Engineering and malaria control: Learning from the past 100 years
Abstract
Traditionally, engineering and environment-based interventions have contributed to the prevention of malaria in Asia. However, with the introduction of DDT and other potent insecticides, chemical control became the dominating strategy. The renewed interest in environmental-management-based approaches for the control of malaria vectors follows the rapid development of resistance by mosquitoes to the widely used insecticides, the increasing cost of developing new chemicals, logistical constraints involved in the implementation of residual-spraying programs and the environmental concerns linked to the use of persistent organic pollutants. To guide future research and operational agendas focusing on environmental-control interventions, it is necessary to learn from the successes and failures from the time before the introduction of insecticides. The objective of this paper is to describe the experiences gained in Asia with early vector control interventions focusing on cases from the former Indian Punjab, Malaysia and Sri Lanka. The paper deals primarily with the agricultural engineering and land and water management vector control interventions implemented in the period 1900-1950. The selected cases are discussed in the wider context of environment-based approaches for the control of malaria vectors, including current relevance. Clearly, some of the interventions piloted and implemented early in the last century still have relevance today but generally in a very site-specific manner and in combination with other preventive and curative activities. Some of the approaches followed earlier on to support implementation would not be acceptable or feasible today, from a social or environmental point of view.
Acta Tropica 89 (2004) 99–108
Engineering and malaria control: learning from the past 100 years
Flemming Konradsen
a,b,∗
, Wim van der Hoek
a
, Felix P. Amerasinghe
a
,
Clifford Mutero
a,c
, Eline Boelee
a
a
International Water Management Institute (IWMI), P.O. Box 2075, Colombo, Sri Lanka
b
Department of International Health, Institute of Public Health, University of Copenhagen,
Panum, Blegdamsvej 3, 2200 Copenhagen, Denmark
c
CGIAR Systemwide Initiative on Malaria and Agriculture (SIMA), IWMI, Private Bag X813, 0127 Pretoria, South Africa
Abstract
Traditionally,engineeringandenvironment-basedinterventionshavecontributedtothepreventionofmalariainAsia.However,
withtheintroductionofDDTandotherpotentinsecticides,chemicalcontrolbecamethedominatingstrategy.Therenewedinterest
in environmental-management-based approaches for the control of malaria vectors follows the rapid development of resistance
by mosquitoes to the widely used insecticides, the increasing cost of developing new chemicals, logistical constraints involved
in the implementation of residual-spraying programs and the environmental concerns linked to the use of persistent organic
pollutants. To guide future research and operational agendas focusing on environmental-control interventions, it is necessary
to learn from the successes and failures from the time before the introduction of insecticides. The objective of this paper is
to describe the experiences gained in Asia with early vector control interventions focusing on cases from the former Indian
Punjab, Malaysia and Sri Lanka. The paper deals primarily with the agricultural engineering and land and water management
vector control interventions implemented in the period 1900–1950. The selected cases are discussed in the wider context of
environment-based approaches for the control of malaria vectors, including current relevance. Clearly, some of the interventions
piloted and implemented early in the last century still have relevance today but generally in a very site-specific manner and in
combination with otherpreventive and curative activities. Some of the approaches followed earlier onto support implementation
would not be acceptable or feasible today, from a social or environmental point of view.
© 2003 Elsevier B.V. All rights reserved.
Keywords: Malaria; Environmental-management; Vector control; Water management; Punjab; Malaysia; Sri Lanka
1. Background
As early as the sixth century b.c. the Greeks and
the Romans were aware of the association between
fevers and stagnant waters and swamps. This aware-
ness led to drainage interventions aimed at improving
∗
Corresponding author. Tel.: +45-35-32-7776;
fax: +45-35-32-7736.
E-mail address: f.konradsen@pubhealth.ku.dk (F. Konradsen).
the health of the nearby population and increasing
agricultural production (Gilles and Warrell, 1993).
Later, other communities throughout much of Eu-
rope took up deliberate drainage activities focusing
on improvements in public health. However, not un-
til many centuries later, with the discovery of the
role of mosquitoes as the vector of malaria in India
in 1897, were engineers provided with a scientific
basis for designing specific interventions to con-
trol malaria. Some of the high profile cases where
0001-706X/$ – see front matter © 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.actatropica.2003.09.013
100 F. Konradsen et al. / Acta Tropica 89 (2004) 99–108
engineers played a key role in reducing malarial
disease through environmental-management inter-
ventions come from the construction of the Panama
Canal and the drying of the Pontine marshes in
Italy where land filling and drainage played an im-
portant role. Also, the water-management activities
of the Tennessee Valley Authority in the USA are
prime examples of the systematic application of
environmental-management measures for the preven-
tion and control of malaria (Rafatjah, 1988; Hinman,
1941). Many less well-known examples exist where
engineering and environment-basedinterventionshave
played an important role in the prevention of malaria.
One such example from Africa has recently been de-
scribed in detail by Utzinger et al. (2001). Most of
these examples come from the first half of the 20th
century before DDT and other potent insecticides be-
came available and chemical-based vector control be-
came the dominating strategy, and engineering-based
interventions lost their importance. The renewed in-
terest in environmental-management approaches for
the control of malaria follows the rapid development
of resistance to the insecticides by mosquitoes, the
increasing cost of developing new chemicals and
the logistical constraints involved in the operation of
chemical-vector control programs. Similarly, environ-
mental concerns raised over the use of persistent or-
ganic pollutants have made national governments and
international organizations more interested in looking
for alternative measures to control malaria vectors.
