Integrated vector control approach Dr Kulrajat Bhasin.
Integrated vector control
Dr. Kulrajat Bhasin
Plan of presentation
Principles of vector control
Integrated vector control approach.
Selection criteria for vector control measures
Evolution of Integrated vector control approach.
Integrated vector control approach for mosquito.
Key elements of an IVC Strategy.
• Vector - definition
• Common vectors and diseases
- Mosquito : Malaria, filaria, viral encephalitis e.g.., Japanese
encephalitis, viral fevers e.g.., Dengue, west Nile.
- Housefly : typhoid and Para typhoid fever, diarrhea, dysentery,
cholera, gastroenteritis, amoebiasis, helminthic infestations,
poliomyelitis, conjunctivitis, trachoma, anthrax, etc.
- Sand fly : Kala azar, oriental sore, sand fly fever, oraya fever
• Transmission of disease- Direct contact, mechanical, biological
(propagative, cyclopropagative, cyclodevelopmental).
Principles of vector control
1. Environmental control: the best approach as
the results are likely to be permanent.
2. Chemical control
3. Biological control
4. Genetic control
5. Newer methods like insect growth regulators,
Integrated vector control approach
• No single method is likely to provide a solution in all situations. The
present trend is to adapt a IVC approach.
• Vector control approach combining two or more methods with a
view to obtain maximum results with minimum efforts.
• “Integrated vector control approach is the present trend for vector
control defined as utilization of all appropriate technological and
management techniques to bring out an effective degree of vector
suppression in a cost effective manner and also to avoid the
overuse of one of the methods”.
• Selection of methods is not possible without detailed field
information on the ecology, bionomics of vectors, role in disease
Life cycle of Mosquito
4 Common stages in development namely : 1. Egg, 2.Larva ,
3.pupa and 4. adult
Habits of vectors
A knowledge of these habits is essential from the point of view
of controlling them as well as the part they play in transmission
males never bite and subsist on plant juices
females on the other hand are
2. Time of biting: generally evening (aedes
3. Resting habits: exophyllic . Vegetations, shrubs
, tree holes, cattle sheds.
4.Breeding habits: anopheles-prefer clean water
culicines - dirty polluted water.
aedes - artificial collections of water( rainy
mansonia – aquatic plants( water hyacinth
5. Hibernation: in winters or when condns not
favorable in adult stage
6. Dispersal : not far unless swept away with air
currents( yellow fever)
7. Life span : normally varies from 8 – 34 days but
males as a rule are short lived
Breeding habits : in order of importance are
Fresh horse manure
Manure of other animals
Decaying fruits and vegs
Organic rubbish dumps
Liquid wastes scattered on ground
Feeding habits : does not bite, mechanical
transmission. Cannot eat solid food so vomits
and making a soln sucks in a liquid state
Restlessness : moves to and fro.
Vomit drop : fly vomits frequently which is a
culture of disease agents
Defecation : habit of defecating depositing
bacteria on exposed food
Resting habits : on vertical surfaces and
hanging objects and tendency to fly towards
Dispersal : up to 4 miles or more from point of
Selection criteria for vector control measures
3. Simplicity of use- indications, contraindications,
skills, difficulties in using.
5. Time and effort
6. Type of benefit.
7. Social acceptability- local context.
8. Support requirements.
Evolution of the integrated vector control
• Vector control has been a part of malaria control activities
since the early 20th century.
• During the pre-DDT era, reduction of vector mosquitoes
largely relied on larviciding & environmental management of
• 1950s- DDT and other insecticides were extensively used.
• 1970s, development of insecticide resistance, poor human
acceptance and environmental concerns against the use of
• This led to a rethinking in vector control strategies.
• 1980s, WHO proposed an Integrated Vector Control (IVC)
strategy based on the principles of Integrated Pest
Management in agriculture.
Integrated vector control approach for mosquito
Mosquito Control Measures
Environmental 1. Space sprays
3. Genetic control
3. Biological control
1. Mosquito nets
The most important step in reducing the number of mosquitoes
1.Elimination of breeding places (source reduction) like,
Filling and leveling
Drainage of breeding places
2.Proper disposal of refuse other wastes.
