VECTOR CONTROL
Dr. Khalid Rehman
MBBS, MPH, PhD.
Vector control interventions
A. Long Lasting Insecticide Treated Nets (LLINs)
B. Indoor Residual Spray (IRS)
C. Foggimg
D. Larviciding
E. Insecticide Treated Plastic Sheetings (ITPS)
F. Intermittent Preventive Treatement (IPTp)
G. Chemoprophylaxis
H. Treatment
I. Wall lining
The choice of a vector control
interventions depend on ???
Vector, its behavior
And
Context
Malaria control / Prevention
A. Long Lasting Insecticide Treated Nets (LLINs)
B. Indoor Residual Spray (IRS)
C. Fogging
D. Larviciding
E. Insecticide Treated Plastic Sheetings (ITPS)
F. Intermittent Preventive Treatement (IPTp)
G. Chemoprophylaxis
H. Treatment
I. Wall lining
Long Lasting Insecticide Treated Nets (LLINs)
WHOPES RECOMMENDED LLINS
TREATMENT
SUPPLIER NET MATERIAL INSECTICIDES
PROCESS
Sumitomo Chemical Polyethylene
Co. Ltd. Olyset Permethrin Incorporated to fiber
Vertergaard PermaNet 2. 0 and Polyester
Frandsen S.A. Deltamethin Coated
3.0
BASF South Africa Polyester
PTY Ltd. Interceptor Alphacypermethin Coated
Bestnet Europe Polyethylene
Limited Netprotect Deltamethin Incorporated to Fiber
Clarke Mosquito Polyethylene
DuraNet Alphacypermethin Incorporated to fiber
LLINs
Nets that have been treated with insecticide in the factory during
production, either coated or incorporated into the fibers.
Residual insecticide will continue to be effective for a period of 3 to 5
years.
LLINs do not need to be retreated.
LLINs are proven to withstand 20 washes before the insecticide becomes
ineffective.
Physical durability of the LLIN is variable depending upon living
conditions and type of LLIN.
As a public health professional-decision maker
WHAT DOES YOUR TARGET POPULATION LIKE?
What texture - each net have different mesh size, strength, rigidity
What colour do they like? - Blue, white, green, pink?? Blue tends to
be preferred.
What shape do they like? - square, round?
Do they care about durability?
Do they care about seeing the dying insects?
Advantages of Insecticide Treated Nets
If used correctly…LLINs provide significant personal
protection
Can reduce overall mortality rates by >20%
Can be set up on the move
Good quality netting material lasts up to 5 years
No need for retreatment if LLINs used
Disadvantages of LLINs
High start up costs - big initial investment
Logistically challenging
Educational component necessary!
Long lead times for delivery are common
They do not always fit the shelter
Resale is a problem
Commonly misused!
Political problems with distributions – very sensitive who gets
and who does not if you don’t have enough for everyone!
Indoor
Residual
Spray
Effective IRS
At least 85% of surfaces (homes) are sprayed to assure that the
majority of mosquitoes are exposed to the insecticide;
At least 85% of walls (2 metres high) are sprayed with insecticide
before the high transmission period (rainy season)
Disadvantages of Insecticide Residual
Spraying (IRS)
Time - Logistics
Material resources/cost
Access – during natural disasters/civil unrest can be difficult
People absent from homes during spraying
Dependent on skilled teams
Safety for handlers/sprayers
Impact variable depending on shelter materials
Fear of chemicals in communities
Field supervision & monitoring
ALL OF THESE CAN BE OVERCOME!!
•
Dengue Fever Control/Prevention
Public Health:
Vaccines (Dengvaxia)
Fogging
Larviciding
LLINs
Personal/community:
IEC / BCC.
Clothing to reduce exposed skin.
Insect repellent especially in early morning, late afternoon. Bed netting
is of little utility as Aedes bite during the day.
Environmental:
Reduced vector breeding sites
Treating vector breeding sites
Solid waste management
•
Fogging
Fogging: a mix of diesel
and an insecticide can be
effective for the control of
adult dengue vectors
Fogging-Requirements
Insecticide, appropriately diluted
Regular applications
Trained staff
Spraying equipment, protective gear, face masks
Equipment cleaning and maintenance,
Mapping and recording of sites treated
•
Fogging contd;
Treatment Cycle
For rapid reduction in vector density, space treatment should be carried
out every 2–3 days for 10 days.
Further applications once or twice a week to sustain suppression of the
adult vector population.
Precautions
When treatment is carried out with portable equipment, operators should
take special safety measures.
Protective clothing, face masks, operate the equipment for short periods.
Fogging- disadvantages / Issues
Expensive.
Needs special equipment
Dengue adults re-infest sprayed regions as
are very widespread
Possible role in crowded settings
Not effective on it’s own
Follow immediately with larvicide
Larviciding
Can be effective in controlling larvae, as a public health tool for
dengue control
•
Larviciding Requirements
Larvicide, appropriately diluted
Trained staff
Spraying equipment, protective gear may be
needed (depending on formulation)
Good documentation of larvicide used,
equipment cleaning and maintenance,
Mapping and recording of sites treated
•
•VBD Larviciding-Issues
Larviciding large or multiple water bodies is very expensive
and requires a large number of staff for potentially little impact
as breeding sites are so numerous
Water supplies in emergencies (particularly acute phases) are
rare, highly valued and breeding sites are multiple
Cultural issue with spraying/treating valued water sources
even when the chemical is harmless to humans
•
Environmental Management
Generally this means the elimination of
mosquito breeding sites.
Larviciding domestic water tanks and storage
pots places where rainwater collects or is
stored.
Rubbish clearance to remove other
mosquito breeding sites like car tyres, old
tins etc.
The covering of household water storage
containers.
•
Environmental management
If the area is large then a lot of human resource
needed and a huge operational cost.
Some breeding sites may also be the only available
water for the population.
Breeding sites for mosquitoes are extensive as they can
breed in the water left in a footprint!
•
IEC - BCC / Advocacy
Clear sites where mosquitoes breed:
Cover all household containers that hold water if
possible with insecticide treated materials
Remove or destroy containers where mosquitoes
breed
Proper waste disposal
Protect yourself from mosquito bites
Wear full clothing (long sleeves and pants) to minimize
the chance of being bitten by mosquitoes
Use mosquito repellants
Bed Nets are of little or no use for Dengue prevention
except for when children are sleeping during the day
•
How can messages be communicated
Mass media
• Radio, interviews
• TV
• Newspapers
Schools
Mosques
House-to-house campaigns
Posters, banners, events
FGDs
•
5 Pillars of Dengue Control Strategy
Provincial Health Resources
Departments
1. M=Man
2. M=Money
3. M=Machinery
Operational Research
Case Management
Surveillance
Vector Control
4. M=Material
Awareness
5. M=Management
Community
NGOs District Health Hospitals
Insecticide Plastic Sheetings (ITPs)
Wall Linings
Wall lining