In recent strategies, the World Health Organization
(WHO) has advocated the use of a multitude of inter-
ventions in the control of malaria. As such, engineer-
ing and environmental-control measures may again
become an important part of vector-control initiatives.
This paper describes three cases that highlight early
experiences with using agricultural engineering and
land and water management for the control of malaria
vectorsin Asia. The objectiveof ongoing effortstorev-
iew the literature from the period 1900–1950 is
to identify those experiences that are of current
relevance.
2. Methodology
The study was based on the identification of re-
search reports published primarily in the period 1900
to 1950 in the form of original articles, research let-
ters, reviews or government commissioned technical
reports. The publications have been identified through
a manual search of all publications listed in annual ref-
erence books of Index Medicus; the index catalogues
of the Library of the Surgeon General’s Office of the
US Army and catalogues of the National Library of
Medicine in the USA. An electronic search was also
performed on the Medline database to identify review
papers of relevance for the 1900–1950 period. Text-
books on malaria control and WHO publications were
reviewed to identify additional relevant publications
that may not have been included in the main reference
systems used for the review. The search was guided by
the use of selected key words including: Anopheles,
mosquitoes, vector control, malaria, malaria eradica-
tion, fever, black water fever, tropical disease control,
and sanitary engineering. Relevant publications in
English, German, Dutch, Danish and Swedish were
requested from central libraries located primarily in
the UK, Denmark, USA, and India. More than 60 orig-
inal published papers were identified. Only limited
emphasis was given to publications from the Dutch
East Indies (Indonesia), since these have been covered
by Takken et al. (1990). When reviewing the early
documentation on environmental-management for
malaria control in Asia, the experiences at Mian Mir
in Punjab and at Klang Town and Port Swettenham in
Malaysia stand out. These two cases were reported on
and discussed intensively among the malaria-research
community in the early part of the 20th century
resulting in more than 20 research and technical
references.
3. Malaria-vector control interventions
3.1. The experiences from Mian Mir: vector control
in an arid area with large-scale irrigation
Mian Mir, today a suburb of Lahore, was selected
as an experimental site for anti-larval operations in
1901 with the backing of the newly established Royal
Society Malaria Committee (Christophers, 1904;
Bynum, 1994). The interventions to be tested at Mian
Mir were partly based on the results of preliminary
anti-mosquito efforts that were undertaken in Free-
town, Accra, and Lagos in west Africa around the
F. Konradsen et al. / Acta Tropica 89 (2004) 99–108 101
turn of the century (Stephens, 1904). The interven-
tions were also inspired by the vector-control activ-
ities initiated in Ismailia, Egypt, by the Suez Canal
Company under the guidance of Ross (Boyce, 1904).
Christophers (1904) and Stephens (1904) identified
three different areas of interventions drawing upon the
earlier control experiences from outside India. These
interventions were the systematic use of quinine as
a prophylactic, the reduction of anopheline breeding,
and the segregation of Europeans from the local in-
habitants (Bynum, 1994). However, much of the early
fieldwork at Mian Mir focused on the identification
of breeding sites and mosquito reduction under the
guidance of James (1903a,b).
The settlement at Mian Mir included an army gar-
rison and scattered traditional residential and farming
areas. The area was characterized by flat terrain and
a soil that was, for the most part, impervious to wa-
ter after one or two hours of rain, together resulting in
limited natural drainage. The storm-water drains that
were in place in the area were without sufficient fall
and seemed to do more harm than good. Although the
area was arid, even the slightest shower of rain would
result in surface puddles until dried up by the sun.
Another feature of the area was the irrigation network
of shallow channels from which farmers drew water
by means of Persian wheels to irrigate field crops and
home gardens. Extensive baseline investigations were
carried out to assess the level of malaria in the area,
describe seasonal differences in transmission and to
identify important breeding sites for the mosquito vec-
tor (Christophers, 1904). A special focus of the inves-
tigation was the burden of malaria among the army
personnel and the breeding within the vicinity of army
barracks. The entomological investigations, including
dissections, led to the conclusion that Anopheles culi-
cifacies was the only vector of importance for malaria
transmission in Mian Mir and this had a great influ-
ence on the design of specific interventions (James,
1903a). The vector was found to breed extensively in
the smaller irrigation channels (water courses), espe-
cially where vegetation along the edges reduced water
velocity or during periods of canal closure when pools
were formed in the channels. During specific peri-
ods the small shallow canals would overflow creating
breeding opportunities along the channels. The poorly
designed and maintained small earthen drains were
other important breeding sites. The practice of pro-
viding excess irrigation water to small gardens imme-
diately surrounding homesteads created breeding op-
portunities too. The baseline investigations indicated
that the seasonal pattern of malaria was related to rain-
fall, temperature and irrigation water releases. Also,
it was found that the army quarters closest to the irri-
gation canals had the highest risk of malaria (James,
1903a,b).
Early measures implemented to reduce vector
breeding at Mian Mir included repairing the banks
of irrigation channels and clearing these of silt and
vegetation to reduce overflow. Additionally, depres-
sions next to channels were reduced by levelling. The
ten shallow canals closest to the army barracks were
inspected daily during the active breeding season and
debris removed and attempts made to reduce pooling.
