DOST School-based O/L Trap Program

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DOST School-based O/L Trap
Program
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Objective

• General
• Provide the scientific framework of the OL Trap
  Program of Dengue vector control

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Objective

• Specific
• Explain the concept of vector control
• Explain dengue vector control
• Explain Integrated Vector Control (IVC) and
  Integrated Vector Management (IVM)
• Discuss the components of IVC from vector biology
  to control measures

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Objective

• Specific
• Describe vector surveillance as it applies to
  dengue OL Trap in a classroom setting
• Answer the fourteen questions enumerated in the
  situationer

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Objective

• Specific
• Identify the following
• Mosquito eggs in a lawanit paddle
• Ovitrap (black tumbler and paddle)
• Mosquito larva
• Pupae
• Positive/negative trap
• Adults
• Entomological forms (Ovitrap/OL Trap)
• Pellets

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Situationer

• Urban / semi-urban setting
• Big public elementary school in City X
• 3-story building (30-35 feet)
• 10 classrooms per floor 16x20 feet per room)
• 50-55 pupils occupy one classroom from 8am-5pm

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Situationer

• 1,200-1,500 pupils
• No electric fans in the classrooms
• One aircon and/or electric fan at principals
  office
• Houses near the school
• Presence of flower vases, water containers

Click Here
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Questions

• How many ovitraps/OL Traps are needed to be
  installed in the elementary school?
• Where should the traps be installed?
• When should the traps be installed?
• How frequent should the traps be installed?

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Questions

• What is the procedure to be followed in
  installing the traps? In servicing the traps?
  What is the meaning of servicing the traps?
• Who will install and service the traps?

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Questions

• Who will monitor and check the traps?
• Monitor
• Empty tumbler
• Missing tumbler/paddle
• Check
• If positive/negative?
• Is there a form to be filled-out?

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Questions

• What index needs to be obtained?
• What formula is to be used?
• What is the meaning of the index obtained?
• Who will record and compute for the index?

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Questions

• To whom should the data be submitted to? Why?
• For how long will this ovitrapping be done?

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Whats inside?

• Vector
• Surveillance
• Prevention and Control

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Vector

• An arthropod (insects, mites, ticks) that are
  capable of acquiring, supporting the development
  and transmitting a pathogenic agent (bacteria,
  viruses, parasites) from one host to another host
• Example mosquito Aedes sp.
  transmitting dengue virus

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Vector Control

• suppression of a target population by using
  measures to alter the vector reproductive
  capacity or potential (Vector Genetics Course,
  2010, India)

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Dengue Vector Control

• Application of various anti-DEN mosquito measures
  to alter the life cycle of the mosquito

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Dengue Vector Control

• Specific Targets
• Prevent and cut dengue transmission by
• Targeting larval stage through
• Trapping
• Larviciding
• Container management
• Environmental sanitation

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Dengue Vector Control

• Specific Targets
• Prevent and cut dengue transmission by
• Targeting adult stage through
• Adulticiding
• Space-spraying
• Aerosol treatment
• Genetic manipulation of
  reproductive capacity of mosquito

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Dengue Vector Control

• Specific Targets
• Prevent and cut dengue transmission by
• Prevention of man-mosquito contact
• curtains
• Screening of doors and windows
• Long pants
• Repellants

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Integrated Vector Control

• Combination of 2 or more vector control
  activities supplementary to each other towards
  reduction of dengue incidence

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Integrated Vector Management

• utilization of technical and managerial measures
  to bring about an effective degree of vector
  suppression to prevent and
  control
  transmission

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Components of IVC

• Vector biology/behavior
• Surveillance tool (Ovitrap/OL Trap surveillance
  index)
• Critical Threshold Density Index (effective
  degree of vector suppression Ovitrap index
• Control Measures
• Monitoring and evaluation

