DOST-DOH Dep ED O/L Trap ProgramDesiree R. Jaleco, RN

School Nurse IISagay National High School

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Objective

• General Provide the scientific framework of the OL

Trap Program of Dengue vector control

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Dengue Fever

• Definition Also known as breakbone Fever An infectious tropical disease caused by the

Dengue Virus Mosquito-borne viral disease Caused by one of four serotypes of

flaviviruses

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Four Strains of Serotypes Viruses

• DENV – I• DENV – II• DENV – III• DENV - IV

All four types can cause full spectrum of disease.

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Classification (WHO)

• DENGUE FEVER• DENGUE HEMORRHAGIC FEVER

GRADE 1 – presence of bruises GRADE 2 – presence of spontaneous bleeding GRADE 3 & 4 – referred as dengue shock

syndrome

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Signs and Symptoms

• Dengue Fever Fever Headache Muscle and joint pains Skin rashes

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DENGUE HEMORRHAGIC FEVER

• severe form• fatal• patients develop hemoconcentration

Dengue Shock Syndrome(DSS)

shock and death

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DENGUE SHOCK SYNDROME

EARLY SIGNS

RestlessnessCold clammy skinRapid weak pulse

Narrow pulse pressureHypotension

ADVANCE SIGNS

Severe abdominal painProtracted vomiting

Change in temperatureChange in mental status

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Management

• No specific treatment• Only symptomatic and supportive treatment

Paracetamol (Acetaminophen) Oral Rehydration IV fluids Blood Transfusion (packed RBC or Whole Blood) Discontinue IV fluids during recovery phase to

prevent fluid overload

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The VectorThe Vector

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Vector Biology

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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

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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 <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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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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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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DOST-DOH Dep ED OL TrapOvicidal/Larvicidal Trap

• a method used to control the reproductive capacity of dengue carrying mosquitoes

• A project of DOST-DOH using a natural/organic larvicide solution

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Usage of OL Trap

• Larvicide solution emits odor that attracts female Aedes mosquitoes for oviposition

• The lawanit paddle submerge in solution through capillary action serves as the breeding place

• The larvicide solution kills the eggs and larva

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Servicing the OL Trap

• OVITRAPS are installed and serviced every six 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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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

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Setting the OL Trap

• Step 5 Collect trap and note for the following on the sixth 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 6 days

Set the traps every Wednesday Collect traps every Tuesday Finalize report every Tuesday Submit a copy of the report to city dengue

coordinators every WednesdayNote: 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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Ovitrap Index

Total Number of positive trapsTotal Number of traps planted

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

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X 100%

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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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THANK YOU!

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