If the weekly inspection of the garden sections of the
army compound found suspected anopheline breed-
ing pools these were emptied and filled with earth, as
much as possible. During the rainy period, June and
July, great efforts were made to reduce the breeding
potential of the often quite large pools formed in
drains either by using buckets to empty the pools or
by applying kerosene oil (Christophers, 1904; James,
1903b). However, the application of oil on suspected
breeding sites showed limited effect due to evapora-
tion in the hot climate (Bynum, 1994). Continuous
inspection of housing areas resulted in the identifica-
tion of potential breeding sites, e.g., domestic water
containers, and these were dealt with. Small surface
drainage lines were also created to remove water
from larger open areas and more than 250 larger soil
depressions were permanently filled. In addition to
the environmental modifications and manipulations
undertaken in the area, mass distribution of quinine
was practiced (Christophers, 1904; James, 1903b).
The actions taken during the first year of operation at
Mian Mir were very labour intensive. For example, for
the removal of vegetation from irrigation canals fifty
labourers (“coolies”) were assigned (Bynum, 1994).
The Mian Mir case gave rise to a heated debate
over the role of irrigation in the spread of malaria
and how to combine the necessity of food produc-
tion and livelihoods with public health (Giles, 1904;
Anonymous, 1910). Based on the surveys and expe-
riences documented during the first year of work at
Mian Mir the discussion centred round the question
of whether malaria could ever be controlled without
102 F. Konradsen et al. / Acta Tropica 89 (2004) 99–108
abandoning the irrigation system or at least chang-
ing the way the water was managed throughout the
canals (Sewell, 1905; Bynum, 1994). Partly as a re-
sult of the debate the final years of work at Mian Mir,
from 1904 to 1909 emphasized the filling in of irriga-
tion canals, extensive land levellingactivitiesand more
permanent surface and sub-surface drainage (Bynum,
1994).
The anti-larval measures implemented at Mian Mir
had an effect on larval breeding for the specific habi-
tats covered but the effect on adult mosquito abun-
dance within the settlements was limited. For the early
phase of the control efforts no clear conclusion could
be reached as to what effect the vector control inter-
ventions actually had on malaria (James, 1903b). In
1909, the Government of India appointed a committee
to investigate the experiences at Mian Mir and came
up with a general negative finding as to its effective-
ness on reducing malaria. Ross (1910) made several
contributions to the discussions on Mian Mir and he
claimed that the committee did not have sufficient ba-
sis for its conclusions and felt strongly that the expe-
riences of Mian Mir should not determine the future
of vector control for all of India. Earlier, Ross and
others had been very critical of the design followed at
Mian Mir and claimed that not enough had been done
to prevent vector breeding over a sufficiently large
area to actually measure a reduction in vectors within
human habitations (Ross, 1904a,b). Also, Ross found
the investments in anti-larval control too limited and
completely out of proportion with the cost of malaria
to the government. When considering the cost to the
government from the sick soldiers at Mian Mir alone
the expenditure for malaria prevention was less than
1% of this cost (Ross, 1910). In 1924, following a
visit to Mian Mir, Watson (1924) concluded that the
area was never sufficiently drained and proper out-
lets should have been constructed from the drainage
canals, possibly with pumping devices, to assist the
drying of the entire area, including the drains. It also
gave rise to some of the fundamental questions for ef-
fective malaria vector control, i.e., how large an area
should be covered to have an effect on the protection
of human settlements and how much reduction inadult
vector population will have to be achieved to have an
impact on human malaria? The cost-effectiveness of
proposed interventions was central in the debate of the
Mian Mir experiences.
The heated debate resulting from the Mian Mir ex-
periences was partly a result of the personalities in-
volved (adequately discussed in Bynum, 1994). How-
ever, the debate was also a reflection of the fact that
the early optimistic statements by Ross (1899) on the
great potentials of malaria control through targeting
specific mosquito breeding sites was seriously ques-
tioned through field-based activities in a complex eco-
logical site such as Mian Mir where multiple breeding
habitats made mosquito larval control an often unman-
ageable task.
3.2. The effect of drainage and landscaping in
malaria control at Klang and Port Swettenham
Around the same time as the start of the Mian
Mir project malaria-control activities were initiated in
Malaysia. The cases from Malaysia are examples of
government officials reacting rapidly to the new av-
enues for control that were made possible by the dis-
covery of the role of mosquitoes in the transmission
of malaria.
In 1901 Klang was a town of around 3500 people,
located in hilly terrain along the Klang river in one of
the most important rubber and coffee cultivation areas
of Malaysia. The area experienced severe problems
with malaria, resulting in government officials and
labourers being continuously ill and unable to work
(Watson, 1905). From early on Watson kept records of
the residence of each malaria case that came into con-
tact with the hospital services to assess the geograph-
ical distribution in relation to, for example, potential
mosquito breeding sites and to separate imported cases
from indigenous ones. Following his early reconnais-
sance Watson assessed that the Chinese population of
Klang would refuse to take quinine as a prophylactic
and he also considered it impractical to use bed nets
or house screening because of the expected difficulties
with supervision. He decided that an engineering ap-
proach would be the most feasible, especially building
a drainage infrastructure (Bradley, 1994). Entomologi-
cal surveys in Klang found that the permanent swamps
in and around the town and the large number of open
wells and pools along the road provided breeding op-
portunities for anopheline mosquitoes. Surveys later
identified A. umbrosus as the main vector. Ground-
water was very high at the foot of the small hills
surrounding the town and this created flooded condi-
F. Konradsen et al. / Acta Tropica 89 (2004) 99–108 103
tions following rains (Watson, 1903, 1924). The first
activities undertaken with the assistance of govern-
ment departments and private landowners were to re-
move dense jungle vegetation and undergrowth from
within and immediately around the town. Most of the
swamps within the town were also filled or drained.