3.Cleanliness in and around the houses .
Community involvement & multisectoral
Highly toxic to insect larvae or pupae, interfering with
development into adults. Used in large scales in USA..
• Costly & have restricted availability -not used in India.
Particularly useful if insects have developed resistance to
insecticides or because of their environmental effect.
Safe to human beings and environment.
1. Juvenile hormone analogues: prevent development of larvae
into pupa or pupae into adult. Ex. Methoprene
2. Chitin synthesis inhibitors: interfere with moulting process,
killing larvae when they moult. Act more rapidly.
Ex. Diflubenzuron and Triflumoron.
• Expanded form of polystyrene granules - available commercially
with diameter ranging from 0.6 to 2.5 mm.
• Increased by boiling.
• They do not decay and remain floating for years.
• Spread on surface of water to form floating layer. A layer of 1-2
cm is sufficient if it covers the surface.
• Easily blown or washed away- only sites where water remains
• Used safe in drinking water
Natural enemies into the environment-includes Insects,
Viruses, Bacteria, Protozoa, Fungi and Fish.
Only two of them have become widely employed. They are
Larvivorous fish and Biolarvicides.
• Feed on mosquito larvae.
• Easy, practical, cheap; they have no food value.
• They should have the following characteristics
– Preference for mosquito larvae over other types of food
– Small size
– High reproduction rate
– Tolerance to pollution, temperature fluctuation &
• Two species are widely usedGambusia - clean water, tolerate wide range of temperature, pH
Guppy- Polluted water, cannot <10 degree C.
• Useful in ornamental tanks, wells, Garden ponds, fountains,
swimming pools, large water collection.
• Approximately 5 fish per sq.m of water surface.
a. Long term effective control measure.
b. Cost effective.
c. Environmentally safe.
d. Controls variety of mosquito species.
a. Effective when large numbers eventually establish themselves.
b. takes 1-2 months; not suitable - quick anti larval measures are
c. less effective in waters with much vegetation or floating garbage.
Bacteria for the control of mosquito larvae. Bacillus
thuringiensis H 14 and Bacillus sphaericus.
• Available as wettable powder and granules which contain
bacteria, spores and toxic crystals.
• Safe to environment , human being and animals but are
Bacillus thuringiensis H 14
• Gram positive, spore forming bacteria which is specifically
acts against mosquito larvae.
• Produces endotoxin which after ingestion causes gut
paralysis & leakage of contents into body cavity leading to
It is applied at 0.5 gm/sq.m
250gm of B. thuringiensis is mixed with 10 L of water to make
2.5% suspension & sprayed at 1L over 50 sq.m every 2 weeks.
• It also produces toxin.
• It is more effective in polluted water - suitable for treatment
of breeding sites of Culex.
• 500gm of B. sphaericus with 10 L of water to make 5%
suspension & it is sprayed at 1 L over 50 sq.m. every 3 weeks.
Others BiolarvicidesFungi- Coelomyces, Culicinomyces,
Nematodes – Romanomermis cluicivorax and R. iyengari.
– Space sprays are those where the insecticidal
formulations is sprayed into the atmosphere in the form
of mist or fog.
1. Thermal fog.
2. ULV cold aerosols.
– Done where immediate results are needed like during
outbreak of disease to bring down mosquito population
– Exophillic vector species.
Space sprays (contd)
1:19 i.e., 1 part of
extract in 19 parts
Flit pump or hand
5 parts of
95 parts of
Speed of vehicle 6
Deltamethrin 1 litre in 199
Advantages of space sprays
• Immediate effect - suitable for control of disease outbreak.
• Less insecticide is required for one application.
• Kills exophillic species of mosquito.
Disadvantages of Space sprays
• Effect lasts for shorter period- repeated at least once a week.
• The cost of equipment, operational and maintenance - high;
• Needs specially trained staff for maintenance and repair.
• May cause pollution.
