MOSQUITO OL-TRAP 18 May 20152DOST School-based O/L Trap Program Objective General Provide the scientific framework of the OL Trap Program of Dengue

MOSQUITO OL-TRAP

April 18, 2023 2DOST School-based O/L Trap Program

ObjectiveObjective

• General Provide the scientific framework of the OL

Trap Program of Dengue vector control

MOSQUITO OL-TRAP


ObjectiveObjective

• 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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ObjectiveObjective

• 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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ObjectiveObjective

• 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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SituationerSituationer

• 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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SituationerSituationer

• ~ 1,200-1,500 pupils• No electric fans in the classrooms• One aircon and/or electric fan at

principal’s office• Houses near the school• Presence of flower vases, water

containers

Click Here

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QuestionsQuestions

• 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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QuestionsQuestions

• 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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QuestionsQuestions

• 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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QuestionsQuestions

• 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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QuestionsQuestions

• To whom should the data be submitted to? Why?

• For how long will this ovitrapping be done?

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What’s inside?What’s inside?

• Vector• Surveillance• Prevention and Control

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VectorVector

• 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 ControlVector 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 ControlDengue Vector Control

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

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• Specific Targets Prevent and cut dengue transmission by:

Targeting larval stage through Trapping Larviciding Container management Environmental sanitation

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Targeting adult stage through Adulticiding

» Space-spraying» Aerosol treatment

Genetic manipulation of reproductive capacity of mosquito

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Prevention of man-mosquito contact curtains Screening of doors and windows Long pants Repellants

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Integrated Vector ControlIntegrated 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 ManagementIntegrated 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 IVCComponents 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 VectorThe Vector

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Vector BiologyVector 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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MorphologyMorphology


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 CharacteristicsVector 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 CharacteristicsVector 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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BionomicsBionomics

• at temperatures <10oC and >40oC, 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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BionomicsBionomics

• 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 Life Cycle (10-12 days)(10-12 days)


Eggs:- Black and oval in

shape- Laid singly above

water surfaces of containers

- Without float- Viability: 6 months

to 1 year due to the presence of chorion

2 - 3 days Larva:- Feeding stage- Breeds in clean and

non-polluted water- Short and stout

siphon with one pair of hair tuft

- Rests at an angle to the water surface

6 - 8 days Pupa-Non-feeding stage-Breeding trumpet is long, slender with narrow opening

1 - 2 days

Adult-Maxillary pulps shorter than probosis-Wings uniformly grayish black-Body and legs are black with distinctive white patches throughout-Thorax has markings

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SurveillanceSurveillance

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Vector SurveillanceVector 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 ToolDengue 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 toolsDifference between tools


Ovitrap OL Trap

Eggs on the paddle - Yes - Yes

Live larva seen - Yes - No

Action - Eggs trapped - Eggs trapped

With organic larvicideValue-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 IndexOvitrap Index

Total Number of positive trapsTotal Number of traps planted

If OI is >10%, the place is vulnerable to dengue transmission.


X 100%

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Critical Threshold Density Index Critical Threshold Density Index (CTDI)(CTDI)

• Actual target for the degree of vector suppression

• Predictive value for the prevention of dengue transmission


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Remember: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 What is DOST Mosquito Ovi/Larvicidal (OL) Trap (OL) Trap System? 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-Trap’s ovicidal and larvicidal effect prevent the next generation of mosquitoes from reaching adulthood, thus curbing the Aedes mosquito population.

Tumbler

PelletsPaddle

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HOW THE OL-TRAP WORKS?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 TrapDistribution of OL Trap


CLASSROOM1 OL Trap –indoor

and 1 OL Trap-outdoor









SCHOOL

1 OL Trap indoor

1 Tumbler (Black Container)

1 sachet of pellet per week1 pc paddle per month

1 OL Trap outdoor

1 Tumbler (Black Container)

1 sachet of pellet per week

1 pc paddle per monthCLASSROOM

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Servicing the OL TrapServicing 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 = > 10%


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Before OL Trap InstallationBefore 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. Flower vases and pot plates2. Pails, water-storage jars, basins3. Discarded receptacles4. Choked roof gutters5. Gully Traps6. Unused toilet bowls and cisterns7. Aircon Tray and dish rack tray8. Concrete drains

1. Tree Holes, bamboo stumps2. Leaf axils, fallen leaves3. Ground Depressions

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Where to set up the DOST OL-Trap? Where to set up the DOST OL-Trap?

AA. Indoor:. Indoor: Under the sink Corner of the room Under the cabinet Under the bed Inside the comfort room

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

blocks Garden

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Setting the OL TrapSetting 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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• Step 2 Pour one pack OL pellets

into the plastic cup Stir thoroughly to ensure pellets are dissolved


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• Step 3 Place the lawanit stick in the

solution with the rough surface facing up


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• 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 TrapSetting 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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• Step 6 Repeat steps 1-5 every 7 days

Set and collect the traps every Monday Finalize report every TuesdayNote: If collection period falls on a holiday, please

collect traps a day before


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Cleaning the TrapCleaning 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 TrapIdentifying 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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Paddle Tumbler RESULT

Positive (+) Positive (+) = POSITIVE (+)

Positive (+) Negative (-) = POSITIVE (+)

Negative (-) Positive (+) = POSITIVE (+)

Negative (-) Negative (-) = NEGATIVE (-)

An OL Trap is positive or negative if;

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OL Trap Monitoring SheetOL Trap Monitoring Sheet


Click here

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Filling Out of Monitoring SheetFilling Out of Monitoring Sheet


Click Here

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Prevention / ControlPrevention / Control

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School AssembliesSchool Assemblies


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School Dengue BrigadeSchool Dengue Brigade


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Search and Destroy ActivitiesSearch and Destroy Activities


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Brigada Iskwela Brigada Iskwela (School Clean-ups) (School Clean-ups)


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Installation of Long-lasting Installation of Long-lasting Insecticide-treated Nets (LLINs)Insecticide-treated Nets (LLINs)


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Space-spraying ActivitiesSpace-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.”

Documents

MOSQUITO OL-TRAP 18 May 20152DOST School-based O/L Trap Program Objective General Provide the scientific framework of the OL Trap Program of Dengue