Large-scale drainage systems were put into operation,
based on the construction of concrete turf-lined in-
verts. This kind of drain was found to be relatively
inexpensive and the turf sides facilitated water inflow
from the subsoil. Open drains that followed the con-
tour of the hill at its lowest point were constructed
along the foothills (Watson, 1903, 1924). The idea be-
hind this was to capture the water from the springs
and surface runoff before it could accumulate on the
plains outside the town. Within a few years, the entire
town perimeter was drained, with the cost primarily
covered by the state and, to a lesser extent, by pri-
vate landowners and private enterprises. A few years
later, experiments with subsoil drainage systems were
introduced with a good result in terms of improved
drainage and reduced mosquito populations (Watson,
1929).
Port Swettenham was located further down the
Klang River, surrounded by mangrove swamps. The
harbour at Port Swettenham was constructed during
the late 1890s and, soon after the construction an
alarming number of malaria cases were registered.
Almost the entire labour force was affected and
government officials had to be hospitalised in great
numbers. Also, the ship crews were severely attacked
when the harbour became operational. Entomologi-
cal surveys later identified A. sundaicus as the most
important malaria vector in Port Swettenham.
As a means of vector control, earthen bunds were
built between the sea and the residential areas to pre-
vent the inflow of tidal water and behind the bunds
a network of surface drains was constructed. Each
drainage outlet was fitted with an iron pipe and could
be opened during low tide and closed during high tide
(Travers, 1903, 1904). This so-called tidal drainage
took advantage of the falling tide to drain the low-lying
land, which had become subject to invasion by seawa-
ter. One problem experienced along the stretch from
Klang Town to Port Swettenham was the effect of the
railway line since this obstructed the natural drainage
flow. The railway was constructed on a bund. Breed-
ing opportunities for mosquitoes were created behind
the bund, and culverts had to be constructed at reg-
ular intervals along the railway bund to reduce pool-
ing (Watson, 1905). Vegetation clearance, small-scale
landscaping and the application of crude kerosene oil
to suspected breeding sites were also carried out along
with the major drainage activities. Similarly, in both
Klang and Port Swettenham the environmental inter-
ventions were supportedby the treatmentof cases with
quinine. The interventions were the result of detailed
planning and cost estimates, and included contribu-
tions from a diverse set of actors including the Govern-
ment Railway Engineers, Harbour Master, District Of-
ficer and District Surgeon. The results of the interven-
tions in both Klang Town and Port Swettenham were
very impressive and well documented with dramatic
reductions in the number of malaria cases (Travers,
1903, 1906) and 2–3 years after the work was initi-
ated both towns were substantially free of indigenous
transmission (Bradley, 1994).
It can well be argued that the early success achieved
by Watson at Klang was for a great part the result of
luck and a trial and error approach since the detailed
local malaria vector ecology was not worked out at
the time. It was not until Watson initiated mosquito
control in the rubber estates in the hill areas around
Klang that the complexity of vector ecology and con-
trol became clear. On these estates clearing jungle and
large-scale surface drainage, that had been so success-
ful in the lowland areas, only increased the malaria
problem. Others had experienced the same problems
when clearing vegetation in the hilly residential ar-
eas of Kuala Lumpur. Watson found that the breeding
habitats of the highland vector, A. maculatus, were
very different from those of the lowland vector, A.
umbrosus. Anopheles maculatus favoured breeding at
the edges of the flowing water of ravine streams that
were exposed to sunlight. Clearing of jungle and mak-
ing the water flow in a drain cut down the middle of
natural waterways created ideal conditions for the hill
vector. The combined experiences of Watson at differ-
ent locations close to Klang resulted in the develop-
ment of different strategies for vector control depend-
ing on local ecology and vector preferences. In the
low-lyingareas on the coastal plains where settlements
were close to areas of dense jungle swamps intermixed
with patches of cultivated land, permanent sub-surface
drainage or drainage systems that allowed for contin-
uous drainage of water from swamps and residential
104 F. Konradsen et al. / Acta Tropica 89 (2004) 99–108
areas combined with clearing of vegetation had a great
effect on A. umbrosus. In areas where the mangrove
had been cleared and the tidal water mixed with collec-
tions of fresh water on land A. sundaicus bred in great
numbers in the brackish pools. In this situation, as at
Port Swettenham, building earthen bunds, land level-
ling or constructing drainage systems along the coast
and installing tidal gates to remove salt water had a
great effect on reducing breeding of A. sundaicus.In
the hill areas there were multiple sun-exposed streams
often as a consequence of vegetation removal to fa-
cilitate the establishment of estates. In these areas the
malaria vector A. maculatus could be controlled by
placing closed pipes in the streams or other forms of
sub-surface drainage to remove breeding sites (Singh
and Tham, 1988). Later, it was found cost-effective
to control A. maculatus breeding by completely shad-
ing streams or covering them with coconut husks.