• Problems with acceptability.
Indoor Residual Sprays
• Application of insecticides to surfaces so that the insecticide
particles remain on the surface in the form, size and quantity
suitable for insects to pick up on contact and sufficient to
exert a lethal effect over a long period.
• Endophillic species.
Compression pneumatic sprayer
1. May leave visible deposits on walls .
2. Non acceptability.
3. Painting or re-plastering of walls after application reduces or
eliminates efficacy of insecticides.
4. People may be reluctant to allow stranger into their houses.
• Methods such as
sterile male technique
1. Lack of mating competitiveness released males.
2. Immigration of fertile females from regions close to the release
Reallocation or introduction of cattle or domestic animals
between settlements and mosquito breeding i.e. ring of
cattle sheds on the outskirts of a village with houses in the
Many mosquito prefer animal blood than human blood and
hence decreases biting of human and transmission of
• In Japan it is proved to be effective against Culex.
a. Mosquito Nets
Mosquito bite during sleep. They also protect against other
creatures like spiders, cockroaches, lizards and rats.
• Best pattern is rectangular net.
• Size of the openings in the net is should not exceed 0.0475
inch in any diameter. The number of holes in one square inch
is usually 150.
Disadvantages of Untreated Nets
1. Mosquito can feed when body makes contact with the net.
2. Hungry mosquito wait on or near the net until net is opened.
3. After failing to get through the net Mosquito are diverted to
unprotected people sleeping nearby.
Insecticides Treated bed Nets
Provide better and effective protection by not only
preventing mosquito bites & also killing them.
They are prepared by soaking the net in insecticidal solution
Nylon nets are preferred - more durable, insecticide stays
longer duration and quicker in drying after impregnation.
are used for impregnation.
Permethrin,Deltamethrin, Cyfluthrin and Lambdacyhalothrin
• Mainly used for application on exposed parts of skin.
• They act by preventing human-insect contact and do not
knock down or kill.
• Chief advantage is short duration of protection. Useful for
Plantation workers, Army people, Labors who work outdoor
at night and Travelers.
• N-N-Diethyl-3-toluamide (DEET),indalone, dimethyl pthalate,
• DEET is best available product; effect last for 4-6 hours. on
c. Screening- Screening of buildings with zinc, aluminum, plastic or
bronze having 16 meshes to the inch is recommended.
d. Protective clothing.
d. Others- Mosquito hitting swatter, use of fan at high speed,
Protect against mosquito and biting flies by,
1. Irritating and disturbing them after contact and preventing
them from biting and also preventing them entering room.
2. Paralyzing or killing them.
Coils, mats, liquid vaporizers and aerosols/spray- Transfluthrin,
• Use of laws to prevent / reduce propagation and spread of
vectors is an effective means of vector management, through
•Water level management
•Exotic natural enemies
Bed nets and repellents
Key elements of an IVC Strategy
Advocacy, social mobilization and legislation
– Promotion and inclusion of IVC principles.
– Empowerment of communities for sustainability.
– Establishment or strengthening - regulatory & legislative
control for public health.
2. Collaboration within the health sector and other sectors:
– Agriculture and agriculture development projects.
Infrastructure development projects;
Water resources development projects;
3. Integrated approach
• IRS in high risk areas and in epidemic situations based on
vector behavior and community acceptance.
• Use of insecticide-treated nets/long-lasting insecticidal nets
and other personal protection methods.
• Environmental management.
• Biological control.
4. Evidence-based decision making
• IVC strategy requires assessment of the vector control needs
based on the local factors.
• Demands efficient surveillance/ information management
system that highlights targets for vector control interventions.
5. Operational and implementation research
• Strong operational and implementation research support for
development of new and modified tools
6. Capacity building
• expertise at the central, as well as peripheral levels.
• developing tools and guidelines in local languages and training
of personnel for vector control.
7. Monitoring and evaluation
• indicators as per the local requirements and targets set.
• Inputs, costs & outcome of different interventions, when used
singly or in combination & simultaneously or consecutively in a
defined area, must be monitored.