THE TWO pronged approaches require for
malaria control and elimination with complex
and multi-faceted strategies are (1) activities
directed at mosquito parasite (plasmodium
falciparum) in the blood using drugs and
(2) activities directed at the malaria vector
(mosquitoes) through well designed vector
management techniques to prevent mosquitohuman
contact. Many of us have been
involved in mosquito management one way
or the other, consciously or unconsciously in
our life time. We have one time or the other
used insecticide sprays to kill mosquitoes and
mosquito coils to wade off mosquitoes from
our rooms and environments. Window netting
to prevent mosquito entry to our rooms is age
long practice to prevent mosquito-human
contact.
My friend nearly broke the front windscreen
of his car one day in an attempt to smash
mosquito in his car while driving. At another
time he almost lost control when he took his
two hands off the steering clamping them
with intention of smashing the mosquito
between his palms. There was this particular
occasion when my friend slapped himself
while we were sleeping in the night saying
he was killing a mosquito. Many friends
have being asking me the reason behind
mosquitoes waking them up by making
noise near their ears before or after sucking
their blood. There is this other friend that we
used to gather in his compound to relax after
a day’s hard work, by 6:30 to 7:30 pm in the
evening everybody would be clamping his
or her hands over their heads trying to kill
mosquitoes hovering above their heads. All
these self- protective behaviours are directed at
preventing mosquito- human contact. Other
mosquito management activities include
turning off collections of water in old plastic
containers, motor tyres and gutters; clearing
of bushes near the houses and application
of mosquito repellants on the body. All these
mosquito management activities discussed
above are carried out at the individual levels.
Malaria vector (mosquito) management
at the country/national levels are carried
out using integrated vector management
(IVM) approach. IVM becomes imperative
because malaria diseases result from the
interplay of the parasite, mosquitoes, human
and the environmental determinants. The
use of drugs alone cannot lead us to malaria
elimination. Integrated vector management
(IVM) is a rational decision making process for
optimal use of resources for vector control that
is characterized by evidence based decision
making and collaboration both within the health
sector and between other sectors. In IVM one
or multiple tools could be used to target many
vector borne diseases or multiple tools against
single vector borne disease.IVM approach
is a flexible management system that can be
designed and adapted to local conditions for
community participation. It however requires
strong political support and commitments that
would foster intra-intersectional collaboration
and streamlining decision making and resources
management. An effective IVM plan should
clearly outline the interventions, actors and mode
of resources coordination between the health and
other sectors including the communities, private
sector and non-health ministries like agriculture,
education, housing, and environment. The aim
of IVM is to make vector control more efficient,
cost effective, ecologically sound and sustainable.
A workable and implementable IVM strategic
plan should have:- integrated approach intraintersectional
collaboration layout evidence
based decision making outlook platform for
advocacy, social mobilization and legislation
room for capacity building
The following are the various IVM options/
strategies depending on the eco-epidemiological
and entomological characteristics of the
mosquitoes.
Environmental management: this consist
of modifications and manipulations of the
environment to deprive the mosquito population
of their requirements for breeding, resting and
feeding for survival Use of personal protection
measures: treated bed nets, treated curtains, eave
strips and repellants.
Indoor residual spray (IRS): this is house
spraying in areas where majority of the mosquito
population is endophilic and endophagic (resting
and biting indoor)
Space spraying: this is applied in areas where
majority of the mosquito population is exophilic
and exophagic (resting and biting outdoor) and
during the peak activities of the mosquitoes
Larviciding: this consists of the use of chemical
or biological agents to kill mosquito larvae if
the high population of the breeding sites within
mosquito flight range of community to be
protected can be located and are of manageable
size. Commonly used larvicides are biocides
produced by bacillus sphaericus and bacillus
thuringiensis isrealiensis. Some larvivorous fish
like gambusia affinis and poecilla reticulata feed
on mosquito larvae. Pesticides like temephos,
methoprene oils and monomolecular films are
larvicidal.