Also, stream flushing devices were installed in hillside
streams making it possible to generate weekly releases
of water for flushing purposes. It later became appar-
ent that different potential vector habitats of Malaysia
required different land and water management inter-
ventions depending on the specific preferences of the
vector.
The experience with drainage for vector control
at Klang was later introduced and further advanced
in many parts of Malaysia, Singapore and else-
where in Asia (Watson and Hunter, 1921; Scharff,
1935; Tweedie, 1940). Also, the experiences from
Malaysia provided important inputs into the design of
malaria-vector-control activities in rural USA, and the
exchange of experiences between the research station
at Klang and the Rockefeller Foundation facilitated
this transfer of knowledge from Malaysia to the USA
(Watson, 1929). However, one of the wider ranging
implications of the work at Klang and Port Swet-
tenham was the empirical evidence and the general
experiences leading to the formulation of the concept
of species sanitation: the selective modification of the
environment to render a particular anopheline of no
importance as a vector in a particular setting (Bradley,
1994). The principles behind species sanitation had
already emerged from the early work of Ross in India
(Ross, 1899) but it took the experiences in Malaysia
and not least the field work and theoretical work of
Swellengrebel in Indonesia to conceptualise the idea
of species sanitation (Bradley, 1994).
3.3. Managing stream water flows for the prevention
of malaria: vector breeding in Sri Lanka
In Sri Lanka (Ceylon, from the beginning of the
British period until 1972), the importance of rivers
and streams in generating large numbers of the most
important vector of malaria has been well documented
and the relation between river water flowand mosquito
breeding was known early in the 20th century (Carter
and Jacocks, 1929, Chellappah, 1939).
In 1938, a range of experiments was initiated to re-
duce the breeding of vectors that occurred, especially
outside the rainy season or during periods of drought
when pools would form in large numbers in the stream
and riverbeds. A number of engineers from the medi-
cal and sanitary services designed a range of different
types of siphons and small dams in an attempt to flush
a stretch of river to eliminate the breeding of mosquito
larvae (Worth and Subrahmanyam, 1940). The ratio-
nale behind the control intervention was the removal
of mosquito larvae from their natural breeding sites by
the creation of strong currents and the final stranding
of the larvae when the water level falls. Flushing of
streams also inhibited plant growth, thereby reducing
opportunities for larval breeding (Singh and Tham,
1988). More than 30 installations were placed to reg-
ulate flows in five different river systems in Sri Lanka.
The dams constructed across the rivers were 6 to 21 m
wide, making volumes between 500 and 2500m
3
available for flushing. The peak discharges during a
“flush” from the siphons ranged from 0.3 to 0.6m
3
/s,
generating a water-flow velocity of 0.2–0.5m/s. The
engineers working in Sri Lanka were inspired by the
positive results from Malaysia with the anti-larval
flushing of waterways and adopted a modified version
of the automatic siphons used in Malaysia (Nicholas,
1939). Most of the experiments focused on the tech-
nical and operational feasibility of installing siphons
in Sri Lanka but aspects of cost were also discussed
for the various types of dams and siphons tested. Less
emphasis was placed on the assessment of the effec-
tiveness of the interventions on the actual breeding of
mosquitoes and possible implications for the transmis-
sion of malaria. The main findings from the 2 years’
of experimentation with operating siphons were that
their effectiveness depended very much on the local
stream conditions and the conditions of the banks. The
amount of silt and floating vegetation carried by the
F. Konradsen et al. / Acta Tropica 89 (2004) 99–108 105
river also determined the efforts required for mainte-
nance of the structures and the effectiveness of flush-
ing devices was reduced substantially during periods
of very low river flow. However, the early experiments
with siphons in Sri Lanka identified avenues for further
testing and hand-operated siphons were seen as more
promising than the fully automatic designs despite the
higher manpower investment in operations. Following
the work in Sri Lanka, experiments were continued
in India and elsewhere in Asia. Recently, different
options for the management of water levels in streams
in Sri Lanka have been discussed and the linkages
between stream water flows, breeding and malaria
transmission documented (Konradsen et al., 1998;
Amerasinghe et al., 1999; Van der Hoek et al., 2003).
Experiments are currently under way to further assess
the possibilities of regulating water flows and reduce
the degree of pooling in waterways as a means of
controlling the breeding of malaria vectors. One such
experiment taking place in the North Central Province
of Sri Lanka along an eight kilometres stretch of
river associated with outbreaks of malaria have sig-
nificantly reduced the breeding potential of the main
vector species in the area. This was achieved through
close collaboration with the irrigation department and
the health authorities and the involvement of the local
communities. The results were achieved by removing
trees blocking the stream, cutting hanging branches
and by flattening the streambed and straightening
curves (Boelee et al., 2003). However, the replica-
bility, cost-effectiveness and sustainability of such
interventions still need further documentation.
4. Discussion
The review of literature from the first half of the
20th century shows an impressive ingenuity in ex-
perimenting with malaria-vector control. These activ-
ities were a concerted effort by medically qualified
staff, entomologists, engineers and public administra-
tors across many different departments, such as agri-
culture, health, transport, urban planning and the army.
