A clinical study on the measures taken in the management and control of Schistosomiasis as a public health problem in Zimbabwe since 1984.Schistosomiasis remains the second most important parasitic disease in Zimbabwe. In terms of its combined morbidity and prevalence, schistosomiasis is thought to be the most important helminth infection of man.
Since 1984, a number of control programmes have commenced around the country and a national control programme aimed at reducing morbidity is being implemented. The strategy adopted in Zimbabwe is a community based approach integrated in the primary health care syste

Chandiwana, S.K.

Makura, O.

Ndhlovu, P.

Central African Journal of Medicine

English

IDS OpenDocs

The
Central African 
Journal 
of
Medicine
Supplementary Issue to 1992 Volume 38,
1991 University of Zimbabwe Annual Research Day
CENTRAL AFRICAN
JOURNAL OF MEDICINE
Vol. 38,No. 8,1992
THE CENTRAL AFRICAN 
JOURNAL OF MEDICINE
ORIGINAL ARTICLES
Progress in the control of 
Schistosomiasis in 
Zimbabwe since 1984
P NDHLOVU, SK CHANDIWANA, O MAKURA 
SUMMARY
Schistosomiasis remains the second most important 
parasitic disease in Zimbabwe. In terms of its 
combined morbidity and prevalence, schistosomiasis 
is thought to be the most important helminth infection 
of man.
Since 1984, a number of control programmes have 
commenced around the country and a national 
control programme aimed at reducing morbidity is 
being im plem ented. The strategy adopted in 
Zimbabwe is a community based approach integrated 
in the primary health care system.
INTRODUCTION
Surveys carried out at health facilities in Zimbabwe, 
show that schistosomiasis is one of the top ten causes 
of attendance at health facilities, especially in 
children, (Secretary for Health 1991). As the disease 
is a chronic insidious problem which causes 
morbidity, its effects have not been fully recognised. 
The infection is associated with poor nutrition and 
work performance in children, and pathological 
changes in the liver, bladder and kidneys.14
Blair Research Institute 
P.O.Box 8105 
Causeway 
Harare
Blair Research Institute (BLR), the research 
department of the Ministry of Health, has much 
experience in the epidemiology and control of 
schistosomiasis. With the information available, it 
should be easier to define priority areas for 
schistosomiasis control.
For example, transmission of the disease is known 
to be seasonal and focal in space and tim e4’16 There 
is a lot of variation in the distribution of infection and 
in individual predisposition to infection. Prevalence 
and intensity of infection peaks in children and young 
adults. In addition there is a positive correlation 
between infection status in a population sub-group 
and the relative transmission potential o f water 
contact sites used2 and also a pronounced specificity 
and marked conservatism in the human water contact 
pattern'4
The main aim of the present paper is to review the 
various control projects that have been set up in 
Zimbabwe since 1984. Initially the results of the 
nationwide survey which was reported by Taylor and 
Makura18 are discussed. The survey concentrated on 
Schistosoma haematobium 'dndSchistosoma mansoni 
which are the two schistosome species affecting man 
in Zimbabwe. Since 1939, a number of surveys and 
control projects were conducted by BRI. The results 
and recommendations of these projects can now be 
implemented in the national schistosomiasis control 
programme.
MATERIALS AND METHODS
The distribution of schistosomiasis in Zimbabwe:
Fourteen thousand six hundred and fourteen school 
children, from 157 schools around Zimbabwe, were 
examined for schistosomiasis infection. From the 
results obtained, the country was divided into three 
sections (A-C) according to the prevalence of urinary 
schistomiasis (Figure I) and two sections (D-E) 
(Figure II) for the intestinal form of the disease.
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Vol. 38, No. 8,199!
Figure I: Percentage o f 8-10 year old children with S. haematobium at each school sampled, the prevalence 
figure is shown overlying the geographic location o f each school18
Figure II: Percentage o f 8-10 year old children with S. mansoni at each school sampled. The prevalence 
figure is shown overlying the geographic location o f each school.1*
317
CENTRAL AFRICAN
JOURNAL OF MEDICINE
Vol. 38, No. 8,1992
Sections were as follows; Section A: High prevalence 
zone: S. haematobium prevalence ranged from 13-97 
pc with a mean value o f 63,2 pc. This zone, which 
comprised the north-eastern area including Lake 
Kariba and Zambezi Valley, had high rainfalls and 
high temperatures w hich are ideal for high 
transmission of schistosomiasis.
Section B: M edium prevalence zone: The 
prevalence of S.haematobium ranged from a low rate 
of one pc to a high rate o f 85 pc with a mean of 37,1 
pc. This area comprised the south-eastern and central 
parts of the country which receive moderate rainfall.
Section C: Low prevalence zone: The rate of 
infection in this part ranged between zero and 44 pc 
with a mean of 14,3 pc. The area consisted of the 
western partof Zimbabwe and suffered from drought. 
Natural water bodies are rare and schistosomiasis 
transmission is very low.
Section D: A medium prevalence zone of S. 
mansoni: The average rate of infection was 15,2 pc 
in the north and south-eastern parts of the country.
Section E: A low prevalence zone of S', mansoni 
infection: The mean prevalence of one and a half pc 
