoes return
3. Vaccine
Does not exist (yet)
Mosquito Breeding
No comments
Before sunrise
Near sunset
Symptoms
Dengue fever is a flu-like illness with varying characteristics: Infants and youths often experience an undifferentiated febrile disease
with rash.
Older children and adults may have a mild febrile syndrome but more typically experience: high fever,
severe headache,
pain behind the eyes,
muscle and joint pains and
rash.
Typically, a person will develop dengue fever as a result of initial exposure to one serotype. Upon recovery, a patient develops immunity to this single serotype.
SYMPTOMS
Upon second infection with a different serotype:
the patient stands a greater risk of developing dengue haemorrhagic
fever (DHF), a more serious and potentially fatal disease.
DHF is characterized by:
o High fever, haemorrhagic phenomena, enlarged liver and
circulatory failure.
o A sudden onset of fever is the first indication of DHF,
accompanied by facial flush and other symptoms of
dengue fever.
o The fever persists for 2-7 days and can reach 41° C,
followed by febrile convulsions and haemorrhagic phenomena.
SYMPTOMS
The patient may recover and symptoms abate. But if left untreated, the patient may go into shock (DSS) with a rapid, weak pulse, followed by signs of circulatory failure such as cool, blotchy skin. Without proper treatment, the patient may die within 12-24 hours.
Strategies for Dengue Control
National Strategy.
SOLID WASTE
MANAGEMENT
CASE
MANAGEMENT
CAPACITY
BUILDING
ACSM
SURVEILLANCE
VECTOR
CONTROL
DENGUE
CELL
Control Strategy
Selective integrated vector control, with community and
intersectoral participation
Active disease surveillance based on a strong health information system-involves clinical and laboratory-based
vector surveillance for monitoring and evaluation of control
programmes.
Control Strategy
Emergency preparedness for development of emergency and contingency plans, including education of the medical community, hospitalization plans, case management and emergency vector control.
Capacity building and training for surveillance, laboratory diagnosis, case management and vector control at professional, supervisory, technical and field levels.
Vector control research including studies on vector biology and control, disease relationships, design and management of control programmes (including social and economic approaches) and cost benefit analyses. The relative impact of the components of integrated vector control require further elucidation.
Problems And Challenges
• demographic changes ▫ uncontrolled population growth
▫ Mobility
▫ unplanned urbanization.
▫ man-made larval habitats e.g. household water storage
containers, discarded solid waste items, such as plastics, glass containers and used automobile tyres.
NEW APPROACH:
GENETIC MODIFICATION OF MOSQUITOES
1) GENETICALLY ENGINEER MOSQUITOES
TO MAKE THEM RESISTANT TO VIRUS
2 ) INTRODUCE THE REFRACTORY GENE(S)
INTO MOSQUITO POPULATIONS
LESS TRANSMISSION LESS DENGUE FEVER
Monthly Temperature, Rainfall and DF 2008 in Lahore
100 88
27 31 40
33 27 24
33
19 7
12
80 71 67
60
80 86
93 96
40
57 60
36
20 24 27 20
1st week 2nd week 3rd week 4th week
DF +ve cases Aedes egypti Aedes albopictus
larvae Fogging larvicide
IRS
Correlation between dengue fever prevalence, vector density and control activities 2008 in Lahore
Annual correlation between dengue fever, temperature and rainfall 2008 in Lahore
Message Start
Active disease surveillance based on :
a strong health information system to involves the
clinical and laboratory-based dengue surveillance
for early detection of epidemics, and
Develop a quick reporting system from:
FLCF ----EDOH---DGHS
vector surveillance for monitoring and evaluation of
control programmes.
Aware the Community
Thanks
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