Cost-effective and Sustainable Vector Control Methods Will be Established to Reduce VL in India, Bangladesh and Nepal Clinical Trial
Official title:
Replacement of Insecticides to Control Visceral Leishmaniasis
Visceral leishmaniasis (VL) is a public health problem in Bangladesh, India and Nepal. To
control the disease in these three countries a National kala-azar elimination program is
ongoing. One of the major pillars of the elimination program is VL vector control. Currently
there is a no public VL vector control program in Bangladesh. In India the program is
depending on Indoor Residual Spraying with insecticides. IRS with DDT and in Nepal on
Alpha-cypermethrin. The sand fly, vector of VL is already resistant to DDT and hurdles
related with IRS i.e. funds, logistics and human resources make IRS unsustainable VL vector
control method in Nepal. Thus alternative to IRS for VL vector control is highly desirable
for the success of national kala-azar elimination program in these three countries.
Through current research activities we will compare the effectiveness of three effective VL
vector control methods. They are 1) Plastering of household walls with lime (a traditional
method known in the study areas),treatment of possible sand-fly breeding places with lime and
bleaching powder; 2) Installing durable wall lining containing deltamethrin in the main
living room(s) of households; 3) Impregnation of existing bed-nets with slow release
insecticide tablet containing deltamethrin.
The study finding will be important for the national elimination program of the three
countries through discovering the most effective VL vector control method.
Visceral leishamniasis (VL; known as kala-azar in the Indian Sub-continent) is a deadly
parasitic disease if left untreated. The disease is reported from 109 districts
(Bangladesh-45, India-52 and Nepal-12). VL elimination programme was launched in 2005 between
the three countries with the set target to reduce the cases one in 10,000 populations. Toward
this set target, vector control will play a significant role. Based on the experiences in the
past during malaria eradication period Indoor residual spraying (IRS) with insecticides is
taken as the main pillar of VL vector control. Operation like IRS is expensive,
labour-intensive, require sustainable infrastructures, supplies of insecticide, spraying
equipment, trained personnel and funding over a long-term of period. These doubts about the
sustainability of IRS in poor resource settings like Bangladesh. Thus alternative of IRS
other vector control tool is highly desired. Current research activities will explore for the
alternatives of IRS (here defined as "insecticide"). The proposed three different types of
alternative of IRS are: 1) Plastering of household walls with lime (a traditional method
known in the study areas), treatment of possible sand-fly breeding places with lime and
bleaching powder; 2) Installing durable wall lining containing deltamethrin in the main
living room(s) of households; 3) Impregnation of existing bed-nets with slow release
insecticide tablet containing deltamethrin.
The study will include three different types of intervention arm and one control arm; Arm: 1)
Indoor house walls and floors will be plastered with lime (a traditional method known in the
study areas) including treatment of outdoor breeding places with lime and bleaching powder to
inhibit sand fly breeding. Arm: 2) Installing of durable wall lining containing deltamethrin
to kill immature stage of sand flies. Arm: 3) Impregnation of existing bed-nets with slow
release insecticide, deltamethrin and 4) Control group, no intervention. VL endemic areas
with 1200 households will be selected and identified 24 clusters based on geographic
characteristics. Minimum distance between each cluster will be about 50 meters. Each cluster
will have 50 households (HHs) where the different interventions will be applied. Five HHs
will be selected randomly from each cluster to measure the intervention effect on sandfly
density on 2 consecutive nights using CDC light traps at 4, 12, 24 and 52 weeks after
intervention. Baseline sand fly densities will be measured at 2 weeks before introducing the
intervention. Based on base line sandfly data the clusters will be ranked as high, moderate
and low and from them equal number of clusters will be assigned for each intervention arm as
well as control arm. Control HHs will receive commercial insecticide treated bed-nets after
the study is over. This study will be a multi-centre cluster randomized trial with three
vector control methods and will be carried out in ICDDR,B, Bangladesh, RMRI, India and in
BPKIHS, Dahran, Nepal simultaneously during a 12 months period. A total of 3600 households in
the three countries (Bangladesh-1200, India-1200 and Nepal-1200 HHs) will be included in the
study.
The cost of interventions will be assessed applying a combination of bottom-up and top-down
costing approach from the provider's perspective only. Costs attributable to effectiveness of
the interventions (i.e. reduction of sandfly density by intervention) will be calculated
separately for comparison among three types of intervention. Firstly; all inputs to be
mobilized for implementing each of the intervention will be identified, quantified and valued
in local currency separately. Based on the relationship of the inputs to outputs, costs will
be broadly classified into fixed cost and variable cost. Standard procedure will be followed
for annualization of capital costs using replacement cost, useful lifetime, discounting rate
and corresponding annualization factor taken from the standard table.
Shadow pricing will be considered for inputs to be donated for the study purpose by partner
agencies. Allocation factors (e.g. % time spent by staff, % used etc) will be applied to
apportion joint costs. Summing-up the fixed and variable costs over all total cost of each
intervention will be calculated separately. Average or unit cost will be calculated dividing
total cost of each intervention by the corresponding number of households that received the
intervention. Finally relationship between cost and effectiveness of corresponding
intervention(s) will be represented by cost and effectiveness ratio for comparison.
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