Control of Vectors – Dengue Fever

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Control of Vectors Dengue Fever

• Department of Community Medicine

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Definition

• Vector Control is one of the aspects in the
  concept of control of vector borne diseases. It
  can be defined as any planned, organized effort
  with most suitable/appropriate interventions
  operated to reduce the population status of
  dengue vectors, in order to break the
  transmission cycle.

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Vector Dynamics

• A thorough knowledge of bionomics and ecology of
  the vector species is a pre-requisite for
  considering suitable interventional methods.
• Highly Anthropophilic .
• Peridomestic Domestic
• Eggs withstand long periods of desiccation more
  than a year -A factor complicating eradication of
  dengue vectors (Aedes aegypti and Ae.albopictus)
• Proliferation
• Diurnal Activity
• Longevity Density
• Susceptibility status

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DIFFERENT VECTORCONTROL MEASURES

• ENVIRONMENTAL MANAGEMENT (EM)
• CHEMICAL CONTROL
• BIOLOGICAL CONTROL
• INTEGRATED APPROACH

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EM includes

• Planning
• Organization
• Carrying out and monitoring activities for the
  modification or manipulation of environmental
  factors
• To reduce vector propagation and.
  human-vector-pathogen contact.

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Types of environmental management

• Environmental modification-
• Long-lasting Physical transformation of vector
  habitats
• Environmental manipulation
• Temporary changes to vector habitat as a result
  of planned activity to produce conditions
  unfavorable to vector breeding.
• Changes to human habitation and behaviour-
• Efforts to reduce human vector pathogen contact
  (escaping infective bites).

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• Space Spraying - spreading of microscopic
  droplets of , insecticide in to the sir
• Thermal Fog
• ULV aerosols and Mists
• Modes of Application of Aerosols and Mists
• Portable machines used in small areas
• Vehicle mounted generators
• Aerial spraying with Air Crafts
• Parameters
• Time
• Temperature
• Wind Velocity

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PERSONAL PROTECTION

• Use of Mosquito, Nets, Repellents, Screening of
  Houses / Hospital wards.
• Special Groups
• Bed-ridden people
• Infants
• Day-time sleeping people -Tourists
• Short-term visitors -Residents
• Those staying longer in endemic areas.

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BIOLOGICAL CONTROL

• Larvivorous fish
• Gambusia affinis Poecilia reticulate, Aplochelius
  panchax, Aphanius,
• Biocide
• Bacillus thurningiensis H-14
• Advantages
• No chemical contamination
• Target specific
• Self dispersible into sites
• Briquette formulations

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INTEGRATED MOSQUITO MANAGEMENT (IMM)

• Implementation of a comprehensive plan of
  integrated approach in mosquito control is known
  as integrated mosquito management (IMM)
• ENTOMOLOGICAL SURVEYS VECTOR INDICES
• A good database on various aspects of mosquito
  dynamics can be generated by carrying out larval
  and pupae surveys and sampling of adult
  mosquitoes from landing/ testing collections
  using conventional standard techniques and newer
  software assisted methods like geographical
  information system (GIS) technology.

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Evaluation of Vector Control - by assessing
larval indices
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EMERGENCY MOSQUITO CONTROL

• 1. Institute public Information campaign to
  stress
• Basic epidemiological characteristics of
  DF/DHF
• Individual level measures to reduce risk of
  infection
• Use of house hold aerosol insecticides
• Source reduction efforts at home
  neighborhood.
• 2. Determine the extent of geographical area that
  requires insecticidal spraying by making
  serological confirmation of paired sera taken
  from presumptive cases of DF/DHF.
• 3. An inventory of the location, quantity and
  availability of pesticides and equipments for
  their application should be made.

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METHODS OF ENVIRONMENTAL MANAGEMENT
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Improvement of water supply and storage .

• 1. Potable water delivery in sufficient quantity,
  quality and consistency
• 2. Provide tight lids or screens - for storage
  containers
• 3. Design water storage containers to prevent
  ovi-position
• Solid Waste management
• Promote the basic Rule of 'Reduce" "Reuse,
  Recycle"
• Recycling /Disposal by incinerators, energy
  production plants, lime kilns
• Can be used in landfills, when cut into halves,
  shredded or chipped
• Modification of Man made Larval Habitats
• Employ "common sense approach to reduce the
  potential for Aedes mosquito to breed in and
  around human habitats.

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Management Actions for Control ofAedes Larval
Habitats
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Management Actions for Control ofAedes Larval
Habitats
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Management Actions for Control ofAedes Larval
Habitats
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Management Actions for Control ofAedes Larval
Habitats
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CHEMICAL CONTROL

• Larvicide application
• Perifocal Treatment
• Space Spraying
• Application Methods
• Larvicidal or "focal' Control
• Containers Holding Drinking Water
• I Temephos sand granules
• Methoprene - insect growth regulators
• B.T.I-biocide- Bacillus thuringiensis H-14 strain
• Perifocal Treatment - for Dam potable water
  containers Apply wettable powder or emulsifiable
  concentrate of Malathion Fenitrothion, Fenthion
  and Pyrethroids