Schistosomiasis
Control in Kwabeng
Social, Environmental, and Engineering Challenges
to Reducing Schistosomiasis Incidence
in a Rural Town in Eastern Ghana
Tufts University Department of Civil and Environmental Engineering
Project Team

Student Members:
– Casey Caldwell, Robert Curry, Charline
Han, Daron Kurkjian, Kelly Sanborn, and
Katie Shuman

Faculty Advisors:
– John Durant and David Gute
Tufts University, Dept. of Civil &
Environmental Engineering
2
The Problem

Schistosomiasis is water-borne parasitic disease that
is contracted by coming into contact with
contaminated water

We hypothesized
that hydraulic
alterations to the
river in Kwabeng
have increased the
incidence of
schistosomiasis
Source: Rob Curry
Tufts University, Dept. of Civil &
Environmental Engineering
3
Life Cycle of Schistosomiasis
Source: http://www.payer.de/entwicklung/entw2039.gif
Tufts University, Dept. of Civil &
Environmental Engineering
4
Long Term Project Objective
Decrease, if not eliminate, the incidence
of schistosomiasis in Kwabeng, Ghana
 Promote better management of water
resources in Kwabeng
 Assess the transportability of our
approach to other affected communities

Tufts University, Dept. of Civil &
Environmental Engineering
5
First Year Project Objectives
Research the nature and complexity of
the problem
 Establish baseline data for Kwabeng
 Create relationships with community
members
 Design a matrix to determine the best
possible solutions

Tufts University, Dept. of Civil &
Environmental Engineering
6
Research Methods in Kwabeng

Gathered water data
– Velocity,
Temperature, pH,
Dissolved Oxygen,
Specific Conductivity
Average
Max
Min
SpC
(mJ/cm)
0.118
0.124
0.097
pH
7.20
7.80
6.86
Temp
(oC)
DO
(mg/L)
Source: Rob Curry
25.59
29.58
24.15
7.33
7.85
6.29
Tufts University, Dept. of Civil &
Environmental Engineering
7
Research Methods in Kwabeng

Identified presence of schistosomiasis
in water and in children
– Collected snails
– Identified schistosomes in snails
– Conducted school surveys to determine
incidence of infection in children, along
with river use habits
Tufts University, Dept. of Civil &
Environmental Engineering
8
Snail and Velocity Correlation
25
Number of snails
20
15
10
5
0
0
0.1
0.2
0.3
0.4
0.5
0.6
Velocity (meters/second)
Tufts University, Dept. of Civil &
Environmental Engineering
9
Research Methods in Kwabeng

Met with community
members and leaders
– Gathered community
acceptance and
historical data for the
town

Helped establish a
committee to
continue project
efforts in Kwabeng
Source: Katie Shuman
Tufts University, Dept. of Civil &
Environmental Engineering
10
Research Methods in Kwabeng

Made maps of the before and after mining
company changes
 Used a GPS unit, measuring tape, and
compass
 Digitized the maps for use in GIS
Tufts University, Dept. of Civil &
Environmental Engineering
11
Tufts University, Dept. of Civil &
Environmental Engineering
12
Tufts University, Dept. of Civil &
Environmental Engineering
13
Tufts University, Dept. of Civil &
Environmental Engineering
14
Tufts University, Dept. of Civil &
Environmental Engineering
15
Identifying Interventions

Identified three types of interventions
– Reduce number of snails in the river
– Prevent people from exposure to parasites
– Reduce the population of parasites in
snails
Tufts University, Dept. of Civil &
Environmental Engineering
16
Selection Criteria

Cost
– Relative cost taking into account capital cost and
O&M

Feasibility
– How possible the intervention technology is in
Kwabeng
• Access to equipment
• Human health and safety concerns

Community Acceptance
– How well the proposed solution resonates with the
community
• Cultural, political and economic implications
Tufts University, Dept. of Civil &
Environmental Engineering
17
Selection Criteria Continued

Efficacy
– Success rate in decreasing the incidence
of schistosomiasis
• Can the intervention stand alone
• Has it been successful in other areas

Sustainability
– Longevity of the intervention
Tufts University, Dept. of Civil &
Environmental Engineering
18
Tufts University, Dept. of Civil &
Environmental Engineering
19
Numbering System