was found in the rest of the country. The results 
reported above were further strengthened by the 
following malacological findings.
A survey of fresh water snails was done in 
Zimbabwe in the year 1988 by Makura and 
Kristensen.11 Their findings still to be published 
showed that Biomphalaria pfeifferi, intermediate 
host for S. mansoni, is highly prevalent in the 
north-east of the country. This correspondent with 
section D mentioned above. A light distribution was 
noted in the south east where there was a very low 
prevalence of the disease. Similarly, Bulinus globus, 
intermediate host snail for S. haematobium, was 
highly prevalent in the north-east and south-east of 
the country, with patchy distribution in the 
south-west. The distribution of the B. golbus snails 
matched that of S. haematobium infection in humans. 
PILOT PROJECTS SET UP TO CONTROL  
SCHISTOMIASIS: l.Schistosomiasis control in 
larger irrigation schemes: Schistosomiasis control 
in large irrigation schemes was practised for more 
than 30 years and considerable experience was 
gained from the large irrigation sugar estates in the 
low-veld.16 The main method used was snail control 
using niclosamide.9 Lately, mollusciciding has been 
supplemented by the use of ducks and devegetation
to reduce snail numbers.10 In addition, villagers are 
provided with safe water and sanitation facilities and 
health education lectures. Chemotherapy is rendered 
to people found infected.
These measures have managed to keep the 
incidence of infection to between zero and four and 
a half pc 10 where as the incidence is 45pc in other 
sch em es w here control m easures w ere not 
implemented.
2. Control in small holder irrigation schemes: 
The resettlement programme being undertaken by the 
Zimbabwe government has resulted in the creation of 
a number o f small-holder irrigation schemes. One of 
the most prominent is the Mushandike scheme which 
is situated 20 km south-west of Masvingo.5 Water for 
the farms is drawn from Mushandike dam and the 
main canal which was built in 1930. There is a single 
rainy season (November to March), irrigation is 
essential to supplement the low rainfall and to 
provide water during the dry season.5
Measures to control schistosomiasis were as 
follow s; a) Engineering designs. Engineering 
measures were aimed at preventing snail colonisation 
and breeding.1 This entitled lining of secondary and 
tertiary canals using concrete. In addition, certain 
hydraulic structures in the canal, such as sluice gates, 
weirs, and offtakes were implemented to reduce the 
damming effect which reduced water flow .7 
Furthermore, operational aspects of the irrigation 
works, regular drying of the canals, water level 
fluctuation in the storage reservoirs, routine 
maintenance such as removing stones or soil 
obstructions, weed clearance and preventing water 
seepage were incorporated to minim ize snail 
populations in the scheme.1
b) Environmental measures. Environmental 
control measures were aimed at reducing human 
water contact and contamination of surface water. ’ 
Villagers were sited as far away as possible from 
potentially infected water. Boreholes fitted with hand 
pumps were installed near each village and away 
from the dams and canals. Villagers were persuaded 
not to use canal water for domestic puiposes.5
Sanitation facilities in the form o f communal 
in-field pit latrines were built in the irrigated areas. 
People found infected at the start of the programme 
were treated to reduce contamination o f the 
environment and infection of snails.
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CENTRAL AFRICAN
JOURNAL OF MEDICINE
Vol. 38, No. 8,1992
Results of monitoring reported by Chandiwana et 
al,S showed that there was over 53 pc reduction in S. 
haemotobium prevalence from the time of the 
implementation of the control measures. Similarly, 
there were marked reductions (100 pc) in the 
prevalence of S. mansoni. No comparable reductions 
were recorded in an area where control measures 
were not implemented in spite of treating infected 
people.
The parasitology results above were supported by 
a reduction in both snail population densities and 
their infection rates.
3. Community based schistosomiasis control
project: A Primary Health Care (PHC) based
schistosomiasis control pilot project was undertaken
from 1986 by BRI. The main objective of the project
was to develop and eva lua te  an integrated
com m u n ity -b ased  sch is to so m ias is  con tro l
programme within the PHC system. Details of the
20programme arc reported elsewhere.
The study areas were at Madziwa and Bushu 
Com m unal Lands in Cham inuka D istrict of 
Mashonaland Central Province and the project was 
im plem ented through partic ipation with the 
following components:
A. Sanitation: The Madziwa community, agreed to 
build one Blair toilet per family, that meant a total of 
3 000 toilets had to be built. The programme was a 
success as 2 152 units were completed using self-help 
by the families.
B. Water Supply: The project aimed at providing 
one protected water point for every 25-30 families. 
Digging and maintenance of the pump was to be done 
by the community, while the Ministry of Health 
(MOH) provided the pumps. This programme was 
initially slow but by completion of the project, 104 of 
the targeted 150 boreholes had been completed and 
handpumps installed.
C. Health Education: Local health authorities and 
Village Community Workers (VCMs) had the task of 