Some disagreement between the engineering side fo-
cusing on preventive measures and the curative med-
ical trained professionals over resource prioritisation
and control strategies does come through in a few of
the documents from the 20th century. However, the
interdepartmental and interdisciplinary collaboration
was crucial for the success of environmentally-based
malaria-control interventions and a feature too often
lacking in the activities implemented today. Clearly,
the involvement of the local communities in malaria
control during the early 20th century was quite differ-
ent from the approaches followed by many of the gov-
ernment agencies and NGOs of today. The approaches
followed earlier were clearly top-down and based on
strict incentive and disincentive systems with heavy
structures to support enforcement. The different out-
come of the overall control efforts at Mian Mir and
Klang may also, to some extent, be a reflection of
the different ways the two operations evolved from
site identification, selection of interventions and lo-
cal involvement. The case of Mian Mir was initially
selected and guided by outside scientists, supervising
large numbers of “coolies” and dealing with an army
contingency. In the case of Klang, the local stakehold-
ers were playing a much greater role because they fi-
nanced the implementation and provided input to the
design of interventions. At Mian Mir the focus was
on labour intensive mosquito habitat sanitation as op-
posed to the more permanent, but capital intensive,
habitat modifications at Klang.
The three cases discussed in this review clearly
point towards the site-specific nature of the land and
water management interventions that can be expected
to yield positive results. Without detailed knowledge
of the ecology of the local vector and the epidemiol-
ogy of the disease any intervention will be a shot in
the dark or may potentially do more harm than good.
In 1979, the WHO Expert Committee on Vec-
tor Biology and Control classified environmental-
management for vector control as environmental
modifications, environmental manipulations, and
modification or manipulation of human habitation
or behaviour (WHO, 1980). The classification cov-
ers the land- and water-management activities or
general-engineering-based interventions tested early
in the 20th century. However, one of the definitions
that WHO provided in 1979 makes it clear that the
modifications made to control the disease vectors
must not have “adverse effects on the quality of hu-
man environment”. This may rule out quite a few of
the interventions practiced earlier because many of
the permanent modifications of the environment re-
sulted in massive destruction of what today would be
106 F. Konradsen et al. / Acta Tropica 89 (2004) 99–108
categorized as valuable ecosystems, such as wetlands,
freshwater streams or mangrove swamps. However,
as with most of the development activities during the
greater part of the 20th century, the implications for
the natural environment were never given much atten-
tion. Similarly, some of the interventions resulted in
the forced relocation of population groups and may
not have been in compliance with the social standards
of today.
What is very striking in the literature from the
early 20th century is the emphasis on the costing of
interventions and, to some extent, also the compar-
ison of interventions based on simple cost-effective
measures. Similarly, the direct cost of malaria to gov-
ernment departments or the wider economic cost of
the malaria burden to production systems or society
features prominently in the literature. The need for
better estimates of the economic cost of disease to
communities and governments has also received in-
creasing attention over the past years. Clearly, the
priorities during the early 20th century and the selec-
tion of indicators of the economic cost of the disease
were a reflection of the political systems in place and
not necessarily the priorities of the local communities.
However, the very detailed estimations of cost for
the different engineering and environment-based
vector-control programs provide a valuable input even
today for the identification of various cost compo-
nents, and the resources needed for implementation,
making it possible to discuss the likelihoodof financial
viability. For example, it is likely that the significant
labour inputs required by many of the interventions
pursued during the early and mid-20th century would
have to be replaced by increased mechanization to be
cost-effective today.
Many of the environmental interventions could be
designed to have additional economic benefits over
and above disease reduction as the experimentation
with alternate wet and dry irrigation in rice cultivation
(Van der Hoek et al., 2001) and the secondary benefit
of drainage activities resulting from land reclamation
or increased agricultural productivity (Harmancioglu
et al., 2001) have shown. The focus on secondary ben-
efits and the clear link with financial and economic
implications of the disease on the productive sectors
was a key factor behind the successes in Malaysia.
Most of the successful control programs im-
plemented during the peak of the environmental-
management for the vector control era were under-
taken along with large-scale use of chemotherapy or
oil-based anti-larval products. This makes it difficult
to isolate the contribution made by engineering-type
interventions to overall disease control, while the ef-
fect on vector abundance was easier to quantify. Even
today, environmental vector-control options would
always be combined with a strategy for the early
detection and treatment of malaria cases.
Of the many different interventions discussed,
drainage is clearly one of the oldest and best doc-
umented methods of environmental vector control
and has been implemented as surface, subsurface or
vertical drainage systems. Nichols (1907) published
a detailed account of the early malaria control activ-
ities undertaken in the West Indies, emphasizing the
drainage interventions supervised by army engineers.
Scharff (1935), Craig (1937) and Singh and Tham
(1988) published detailed technical accounts of the
different options for vector control through drainage,
drawing heavily on the experiences from Malaysia
and Singapore. These various options were described
in the context of different vector habitats. LePrince
(1920) argued strongly for the use of permanent
drainage and the involvement of health officials when
planning the development of townships in the USA.