Cost:
• 1 = most expensive

Feasibility:
• 1 = least feasible

5 = very supported
Efficacy:
• 1 = not effective
at decreasing infection

5 = most feasible
Community Acceptance:
• 1 = not supported

5 = least expensive
5 = very effective
Sustainability:
• 1 = not sustainable
5 = indefinitely sustainable
Tufts University, Dept. of Civil &
Environmental Engineering
20
All Possible Rated Interventions
Specific Intervention
Increase staff school visits
Free schisto screening & drugs
Public Latrines
Town-wide education campaign
Do nothing
Increase Predators
Increase Direct Snail Competitors
Plants- for Shade
Plants-in Water
Increase slope of channel
Reduce Cross-sectional area
Restoring Flow or Modified Flow
Herbicide
Mollusicide
Public showers
Wells
Public Taps
Recreation Area
Expand Household Distribution System
Cost
UW 10%
3
0.3
2
0.2
3
0.3
5
0.5
5
0.5
4
0.4
4
0.4
5
0.5
3
0.3
1
0.1
1
0.1
1
0.1
3
0.3
3
0.3
2
0.2
3
0.3
3
0.3
3
0.3
2
0.2
Feasibility Community Acceptance Efficacy
UW 15%
UW
15%
UW 35%
4
0.6
3
0.45
3 1.05
2
0.3
4
0.6
4
1.4
5
0.75
2
0.3
4
1.4
3
0.45
4
0.6
3 1.05
5
0.75
1
0.15
1 0.35
2
0.3
3
0.45
1 0.35
2
0.3
3
0.45
1 0.35
3
0.45
3
0.45
3 1.05
4
0.6
3
0.45
3 1.05
1
0.15
2
0.3
4
1.4
1
0.15
2
0.3
4
1.4
4
0.6
4
0.6
5 1.75
2
0.3
1
0.15
3 1.05
2
0.3
1
0.15
2
0.7
3
0.45
3
0.45
2
0.7
4
0.6
2
0.3
2
0.7
4
0.6
4
0.6
2
0.7
4
0.6
3
0.45
1 0.35
4
0.6
4
0.6
2
0.7
Tufts University, Dept. of Civil &
Environmental Engineering
Sustainability Total Rating
UW
25%
(Max:5)
3
0.75
3.15
3
0.75
3.25
1
0.25
3.00
3
0.75
3.35
1
0.25
2.00
1
0.25
1.75
2
0.5
2.00
3
0.75
3.20
2
0.5
2.90
5
1.25
3.20
4
1
2.95
5
1.25
4.30
2
0.5
2.30
2
0.5
1.95
3
0.75
2.55
3
0.75
2.65
3
0.75
2.95
4
1
2.70
4
1
3.10
21
Snail Control: Reducing the amount of snails in the river
Type of
Intervention
Specific
Intervention
Increase
Predators
Cost
- Purchase
cost
Monitoring
4
Increase
Direct Snail
Competitors
-Purchase
cost
-Monitoring
4
Biological
Controls
Plants- for
Shade
-Purchase
cost
-Monitoring
5
-Labor
Plants-in
Water
3
Sustainability
- Talapia already
present in the water,
problem persists
1
-Acuta already present,
Bulinus still present
-Rebalancing effect of
nature, would force
restocking of
competitors
2
-Depends on
community education
that trees need to
protect river from
becoming hospitable to
plants that snails live
on
3
-Need to constantly
“weed” entire
watershed
2
Community
Acceptance
People eat snails
from the river, must
be Bulinus specific
3
Unknown, likely to
be neutral
3
High, restoration
efforts good, some
farmers close to
rivers may oppose
3
Plants are part of
river ecosystem
3
Efficacy
Feasibility
- Must teach people
Low, ecologically
to not eat the
impractical
predatory fish
1
2
Low, plant and
algal food source
would need to be
highly degraded
-Predators of
competitors would be
attracted to rivers
1
2
High, areas with
less plants had
few to no snails
-Deforestation on
banks could quickly
revert situation to
present conditions
3
3
Plants provide
part of the surface
snails live on,
-Would expose
branches and
workers to river
other submerged
-Safety issues
surfaces would
need to be
removed as well
3
Tufts University, Dept. of Civil &
Environmental Engineering
Total
Weighted
Score
1.75
2.00
3.20
2.90
4
22
Type of
Intervention
Specific
Intervention
Increase slope of
channel
Cost
Labor:
Construction:
Overhead:
Design:
Volunteered
1
Increase Velocity
– River Alteration
Reduce Crosssectional area
Labor:
Construction:
Overhead:
Design:
Volunteered
1
Increase Input
through
Restoring Original
Flow or Modified
Flow
Labor:
Construction:
Overhead:
Design:
Volunteered
1
Herbicide
-Purchase cost
-Labor to apply
3
Sustainability
Community Acceptance
High, permanent structure
- Need partnership with
mining co.
- Mining operations to
resume June 04
-Reduces recreational use of
river
-Massive earth moving work
may be opposed
High, targets
snail habitat
2
4
1
High, targets
snail habitat
- Mining co. has access
to equipment and
experience altering
rivers
-may interfere with river
uses
5
-High, permanent
structure
-May require routine
maintenance
4
-High, permanent features
-Community &
Government Vigilance in
protection of river
5
- Need to continually
reapply
2
Chemical
Controls
Mollusicide
-Purchase cost
-Labor
3
- Need to continually
reapply
2
-Reduces recreational use of
river
-may impede water
gathering
- Need partnership with
mining co.
Efficacy
2
- Need partnership with
mining co.
- Support from some
Assembly men and farmers
4
High, targets
snail habitat
4
-Very low
-Water supply would be
contaminated with
herbicides
- Mining co. has access
to equipment and
experience altering
rivers
- Construction already
done on Abudusu
-Difficult to implement
- Mining co. has access
to equipment and
experience altering the
specific rivers
-Dependent on Mining
Co. Compliance
4
-High,
depending on
dose
-Pesticide application
could negatively impact
agriculture on farms
3
2
-Neutral,
dosages
commonly
used are
ineffective to
control snail
population
1
Tufts University, Dept. of Civil &
Environmental Engineering
2
Total
Weighted
Score
3.20
2.95
1
5
1
-Low
-Adding pesticide to public
water supply
Feasibility
-Some snails are food
source, would have to
prevent contaminating
food supply
4.30
2.30
1.95
2
23
Biological Controls