Safer and more sustainable alternative vector
control methods in addition to those mentioned
above are being developed to reduce the release
of insecticide into the ambient air and the residual
dust formation when treated bed net, area
spray and indoor residual spray (IRS) are being
employed. Some of the new technologies that
are currently being developed though not yet
certified by WHO are as follows;-
Insecticide-treated wall lining (ITWL; a
monofilament polyethylene insecticide treated
wall lining), durable lining (DL) and insecticidetreated
plastic sheets (ITPS). These are designed
to cover interior wall surfaces, utilizing a new
slow-release technology that combines the
advantages of LLINs and IRS, i.e., long-lasting
residual efficacy and no insecticide dusting. This
intervention acts against indoor-resting vector
populations, and remains active for between
3 and 5 years compared to IRS which has to be
applied annually or even more frequently. This
technology is being developed at the Institute
of Applied Materials (IAM) at the University
of Pretoria, Pretoria, South Africa. This new
development may overcome some of the
limitations presented by IRS while offering
constant indoor protection. The ITWL may
therefore be a potential safer and more sustainable
alternative to IRS.
Eave tubes technology; these are special tubes
with treated net mess at the end and are placed
horizontally at eave height. This package is
believed to impact overnight survival of hostseeking
mosquitoes and can suppress mosquito
population even in a complex environment.
Further studies are on going on this technology
Genetically modified mosquitoes; fighting
malaria using genetically engineered supermosquitoes
which if introduced into mosquito
population that transmit malaria would wipe
them out but they (modified mosquitoes) would
not transmit malaria. More studies need to be
done on this technique so that the world is not
exposed to new harmful mosquito species except
the modified mosquitoes are self-terminating
after finishing their job.
Mosquito electrocuting traps; these are
electronic devices used to trap mosquitoes in
homes and the surroundings.
The design of IVM implementation framework
should include comprehensive assessment of
resources needs, malaria situation in the country,
epidemiology, entomology, local determinants
of risks and stratification of risk areas. Though
malaria infection is holo-endermic in Nigeria,
the characteristics of the vector vary from the
north to the south as such there is the need
to conduct eco-epidemiological survey to
determine the behavior of the vector in the
various ecological settings across the country.
The outcomes of the survey and the assessment
will help in determining the resource needs and
in the selection of appropriate IVM potions.
Implementing IVM requires strong health system
with strong coordinating and management
system. There may be need to create or modify
the existing infrastructures, managerial
expertise and financial management system
to be able to effectively conduct IVM. The
health system will have to train, retrain and reorientate
both new and existing malaria control
programme officers. Rural communities need
to be trained and provided with information
on where and how the mosquitoes breed, rest
and transmit malaria parasite and on potential
interventions. They should be acquainted
with the skills needed to assist in undertaking
vector control. The malaria control staff
should seek the support of the local leaders
and community members from the planning
stage of IVM to the implantation phase taking
into consideration the perceptions, beliefs and
culture of the people.
Effective malaria vector control and
management is reliant on accurate information
and knowledge of local vector species,
their eco-epidemiological characteristics,
their susceptibility to insecticides as well as
vector and human behavior that may allow
the vectors to avoid control interventions.
Information on quality and type of housing,
availability of piped and irrigation water and
storage containers, location of dams, forest,
creeks and swamps near the settlements is
critical for effective IVM implementation.
Also important is information on the vector
breeding site, rainfall pattern, seasonal change
in vector density, host preference and their
nocturnal biting cycle. This information
is gotten through robust entomological
surveillance system which is divided into two
phases in IVM implementation programmes:-
Phase -1-; control phase – phases one
assessment is done through preliminary
surveillance, routine observation and
spot checks. This is done to determine the
following:-
Vector species
Vector resting and feeding habits
Breeding site
Vector density and longevity
Susceptibility to insecticides
Phase-2-; elimination phase – this phase
involved the following
Foci investigation – this is carried out to
determine and identify residual vectors, new
vectors and vector composition as well as
identifying the best approach for elimination.
Evaluation of the risk factors and malaria
re-introduction during elimination and post
elimination programme
The elimination phase surveillance involves
the measurement of the following:-
Human biting rate
Vectoral capacity
Entomological inoculation rate
Sporozote rate
For effective implementation of IVM, there is
the need for the establishment of national IVM
steering committee with broad participation
from various stakeholders and technical
working groups to feed the committees on
the day to day activities and progress of IVM
implementation. The national IVM committee
should be replicated at the states/zones/
regions and at the local government areas and
wards in the case of Nigeria. A robust IVM
strategic plan is a penance for effective IVM
implementation for measurable achievement
and outcomes.
Menyanga Abu
Development and Health system Consultant


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