educating the community on schistosomiasis and its 
relationship with hygiene, safe water and sanitation. 
The health message was well received.
D. Snail Control: A single application of a 
synthetic molluscicidc, (niclosamide) was applied at 
major water contact points and reductions in snail 
population densities were noted.
E. Chemotherapy: Chemotherapy was the only 
direct health service provided by the project staff, and 
was directed at infected school children. To monitor 
the effect of the control measures, parasitology 
surveys, for both .S’, haematobium and S. mansoni. 
were done yearly. In terms of overall achievement, 
treatment had a marked effect on prevalence. 
Incidence results showed that a community approach 
to the control of schistosomiasis was successful at 
Madziwa. Results of this project indicated that 
schistosomiasis control requires interdisciplinary 
collaboration, constant community participation and
unfortunately a major financial commitment from the
20already limited health budget.
Zhulube Schistosomiasis Control Project: Control
activities in the Matabclcland South province were
concentrated at Zhulube which has irrigation canals
12and a river running near the village.
The main thrust of the control strategy was 
improvement of water and sanitation facilities. Blair 
toilets were constructed and wells were upgraded. 
Swampy areas were turned into vegetable gardens.
Other control measures included health education 
which was targeted at school children who in turn 
passed the message to the parerus. In addition, 
infected individuals received treatm ent and 
mollusciciding was performed at water contact sites 
where infected intermediate host snails were found.
All these control measures contributed to a 50 pc 
reduction in the prevalence of S. haematobium. NoS. 
mansoni was detected in the area.  ^From the results 
of the pi lot  programmes,  a s trategy for 
schistosomiasis control has now- been established in 
Zimbabwe.
Zimbabwe Stra tegy for the Control  of 
Schistomiasis: The government of Zimbabwe has 
adopted a PHC-bascd strategy for schistosomiasis 
control and the broad objectives arc control of 
morbidity.  Within these object ives ,  a 
multi-component strategy, using snail control, safe 
water supplies, adequate sanitation and some aspects 
of snail control, are embodied within the PHC 
system.
The Basic Outline of the Control Strategy: The 
outline for the National Schistosomiasis Control to be 
done at Provincial level is shown in Tables I-11I.
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CENTRAL AFRICAN
JOURNAL OF MEDICINE
Vol. 38, No. 8,1992
Table I: Showing the activities to be undertaken during the preparatory phase (Problem analysis).
ACTIVITY T IM E  C O N D U C T E D
Administer questionnaire on know ledge and attitudes towards schistosomiasis 
Collection of necessary epidem iological, dem ographic and health services data.
Surveys ol safe w ater supplies and sanitation units.
Planning of operational and m anagerial structures 
Setting up of da ta  banks.
Definition of feasib le and effective long term  intervention m easures  
Training of peripheral health staff in diagnosis and control of schistosomiasis.
Training of m iddle level m anagers to  sustain the  program m e at province and district level.
August 1 9 9 2 -D e c e m b e r 1992  
August 1 9 9 2 -D e c e m b e r 1992  
June 1991-M a y  1992  
January 1 9 9 2 -J u ly  19 92  
July 1992
M a y  1 9 9 2 -J u n e  1992  
July 1992
M a y  1 9 9 2 -J u n e  1992
Table II: Showing activities during the intervention period.
A C TIVITY T IM E  C O N D U C T E D
Health education by peripheral health staff and school teachers in control of schistosomiasis  
Improving and providing safe w ater supplies sanitation units.
Selective chem atherapy of infected people.
From July 19 92  
From 19 92  onwards  
O ctober 1992
Table III: Consolidation and Evaluation (Phase 3)
A C TIV ITY T IM E  C O N D U C T E D
Consolidate and ensure that all the intervention m easures a re  maintained.
EVALUATION;
Administer a  questionnaire on knowledge and attitudes to schistosomiasis.
Conduct a  survey to  find the incidence, prevalence an d  intensity of hum an schistomiasis 
Undertake a  check-list of the w ater and sanitation units availab le  in each  area.
January 1 9 9 5  — D ec em b e r 1995
All programmes in this area rely on community 
participation  as the m ajor input in to  the 
implementation. The community is responsible for 
the provision of all labour, bricks and the long term 
maintenance of the facilities.19
DISCUSSION
The pilot projects and the Government strategy for 
schistosomiasis control will go a long way in 
reducing preva len ce  and m orbidity due to 
schistosomiasis infection in Zimbabwe.
However, there is still need for closer intersectoral 
co-operation betw een various governm ental 
departments, provinces, donor agencies, as well as 
closer integration between the schistosomiasis 
control programme and the ongoing PHC activities.
ACKNOWLEDGEMENTS
This review is published with permission of the 
Secretary for Health. The original manuscript was 
requested for the WHO expert Committee on the 
control of schistosomiasis.
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Progress in the control of schistosomiasis in Zimbabwe since 1984

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Progress in the control of schistosomiasis in Zimbabwe since 1984

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