Adding Terrestrial Plants for
Shade
– Shade reduces aquatic plant life in
river, habitat of the snails
– Competing land requirements from
farmers near banks of river
– Correlation between high shade and
low/no snail population

Harvesting Aquatic Plants
Source: http://www.kauai-vacationrentals.com/shadesofgreen/100shades.htm
– High labor demand
– Competing growth surfaces reduce efficacy
– Continual removal of aquatic plants will lower
biological productivity of river
– Kwabeng community view option as drastic
Tufts University, Dept. of Civil &
Environmental Engineering
24
Biological Controls

Increase Snail Predator Population
– Fishing of beneficial predators would limit snail reduction
gains
– Ecological equilibrium would require constant addition of fish
to effectively reduce snail populations
– Risk of unintended consequences of species introduction
– Population monitoring costs high

Increase Direct Snail Competitors
– Competitive species could be local foods (certain snail
species)
– Ecological equilibrium between species will require
excessive competitor population
Tufts University, Dept. of Civil &
Environmental Engineering
25
Chemical Controls

Herbicide
– Ineffective long term solution
– Risk to farmers who irrigate from river water
– Town water supply impacted

Molluscicide
– Requires 8 hour contact time with river
– Temporary solution
– If implemented incorrectly could increase chemical
resistance of snails
– Towns water supply impacted
Tufts University, Dept. of Civil &
Environmental Engineering
26
Increasing the River Velocity

Increase slope channel
–
–
–
–

Effective, but impractical
Major earth moving needed
Water supply weir would need to be removed
Changes to the water supply system drastic
Reduce Cross-Sectional Area
– Entire river would need width contraction – high expense
– Maintenance against erosion could be high, with seasonal
storm and flood events
– Community skeptical of option
Tufts University, Dept. of Civil &
Environmental Engineering
27
Increasing the River Velocity