The large-scale labour intensive projects implemented
by New Deal agencies in the USA during the 1930s
have been highlighted for their efforts in combating
malaria, primarily through the drainage of mosquito
producing wetlands. However, Humphreys (1998),
in a large review of evidence seriously questions the
impact of these projects on malaria transmission and
doubts if these projects should be seen as a model for
the developing countries today facing severe problems
of malaria.
Different stream and river-water-management inter-
ventions and strategies have been tried out to reduce
vector breeding. In the 1930s, in the Philippines, Rus-
sell was able to control the local vector by constructing
sluice gates that were used to regulate water levels and
whereby the emptying of an upper section of a stream
resulted in the flushing of the section below. These and
other experiments were discussed in a key publication
by Williamson and Scharff (1936) where the differ-
ent approaches relating to “sluicing” and “flushing”
of streams were reviewed. Automatic siphons that
were constructed in Penang, Malaysia before World
F. Konradsen et al. / Acta Tropica 89 (2004) 99–108 107
War II were in good operating condition, functioning
as intended in 1992 according to Jobin (1999). The
recent experiences from Sri Lanka not only included
options related to flushing but also a more general
discussion on how to create a water level, above pool-
ing level, using existing irrigation-related infrastruc-
ture (Konradsen et al., 1998; Matsuno et al., 1999).
Clearly, a wealth of knowledge and innovations is
available from the experiences generated during the
early 20th century. To make the best use of the ex-
periences a renewed interest is needed in engineering
methods for vector control. The site-specific nature
of the types of interventions discussed will require a
strong local research capacity to support field-testing.
One step in this process of revitalizing the research
efforts has been the identification of documents in
the process of establishing the research agenda for
the Systemwide Initiative on Malaria and Agriculture
(SIMA). These documents, along with the reviews
published in the past (Takken et al., 1990; Rafatjah,
1988; Onori et al., 1993; IRRI, 1988), will be an im-
portant starting point for future experiments. Efforts
to reduce the global burden of malaria need the input
from professionals in the area of land and water man-
agement.
Acknowledgements
We are grateful for the support provided by Mr.
Martin Larsen in the search for old references and
his efforts to obtain copies of papers from around the
world. We highly appreciate the support services pro-
vided by Ms. Mala Ranawake in writing this paper.
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- Using historical records to supplement the modern health records has a number of advantages in addition to extending the record length. While local drainage and land use management schemes have been used for global vector control since the 1900s (Kitron and Spielman, 1989; Konradsen et al., 2004; Walker and Lynch, 2007), the record prior to the late 1950s is unaffected by mass interventions with dichlorodiphenyltrichloroethane (DDT). Moreover, while mass population movements have always occurred, general population mobility was far below today's unprecedented levels Tatem et al. (2012).
[Show abstract] [Hide abstract] ABSTRACT: Malaria case statistics were analysed for the period 1912 to 1960 to identify inter-annual variations in malaria cases for the Uganda Protectorate. The analysis shows the early to mid 1930s to be a period of increased reported cases. After the data gap coinciding with WWII, malaria cases trend down to a relative minimum in the early 1950s, before increasing rapidly after 1953 to the end of the decade. Data for the Western Province confirm these national trends, which at the time were attributed to a wide range of causes, including land development and management schemes, population mobility, interventions and misdiagnosis. Climate was occasionally proposed as a contributor to enhanced case numbers, and unusual precipitation patterns were held responsible; temperature was rarely if ever considered. In this study a dynamical malaria model was driven with available precipitation and temperature data from the period for five stations located across a range of environments in Uganda. In line with the historical data, the simulations produced relatively enhanced transmission in the 1930s, although there is considerable variability between locations. In all locations, malaria transmission was low in the late 1940s and early 1950s, steeply increasing after 1954. The results suggest that the impact of multiannual variability in temperature, while only on the order of 0.5 degrees C, was su�fficient to drive some of the trends observed in the statistics, and thus the role of climate was likely underestimated in the contemporary reports. As the elimination campaigns of the 1960s were superimposed on a previous, partly climate driven increase in malaria, this emphasizes the need to account for climate when planning and evaluating intervention strategies.- Larvae-targeting strategies, on the other hand, are less susceptible to such problems because of the limited mobility of larvae. Larval source reduction, while less commonly selected in current malaria control programs, has been applied to seasonal pools (e.g., larviciding to kill larvae), river channels (e.g., stream-flow manipulation to flush larvae), and irrigation fields (e.g., intermittent irrigation to interrupt larval development by occasionally drying breeding sites) [5,[27][28][29][30]. Around dam-related reservoirs, water-level manipulation could be used, where the reservoir water levels are controlled to create unfavorable breeding conditions for larvae.
