Water & Health
African dams linked to one million malaria
cases a year
to the study which was published in the Malaria Journal
last month (4 September).
Alex Awiti, an ecosystems ecology expert at the Kenyabased Aga Khan University, says stagnant water of any
kind, in puddles or lagoons provides suitable habitat for
mosquitoes.
“What is new is that this study now shows the scale or
magnitude of the problem,” he tells SciDev.Net.
Copyright: William Daniels/Panos
Large dams contribute to more than one million malaria
cases in Sub-Saharan Africa a year, a study says.
According to scientists from Australia, Laos and South
Africa who conducted the study, the cumulative effect of
large dams on malaria has not been known despite the
construction of many dams on the continent.
Governments, he says, have no excuse for not providing
bednets, undertaking regular indoor spraying and ensuring
that test kits are available at local clinics or pharmacy
outlets to ensure timely diagnoses and treatment.
Awiti says this study presents evidence at scale of the
potential trade-off between the positive economic benefits
of dams and human health consequences.
“We are faced with trade-offs all the time. Nevertheless,
the choices are clear. We must think about approaches to
control malaria transmission whenever large dam projects
are implemented,” Awiti adds.
Source: SciDev.Net
Therefore, they mapped the distribution of 1,268 large
existing dams and 78 large planned dams in relation to
malaria transmission across all countries in Sub-Saharan
Africa.
Legionella (Legionnaires’ Disease and
Pontiac Fever)
Jonathan Lautze, a co-author of the study and a researcher
at the International Water Management Institute Southern
Africa office in Pretoria, South Africa, says they collected
and quantified the cumulative malaria impact of large
dams in Sub-Saharan Africa, documented the relative
effect of dams in zones of different stability of malaria
transmission and determined the distribution of dams in
relation to these zones.
Causes and Common Sources of Infection
Causes and Transmission
Legionella is a type of bacterium found naturally in fresh
water. When people are exposed to the bacterium, it can
cause illness (Legionnaires’ disease and Pontiac fever). This
bacterium grows best in warm water, like the kind found
in
Lautze explains that the study shows large dams are
contributing substantially to malaria in the region, and that
the resulting aggregate number of malaria cases of more
than a million requires greater focus.
“Given the likelihood of more dam construction in Africa
in the coming years, it is increasingly important that
adverse malaria impacts of dams are addressed,” he says,
noting that the study provides a strong rationale for greater
emphasis on mitigating dam-associated malaria.
The study’s findings could help development agencies
and health specialists who may wish to prioritise malaria
control efforts, he adds, noting that some revenue from
hydropower-related dams could be redirected toward local
mitigation efforts.
Legionella are NOT spread from one person to another
person.
• Hot tubs
• Cooling towers (air-conditioning units for large
buildings)
• Hot water tanks
• Large plumbing systems
• Decorative fountains
While the number of existing and planned dams for which
locations could be found was below the known total of
each, the set of existing and planned dams mapped for this
study is the most extensive yet used in an analysis of the
malaria impacts of dams in Sub-Saharan Africa, according
Cooling towers use water to remove heat from a process
or building. They are often part of the air conditioning
systems of large buildings. In contrast, home and car air
conditioning units do not use water to cool, so they do not
aerosolize water (spread small droplets of water in the air)
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Africa Water, Sanitation & Hygiene • November - December 2015