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BARRIERS THAT LIMIT IMPLEMENTATION OF

THERMAL FOGGING INTERVENTION FOR

VECTOR CONTROL IN MEDELLIN, COLOMBIA

ANDRÉS F. USUGA, LINA M. ZULUAGA-IDÁRRAGA, RAÚL

ROJO, ENRIQUE HENAO, GUILLERMO L. RÚA-URIBE

30 JUNE 2019

DHAKA, BANGLADESH

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Thermal fogging

• Dispersion of a liquid insecticide into the air

• Use for abatement of adult mosquitoes

• Only effective while the droplets remain airborne

• Guidelines for use are set by PAHO/WHO

INTRODUCTION

Integrated Management Strategy for Dengue (IMS-Dengue)

Thermal fogging in Medellin

• Scheduling

• Preparation

• Awareness

• Applied inside houses due to access problems

for vehicles needed for outdoor fogging

Source: http://iris.paho.org/xmlui/bitstream/handle/123456789/34860/PAHOCHA17039_eng.pdf?sequence=5&isAllowed=y

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Expected control of dengue not achieved

JUSTIFICATION FOR RESEARCH

Problems with implementation

Difficulty interveningwhen and where it is

needed

Weak adherence to application guidelines

Low coverage -residents reject fogging

in their homes

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OBJECTIVE

Propose solutions to improve effectivity ofintervention

Acceptability ofthe intervention

by residents

Temporal and spatial

opportunity of the intervention

Identify barriers

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METHODOLOGY

Cross-sectional observational study

Mixed methods design

• Explanatory sequential type

Neighborhoods prioritized for intervention

• Timeliness of the treatment

• Rejection by residents

• Factors associated with rejection described and quantified

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9/21 city sectors

18/250 neighborhoods

Study site: Medellin, Colombia

METHODOLOGY

Neighborhoods

visited

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Data collection

METHODOLOGY

Analyzing how quickly intervention occurspost-notification and if it targets thelocation of infection

Public Health Surveillance System(SIVIGILA)

Report of intervened areas

Analyzing reasons residents reject

interventions

Focus group

Categories: Experiences, Meanings,

Reasons

Awareness

Rejection

Active rejection

Passiverejection

Acceptance

Format 1

Format 2

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Time to intervention; n:64

RESULTS

Variable Median (IQR)

Days between onset of symptoms and treatment 32 (25.0-40.0)

Days between notification of surveillance system and treatment 25 (20.0-36.5)

Did intervention occur in the location of infection; n:23

Probable place of infection n (%) Places of

intervention

Opportunity

Intervención

Home 5 (21.7) Home Yes

Home and Educational

institution or Job15 (65.2) Home Partially

Job/Outside Medellin 3 (13.0) Home No

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RESULTS

89.0%

4.9%4.5%

0.6% 0.6%0.5%

Causes of passive rejection

Closed House

Minor alone at home

Bedridden sick person

Person with disabilitiesalone at homeOfficial recommends notinterveningSick person who cannotget out at home

Acceptancen=2393 (53. 7%)

Passive rejectionn=1633 (36.7%)

Active rejectionn=429 (9.6%)

Acceptance and rejection of

intervention

10.3%

12.8%

8.4%

33.1%

24.5%

3.0% 7.9%

Causes of active rejection

Nursing or pregnant woman

Sick person not bedridden

Pets

Busy

Not interest

No reason given

Othersn=4455

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No previousinterventions

Perception thatfogging affectspeople’s health

Don’t see ordon’t feelmosquitoesinside home

Perception that fogging doesn’t

control pests other than mosquitoes

Rejection of interventionassociated with

RESULTS

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CONCLUSIONS/RECOMMENDATIONS

High rejection rate was the main barrier to full coverage

Time between notification of dengue cases and intervention is longer than expected

Residents understand thermal-fogging helps to reduce densities of mosquitoes. However, it is also perceived as harmful to human health

We recommend 1) to strengthen community education about thermal fogging, 2) to carry out interventions on schedules that will maximize access to houses and 3) to identify bottlenecks in the notification system to reduce time of intervention

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THANK YOU