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The Vector
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Vector Biology
Aedes aegypti Aedes albopictus
General characteristics - primary vector - involve in cases of epidemics - urbanized areas - lives indoors - secondary vector - maintains the virus in the environment - rural areas - lives outdoors
Breeding habitat - confined to artificial containers indoors - prefers to breed outdoor, in natural containers
Resting habits - rests in cool, dark corners of the house - rests outdoors in clearings and vegetations
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Morphology
Aedes aegypti Aedes albopictus
Size - 3-4 mm - same
Color - dark brown to black - same
Thorax - lyre-shaped white marks or scales - single white marks
Abdomen - with white scales - with white and dark marks
Legs - with white marks - same
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Vector Characteristics

• Biting Habits
• daybiters with two peaks of biting time
• 1 to 2 hours after sunrise
• 1 to 2 hours before sunset
• only female mosquitoes bite because of the
  requirement of blood for oviposition
• males do not bite but feed on plant juices and
  nectar of flowers
• man is the preferred host but
  in his absence, lower
  vertebrates serve as substitute

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Vector Characteristics

• Flying Habit
• do not fly great distances
• farthest flight distance is within 200 to 400
  meters radius from their breeding places
• Adults found around 50 meters from the breeding
  sources

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Bionomics

• at temperatures lt10oC and gt40oC, no developmental
  process takes place
• females mates with male only once
• Blood meal takes place after 48
  hours from emergence and
  after mating for egg
  production

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Bionomics

• oviposition takes place about 2 to 5 days from
  blood engorgement
• prefers dark-colored background for oviposition
• lays egg 3 to 4 times in its lifetime
• 60 to 100 eggs per batch
• Survival potential 20-30 days

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Life Cycle (10-12 days)
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Surveillance
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Vector Surveillance

• Collection and interpretation of data which can
  be used to guide mosquito vector control
  operations
• Establish baseline
• Presence or absence of vector
• Species?
• Density?
• Changes?

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Dengue Surveillance Tool

• Classical OVITRAP/LARVITRAP (black tumbler,
  paddle, water)
• Modified OVITRAP is the OLTRAP (black container,
  paddle, water and organic
  larvicide)
• 2 adults (females)
  emerging per day
  (Malaysian experience)

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Difference between tools
Ovitrap OL Trap
Eggs on the paddle - Yes - Yes
Live larva seen - Yes - No
Action - Eggs trapped - Eggs trapped
With organic larvicide Value-added None None - Yes - Additional attractant (kills larva)
Risk - with white marks - same
Benefit - Breeds Aedes, if uncollected (set and collect) - Breeds Aedes, if uncollected after 7 days (set and collect)
Index (CTDI) - Ovitrap index 10 - OLTrap 10
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Ovitrap Index

• Total Number of positive traps
• Total Number of traps planted
• If OI is gt10, the place is vulnerable to dengue
  transmission.

X 100
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Critical Threshold Density Index (CTDI)

• Actual target for the degree of vector
  suppression
• Predictive value for the prevention of dengue
  transmission

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Remember

• A positive trap means there is at least one
  mosquito laying its eggs in the sampling site
  (surveillance site)
• Aim is eliminate this one mosquito laying its
  eggs

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What is DOST Mosquito Ovi/Larvicidal (OL) Trap
System?

• Is a system used to control the population of
  the
• dengue carrying Aedes mosquitoes.
• It has three important parts a black
  container, a
• small strip of lawanit measuring 1 x 6.5 for
  
• mosquitoes to lay their eggs on, and pellets
  as
• larvicide.
• The OL-Traps ovicidal and larvicidal effect
• prevent the next generation of mosquitoes from
• reaching adulthood, thus curbing the Aedes
• mosquito population.

Tumbler
Pellets
Paddle
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HOW THE OL-TRAP WORKS?

• The idea is to attract mosquitoes particularly
  the Aedes aegypti and albopictus (dengue carrier)
  to lay their eggs on the lawanit paddle.
• The trap creates optimum conditions for this
  species to lay its eggs stagnant, clean, clear
  water, dark area and damp rough surface.

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• The eggs will either be trapped in the lawanit
  paddle or find its way into organic solution,
  where they are killed before transforming into
  adults.