Increase Input Through River
Restoration
– Rejoin the Awusu and the
Abodusu Rivers
– Partnership with Mining Co.
necessary
• Earth moving equipment in
hands of Mining Co.
• Experience in river alterations
– Highly effective
– Desired by many in community
Source: Charline Han
Tufts University, Dept. of Civil &
Environmental Engineering
28
Alternatives to Using the River
Specific
Intervention
Public
showers
Wells
Cost
-construction
costs
-pay attendant
-maintenance
-water costs
2
- pay attendant
-construction
with machinery
-maintenance
3
Public Taps
-expand of
water system
-pay attendant
-maintenance
-water costs
3
Recreation
Area
-construction
-maintenance
3
Expand
Household
Distribution
System
Feasibility
-would need
land
-need to have
water co. bring
in pipes
3
Community
Acceptance
- Children should
shower for free b/c
they use latrines for
free
3
-don’t know
depth to water
table
4
- People prefer to get
water from river or
taps
2
- 9 taps already
exist in town
4
-Are supplies
available in
Ghana?
- Many people use
public taps
- Children in charge
of getting water
pocket money and go
to river
4
-would children use
it?
4
3
- Ghana Water
-pay water co. to
Co Ltd. not
expand
cooperating with - Very expensive
-water costs
secondary
-maintenance(?)
school
2
3
4
Efficacy
Sustainability
Total
-Must be coupled with
other intervention
-doesn’t prevent river
use
-workmanship
and
maintenance
2.55
2
-Must be coupled with
other intervention
-doesn’t prevent river
use
3
-too much use
could effect
water table
2
3
- Must be coupled with
other intervention
-doesn’t prevent river
use
-water co.
must maintain
water system
and quality
2
-Must be coupled with
other intervention
-doesn’t prevent river
use
1
3
-workmanship
and
maintenance
-Must be coupled with
other intervention
-doesn’t prevent river
use
-water co.
must maintain
water system
and quality
2
4
Tufts University, Dept. of Civil &
Environmental Engineering
2.65
2.95
2.70
4
2.95
29
Public Showers






Construction, operation, and maintenance
costs
Adults would be willing to pay a small fee, but
children would have to be free.
Attendant needed for maintenance and up
keep.
Need cooperation with Ghana Water Ltd.
Does not prevent river use
Must be coupled with other interventions
Tufts University, Dept. of Civil &
Environmental Engineering
30
Public Wells






Construction, operation, and
maintenance costs
Don’t know depth to water table
Small fee for usage (1-2¢)
Community is resistant to using
wells because they are usually
hand dug and the water does
not come from the river
Does not prevent river use
Must be coupled with other
interventions
Source: Charline Han
Tufts University, Dept. of Civil &
Environmental Engineering
31
Tufts University, Dept. of Civil &
Environmental Engineering
32
Public Taps
Construction, operation, and
maintenance costs
 Many taps already in town
 Small fee for usage (1-2¢)
 Does not prevent river use
 Must be coupled with other interventions

Tufts University, Dept. of Civil &
Environmental Engineering
33
Recreation Area

Construction cost and constructability.
– Are supplies available in Ghana?
Will Children use it?
 Does not prevent river use
 Must be coupled with other
interventions

Tufts University, Dept. of Civil &
Environmental Engineering
34
Expand Household Distribution System
Implementation costs high as are
recurring costs
 Not everyone has a “house”
 Requires cooperation of Ghana Water
Ltd.
 Does not prevent river use
 Must be coupled with other
interventions

