Determinants of malaria in irrigated and non-irrigated villages of Mwea: a comparative assessment
Abstract
Today, approx:imately40% of the world's population, mostly those living in the poorest
countries,are at risk of malaria.l-' 'which causes more than 300 million acute illnesses and at
least one million deaths annually. Ninety per cent of deaths due to malaria occur in sub-
SaharanAfrica, mostly among young children. The importance of malaria cannot be overemphasized.
A project, (Agro-ecosystem Management for Community-Based Integrated
Malaria Control in East African Irrigation Schemes) is currently underway in Mwea
Division,Kirinyaga District, Kenya, under the auspices of the International Development
Research Centre (IDRC) Canada and the International Centre of Insect Physiology and
Ecology (lCIPE) in conjunction with the International Water Management Institute
(IWMI). The overall aim of this ICIPE-IWMI Project is to improve the health and wellbeing
of communities in irrigation schemes through the development of sustainable
strategiesfor reduction of malaria and other health risks based on improved agro-ecosystem
management. In Kenya, a considerable part of the area under irrigation is for rice
production. The choice of Mwea is appropriate since it provides an ideal setting in which
humanhealth can be factored into agro-ecosystem .research, thereby meeting the objectives
of the ICIPE-IWMI Project.
This cross-sectional descriptive study was part of the larger ICIPE-IWMI Project. Its main
objectivewas to compare malaria prevalence and to assess the potential environmental and
socio-economicdeterminants of the disease in irrigated (Ciagi-ini and Mbui Njeru) and non-
irrigated(Kagio and Murinduko) villages of Mwea. Quantitative data was obtained from
one cycleof malaria prevalence su.:rveys,undertaken in two villages within the irrigated area
thatwere matched with two control villages in the non-irrigated area beyond the flight range
of mosquitoes. This collective Malaria Prevalence Survey was carried out on 213 children
aged 9 years and under, in December 2001 and February 2002. The response rate was
74.5%. Qualitative data was obtained through participatory methodologies carried out
within the four villages and involved selected stakeholders and other target groups from
Mwea. In addition, a Community Diagnosis was carried out in 420 households within the
fourvillages.
Malariawas ranked as the major health problem in all the four study villages (except at the
Stakeholders'Consultative Workshop where it was ranked second). Within the irrigated
villages,malaria, alcoholism, and lack of clean water were the predominant problems.
Within the non-irrigated villages, the predominant problems were poor nutrition,
HIV/AIDS, lack of sewerage systems, poverty, and ignorance. Poverty was not perceived
asa problem at allwithin the irrigated villages but was a problem in Murinduko village in the
non-irrigated area. Kagio, also in the non-irrigated area, was perceived to be relatively
wealthy. Community Diagnosis generated inclusive quantitative household data on health,
incomes,and the environment. A comparison of results from quantitative and qualitative
data showed a high degree of consistency. However, an inconsistency occurred in Mbui
Njeruvillagewhere the qualitative data ranked malaria as the major health problem whereas
the quantitative data from the Malaria Prevalence Survey, which was conducted during the
wetseason,showed no positive cases of malaria.
The Malaria Prevalence Survey results showed that the overall prevalence for the four
villageswas 23.5 per 100. Within the irrigated villages, the prevalence was 6.7 per 100, while
in the non-irrigated villages it was 36 per 100, indicating that malaria prevalence was higher
within the non-irrigated villages than within the irrigated villages. Relatively more males
(68%)than females (32%) were positive for malaria parasites despite the roughly equal
distribution of the sexes. Malaria prevalence was significantly related to the age and
occupation of the household head, with those household heads that were that were in the
41-50year age group and those that were unemployed/reti:red having the highest p:roportion
of children with a positive blood slide. In addition,there was a significant relationship
between malaria prevalence and type of house. The majority (78%) of child:ren with a
positive blood slide lived in temporary structu:res. There was no significant relationship
between use of bed nets and a positive blood slide. However, there were significant
differencesin reported use of bed nets between irrigated and non-irrigated villages. More
respondents in the irrigated villages reported that all household members used bed nets as
compared to the non-irrigated villages. More respondents in the non-irrigated villages
reportedthat they did not use bed nets at all.
Therewas a significant relationship between the use of anti-malarial drugs in the preceding
three days and a positive blood slide. Most of the children who had used an anti-malarial
drughad a negative blood slide.
The averagenumber of Anopheles arabiensis mosquitoes in a house was significandy related to
irrigationand to a positive blood slide. There was also a significant difference in the average
number of Anopheles arabiensis mosquitoes in a house between irrigated and non-irrigated
villages. Houses that had a lower average number of Anopheles arabiensis mosquitoes had a
higherproportion of positive blood slides.
This cross-sectional survey only revealed the malaria situation at one point ill time.
Therefore, study that is more extensive is required in order to p:rovide a wider pictu:re of
malariain Mwea throughout the year. More research is necessary to explain the unusual
differencein malaria prevalence between irrigated and non-irrigated villages. More work: is
alsoneeded to investigate other findin~ such as the difference in prevalence between the
sexes,and between villages with a predominance of cattle and those with a predominance of
other types of livestock.
The symptoms of malaria are similar to those of other illnesses, notably typhoid, and this
may partly explain the apparent mconsistency between qualitative and quantitative data on
malariaprevalence observed in Mbui Njeru village.
Ecologicaldevelopment may have important effects on the epidemiology of vector borne
diseasessuch as malaria. This may be particularly significant where disease transmission is
unstablefor example, in highland areas. Intersectional partnership is necessary, such as was
the case in this study, in order to reduce the disease burden in Mwea. Understanding
communityperceptions of aetiology, symptom identification, and treatment of malaria is an
important step towards control of the disease.
Moredetailed and ongoing research is vital if lasting solutions are to be found. Research
projects should of necessity be participatory at all stages, such as was the case with the
ICIPE-IWMI Project, and even more importantly, continuous, because of the need for
monitoring,evaluation, and sharing of new information among concerned parties.
The residents of Mwea require empowerment in terms of acquisition of relevant health
education and sound economic and business principles in order to improve their socioeconomicstatus
and therefore be able to adopt malaria-prevention measures.
Citation
Oganda, M(2005).Determinants of malaria in irrigated and non-irrigated villages of Mwea: a comparative assessmentPublisher
Department of Community Health, University of Nairobi
Description
Master of Public health thesis