[Show abstract] [Hide abstract] ABSTRACT: Background One of the concerns for future malaria epidemiology is the elevated risks of malaria around an ever-increasing number of dam sites. Controlling larval populations around reservoirs behind dams by manipulating the water levels of reservoirs could be an effective and sustainable measure for suppressing malaria epidemics; however, the effectiveness of the water-level manipulation and the contributing mechanisms have been poorly studied. In this paper, we focus on how water recession may lead to larval stranding.Methods Larvae of An. albimanus were studied to assess their susceptibility to stranding under different conditions representing reservoir shoreline environments in an experimental tank (50 cm¿×¿100 cm). The tank was initially seeded with 80 larvae uniformly, and the numbers of larvae stranded on land and remaining in water were counted (summed up to recovered larvae), following the recession of water. The vertical water drawdown rate and the proportion of stranded larvae to recovered larvae (p) were measured. Shoreline conditions tested were inclinations of shore slopes (2% and 4%) and surface types (smooth, vegetated, rough, ridged).ResultsFor the 2% slopes, the proportions of stranded larvae (p) increased by about 0.002, 0.004, and 0.010 as the water drawdown rate increased by a centimeter per day on the smooth, rough, and vegetated surfaces, respectively. p for the 4% slopes were smaller than for the 2% slopes. Unlike other surface conditions, no significant correlation between p and the drawdown rate was observed on the ridged surface.Conclusions Larger proportions of Anopheles larvae were stranded at higher water drawdown rates, on smaller reservoir slopes, and under rough or vegetated surface conditions. Three mechanisms of larval stranding were identified: falling behind shoreline recession; entrapment in small closed water bodies; and inhabitation in shallow areas. Depending on the local vectors of Anopheles mosquitoes, the conditions for their favorable breeding sites correspond to the conditions for large larval stranding. If these conditions are met, water-level manipulation could be an effective measure to control malaria along shorelines of reservoirs behind dams.- For hundreds of years malarial disease was known to be linked with swamps, and control efforts mainly consisted of drainage interventions for sanitation purposes (Gilles and Warrell, 1993). After the key discoveries of the causative agents of malaria and its vectors at the end of the 19th century (Cox, 2010 ), more specific control tactics were developed through management of the environment (Konradsen et al., 2004). In addition, the discovery of the efficient and affordable curative drug chloroquine considerably reduced malarial morbidity and mortality for decades (Wellems, 2002; Krafts et al., 2012).
[Show abstract] [Hide abstract] ABSTRACT: The intolerable burden of malaria, when faced with high levels of drug resistance, increasing insecticide resistance and meagre resources at the national level, remains a great public health challenge to governments and the research/control community. Efficient control methods against the vectors of malaria are desperately needed. Control strategies for malaria that integrate the transfer of sterile sperm by released males to wild virgin females with other control tactics are currently being developed, and optimised mass-rearing, irradiation and release techniques are being validated in several field sites. However, the success of this strategy as part of wider pest control or health management programmes strongly depends on gaining public understanding and acceptance. Here we attempt to review what progress has been made and the remaining challenges surrounding the use of the sterile insect technique against malaria from technical and social perspectives.- As with most of the development activities during the 20 th century, the implications for the natural environment were not given much attention. Similarly, some of the interventions that resulted in the forced relocations of population groups may not be acceptable by current social standards (Konradsen et al, 2004). Emergency relocation of refugees from endemic areas could provide a large reservoir of infection and, if aircraft, trains and/or buses are used, will increase the possibility of introducing exotic vectors into 2004).
[Show abstract] [Hide abstract] ABSTRACT: Malaria transmission in the Greater Mekong Subregion depends on, among other factors, vector behavior and ecology, and the degree of contact between humans and the Anopheles mosquitoes. This chapter will review and update knowledge presented in the 2003 Mekong Malaria monograph for planning and implementing evidence-based vector control programs. Collation of 150 publications and reports showed that the highest number of vector species reported included An. minimus Theobald complex (26.74%), An. dirus Peyton and Harrison (14.26%), An. sundaicus (Rodenwaldt) (5.65%), An. sinensis Wiedemann (4.29%), An. maculatus Theobald (4.23%), An. philippinensis Ludlow (1.62%), An. annularis Van der Wulp (0.37%), An. campestris Reid (0.25%), and An. lesteri Baisas and Hu (=anthropophagus) (0.045%). Other Anopheles species accounted for 44.44%. Anopheles dirus was incriminated as a vector of Plasmodium knowlesi malaria in Viet Nam for the first time, but remained a suspected simian vector in other countries in the region. Well-designed trials of innovative strategies in intractable and difficult situations are needed, including a better understanding of the various causal relations and interactions between physiology, environment, and vector bionomics. While current front-line vector control interventions have contributed significantly to a worldwide decrease of malaria, indoor residual spraying and insecticide-treated bednets/ long lasting insecticidal bednets have had variable impact on exophilic/exophagic and/or early biting vectors. As vectors' responses to control measures vary in different areas, entomological studies on the efficacy of insecticide-treated bednets and other innovative control tools to ensure that strategies are tailored to local circumstances. Given that current tools are insufficient to break transmission cycles, more strategic investments into research on outdoor transmission, monitoring of insecticide resistance, vector species identities, vector mapping, target profiles of new control technologies and delivery systems are required.- Drainage is the water management method for disease vector control with the longest history (Konradsen et al., 2004). As early as the 6th century BC, the Greeks and the Romans were aware of the association between fevers, swamps and stagnant waters.
- oping countries ( Seidu et al . 2008 ) . If household waste water can be seen as a desirable resource , on well - drained garden plots , then it is less likely to contribute to stagnant drains within the village and associated insect vector and disease problems and can provide an alternative to irrigation networks with formal delivery structures ( Konradsen et al . 2004 ) . It is characteristic of many homesteads that the soil of their garden plots is generally more fertile than surrounding areas ( Keatinge et al . 2001 ) and the addition of household organic wastes can help maintain this . The opportunity to productively use such wastes also can provide opportunities for sanitation professionals to ad
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