Eggs
Larvae
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Distribution of OL Trap
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Distribution of OL Trap
CLASSROOM 1 OL Trap indoor and 1 OL Trap-outdoor
CLASSROOM 1 OL Trap indoor and 1 OL Trap-outdoor
CLASSROOM 1 OL Trap indoor and 1 OL Trap-outdoor
CLASSROOM 1 OL Trap indoor and 1 OL Trap-outdoor
SCHOOL
CLASSROOM 1 OL Trap indoor and 1 OL Trap-outdoor
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Distribution of OL Trap
1 OL Trap indoor 1 Tumbler (Black Container) 1
sachet of pellet per week 1 pc paddle per month
1 OL Trap outdoor 1 Tumbler (Black Container) 1
sachet of pellet per week 1 pc paddle per month
CLASSROOM
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Servicing the OL Trap

• OVITRAPS are installed and serviced every seven
  days in locations where transmission of dengue is
  probable
• nursery schools
• pre-schools
• elementary schools
• Hospitals
• community with confirmed dengue cases
• Ovitrap Index gt 10

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Before OL Trap Installation

• Clean-up all possible breeding sites/containers
  found inside/outside the classrooms DO SEARCH
  and DESTROY

Artificial containers (man-made)
Natural containers
1. Tree Holes, bamboo stumps 2. Leaf axils,
fallen leaves 3. Ground Depressions
1. Flower vases and pot plates 2. Pails,
water-storage jars, basins 3. Discarded
receptacles 4. Choked roof gutters 5. Gully
Traps 6. Unused toilet bowls and cisterns 7.
Aircon Tray and dish rack tray 8. Concrete drains
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Where to set up the DOST OL-Trap?

• A. Indoor
• Under the sink
• Corner of the room
• Under the cabinet
• Under the bed
• Inside the comfort room

• B. Outdoor (covered area)
• Corner of the classroom
• Near vegetation
• Piles of woods/hollow blocks
• Garden

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Setting the OL Trap

• Step 1
• Fill the plastic tumbler with tap
  water up to the lined mark just
  above the DOST logo (250 ml)

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Setting the OL Trap

• Step 2
• Pour one pack OL pellets
  into the plastic cup
• Stir thoroughly to ensure
• pellets are dissolved

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Setting the OL Trap

• Step 3
• Place the lawanit stick in the
  solution with the rough
  surface facing up

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Setting the OL Trap

• Step 4
• Place 1 cup each inside
  and outside the classroom
  in a low-lying and dark
  area
• If outside, protect from direct
  sunlight and rainfall
• Take care not to spill the
  contents
• Keep out of reach of children
  and animals

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Setting the OL Trap

• Step 5
• Collect trap and note for
• the following on the seventh (one week after
  installation (every Monday) day
• Eggs on the paddle
• Live larva/pupa
• The presence of even one
• larvae indicates a positive trap
• Record in the OL Trap
  Monitoring Sheet (3 copies)

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Setting the OL Trap

• Step 6
• Repeat steps 1-5 every 7 days
• Set and collect the traps every Monday
• Finalize report every Tuesday
• Note If collection period falls on a holiday,
  please collect traps a day before

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Cleaning the Trap

• Vigorously brush-off into
  the solution eggs stuck
  into the lawanit creases
• Kill the larva/eggs by
  pouring hot water into
  the black tumbler
• Dispose contents
  properly by pouring
• contents on dry ground

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Identifying a POSITIVE/NEGATIVE Trap
Presence ()/ absence (-) of eggs in the paddle
Presence ()/ absence (-) of larvae in the
container/tumbler with water
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An OL Trap is positive or negative if
Paddle Tumbler RESULT
Positive () Positive () POSITIVE ()
Positive () Negative (-) POSITIVE ()
Negative (-) Positive () POSITIVE ()
Negative (-) Negative (-) NEGATIVE (-)
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OL Trap Monitoring Sheet
Click here
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Filling Out of Monitoring Sheet
Click Here
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Prevention / Control
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School Assemblies
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School Dengue Brigade
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Search and Destroy Activities
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Brigada Iskwela
(School Clean-ups)
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Installation of Long-lasting Insecticide-treated
Nets (LLINs)
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Space-spraying Activities
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Dengue prevention and control rests primarily on
the people who live in the houses where the
problems occur and by the people who help create
the mosquito larval habitats by their lifestyles.