Water Management for Disease Vector Control - Biological and Environmental Control of Disease Vectors - page 163

mostly through mass drug-administration
programmes; therefore, the contribution of
water management towards their control is
likely to be limited. Dengue is a vector-borne
disease, transmitted by aedine mosquitoes, and a
major emerging public health problem. The
control of aedine mosquitoes may involve water
management, but only at the household and
community level, including managing domestic
water supplies, reducing accumulation of
seepage water from leaking water pipes, and
emptying discarded plastic containers and other
abandoned items that provide larval habitats in
urban areas.
Numerous case studies have described the
association between vector-borne diseases and
irrigation development, especially rice irrigated
agriculture (Mather and That, 1984;
Amerasinghe and Ariyasena, 1990; Diuk-
Wasser et al ., 2007). Studies have found that,
although irrigation systems present an
enormous aquatic habitat for disease vectors,
the degree to which they infl uence the
proliferation of potential vectors depends upon
the ecology of the local vector population,
cropping pattern, the system design and the
management of vegetation and water in the
irrigation and drainage canals (FAO, 1987;
Oomen et al ., 1990). Although many studies
have assessed the links between water resources
development (e.g. irrigation development, dam
construction and large drainage programmes)
and human health, only a few studies have
assessed the feasibility of changing water
management practices and its impact on the
transmission of vector-borne diseases.
Three outstanding examples of water
management for malaria vector control
interventions that were implemented in the
period 1900-1950 in South Asia have been
described by Konradsen et al . (2004): (i) a range
of engineering methods for vector control
activities were tested in Mian Mir, an arid area
with large-scale irrigation in current day
Pakistan; (ii) drainage and landscaping were
used for malaria control at Klang and Port
Swettenham in Malaysia; and (iii) in Sri Lanka,
stream water fl ows were managed for the
prevention of malaria. Other historic high profi le
cases in which engineers played a key role in
reducing malarial disease through water
management come from the construction of the

Panama Canal and the Tennessee Valley
Authority in the USA. In the Tennessee River
Basin, following the preparation of a clear
shoreline and the embankment of shallow
areas, the water level of the main reservoirs was
subjected to periodic fl uctuations to strand
mosquito larvae. Changing the water levels in
reservoirs was also an ef ective method for snail
control in Puerto Rico (Jobin, 1973). Several
other water management strategies for
schistosomiasis control have been described,
including the removal of vegetation from the
banks of irrigation canals, concrete lining of
irrigation canals and increasing the fl ow velocity
in irrigation canals to dislodge the snails
(Chandiwana et al ., 1988; Oomen et al ., 1990).
A number of topics and guidelines have been
produced aimed at assisting the integration of
vector control measures and, in particular,
water management practices into development
projects. These include a comprehensive
approach for the planning and design of
irrigation systems presented by Oomen et al .
(1994) and a series of reports published by the
WHO/FAO/UNEP Panel of Experts on Environ-
mental Management for Vector Control (PEEM)
(IRRI/PEEM, 1987).

9.2 Vector-borne Diseases and
Aspects of Vector Ecology of
Relevance to Water Management

9.2.1 Malaria

Malaria, and its association with irrigated
agriculture and dam construction, has been
extensively reviewed (Bradley, 1977; Mather and
That, 1984; Service, 1984, 1989; Lacey and
Lacey, 1990; Keiser et al ., 2005b). Studies in
Africa and Asia have shown that the malaria-
irrigation linkages are complex and situation-
specifi c, with greater or lesser impacts on malaria
transmission depending upon local conditions
and vectors (Ijumba and Lindsay, 2001;
Amerasinghe, 2003). In some places in Africa
and Asia, irrigation development has resulted in
increased malaria transmission. For example, in
Ethiopia, prevalence of malaria parasites was
associated with small-scale irrigation
development (Kibret et al ., 2010) and in the Thar
Desert, in India, the introduction of a large-scale