Tufts University, Dept. of Civil &
Environmental Engineering
35
Schistosome Control: Reducing parasite population in snails
Specific Intervention
Medical treatment – Increase
staff for existing school visit
treatment system
Cost
Salary of nurse
Feasibility
- 1 nurse has outings to schools
three times per week over entire
district for many illnesses
(including schisto)
- Cooperation of Ghana Health
Services that runs clinic
- Physical space availability at
clinic
3
Medical treatment – Monthly
free schisto screening & drug
distribution day
Diagnosis
- Salary for a team of
nurses/DRs/lab techs for 1
day
Treatment
- Praziquantel: $1.33 per
dose for adult, $0.66 per
dose for children
4
- Commitment from health
personnel
2
Reducing egg return to river
from humans – latrines
Construction
- $2-3 per day cost of
labor
- Equipment costs
- Capital costs for building
materials
O&M
- $10-12 per month
Income
- Children use for free
- $0.10 per use
2
- Access to construction
equipment
3
Children
- Cost of teacher/health
care professional’s time
Town-wide
education
campaign
Adults
5
Do nothing
- Makes people feel weak
and anemic
5
5
- 5 Primary schools - Teachers are
qualified to teach health issues
- Hard to teach very young
children
- Difficult to bring adults together
physically to educate them
- Differing levels of education and
understanding within the
community
3
Community Acceptance
- Committee supports
increased assistance at
clinic
- Accountability is a
concern
3
- Committee ID poverty as
a barrier
- Committee recognized
difficulties in accessing
drugs
- focused screening
5
- Double the rate of
screening
- Students are required
to self diagnose
symptoms
3
- People are constantly
reinfected
- One dose treatment
4
4
- Public latrines exist in
town – new set just built
- Drug problem at latrines
- Must be free for children
- Cost discourages use
- Eggs could be entering
the river if not designed
properly
- Proximity to
residences
- Cost discourages use
2
4
- District commissioner
very helpful
- Not all children go to
school
- Adults don’t prioritize
schistosomiasis
- Community resistance to
behavioral changes
4
- Invested in finding a
solution to the problem
- Feasible
Efficacy
1
Tufts University, Dept. of Civil &
Environmental Engineering
- Constant reeducation
necessary
- Comprehensive
education program
could greatly reduce
(re)infection rates
3
- Current interventions
are not very effective
1
Sustainability
- Long term funding
needed
- Follow up needed
Total
Weighted
Rating
3.15
3
- Praziquantel gives
little to no immunity
- Reduces return of eggs
to river
3.25
3
- Finite life span
3.00
1
- Constant reeducation
process as children
enter/leave school
3.35
- Constant reeducation
necessary
3
- Hypothesize that
incidence will increase
2.00
1
36
Medical Treatment-Increase Staff for Existing
School Visit Treatment System





Currently one nurse conducts school visits to
evaluate children’s health
Students are required to self-assess illnesses
Town clinic run by Ghana Health Services,
therefore requires cooperation
Community questions current system’s
accountability and supports increased
assistance
Long term monitoring needed
Tufts University, Dept. of Civil &
Environmental Engineering
37
Medical Treatment-Monthly Free
Schistosomiasis Screening and Drug
Distribution Days
Salary of nurse, MDs, and lab techs
 Cost of Praziquantel (most common
drug used for treatment)
 Reinfection rate a concern
 Medication does not confer immunity
 Reduces egg return to the river, thus
breaking life cycle

Tufts University, Dept. of Civil &
Environmental Engineering
38
Latrines - Reducing Egg Return to
River from Humans





Construction, operation, and maintenance
costs
Small income generated because adults
would pay to use latrines
Latrines already exist in town and are not
widely used because of their cost to the users
Finite life span, therefore lacks sustainability
Reduces egg return to the river, thus breaking
life cycle
Tufts University, Dept. of Civil &
Environmental Engineering
39
Town-wide Education Campaign

Two target populations: children
and adults
 Cost of educated health
personnel
 Behavioral changes are often
difficult to implement and
sustain
 Constant reeducation
necessary
 Preventing schistosomiasis is
Source: Charline Han
not presently a priority in
Kwabeng
Tufts University, Dept. of Civil &
Environmental Engineering
40
No Action Alternative
Side effect of schistosomiasis is
anemia, which makes people feel weak
and decreases worker productivity
 Community is invested in working with
us to find a solution
 Hypothesis that incidence rates on the
rise

Tufts University, Dept. of Civil &
Environmental Engineering
41
Conclusions and Recommendations

Top three interventions
1. Increase river velocity by river restoration
2. Town-wide education campaign
3. Monthly schistosomiasis screening and
treatment days

Interventions can be used in
conjunction with each other
– Lower scoring interventions can be used
to supplement main intervention
Tufts University, Dept. of Civil &
Environmental Engineering
42
Future Work

Ongoing
– Locate sources of funding
– Identify international partners
Year 2 – In depth data collection on the
recommended interventions and selection of
the best intervention
 Year 3 – Design of selected intervention
 Year 4 – Implementation
 Year 5 – Monitoring and evaluation

Tufts University, Dept. of Civil &
Environmental Engineering
43
Acknowledgements








Professors John Durant and David Gute
Kwabena Kyei-Aboagye
Dr. Kwame Boadu
Kwabeng District Superintendent of Schools
Professor Manu, University of Ghana
Provost Bharucha
Tufts University Center for Children
Department of Civil and Environmental
Engineering
Tufts University, Dept. of Civil &
Environmental Engineering
44