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1. Introduction

1.1. Back ground of the study

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Malaria is a
vector-borne disease caused by protozoan parasites belonging to the genus
Plasmodium and transmitted by the bite of infected female Anopheles species mosquitoes;
about 60 species of the genus Anopheles can transmit malaria (Walker K,
2002, Cox FE.2010). Until recently, five species of Plasmodium, namely: P.
vivax, P. falciparum, P. ovale (two sub species: P. ovale curtisi and P.
ovale wallikeri), P. malariae and P. knowlesi are known to cause
human disease (Cox-Singh J, 2010; Yusof R;,et al., 2014). The conditions of the
parasite, vector and the human host are characterized by different factors,
which are highlighted here.

 

It is caused by
Plasmodium parasites, is a blood-borne disease which is transmitted through the
bite of an infected female Anopheles mosquito. It is a major public health
issue which affects the global population at large (Kumi-Boateng et al.,
2015; Ahmed, 2014). Malaria is typically found in warmer regions of the world, i.e.,
the tropical and subtropical countries. Vectors (female Anopheles mosquitoes)
require specific habitats with surface water for production, humidity
for adult mosquito survival and the development rate of both vector and
parasite are dependent on temperature (Ahmed, 2014; Ashenafi, 2013).

 

 Malaria is essentially an environmental
disease since the vectors require specific habitats with surface water for
reproduction, humidity for adult mosquito survival and the development rates . The
increase in malaria prevalence is determined by several factors: mosquito
resistance to insecticides, parasite resistance to drugs, changes in land-use
patterns, and reductions in funding and manpower dedicated to control
activities. Most of the determinants are heterogeneously distributed, changing
over both space and time. Factors such as topography, temperature, rainfall,
land use, population movements, and degree of deforestation have a profound
influence on the temporal and spatial distribution of malaria vectors and
malaria. (FMoH, 2009).

 Globally, about half of the
world populations (3.3 billion) are at risk of malaria infection (World
Health Organization WHO 2011).Adult female
mosquitoes of the genus Anopheles are vectors for the Plasmodium parasites and
are thus responsible for malaria transmission.

 

There are 490 species in the genus Anopheles, and 70 of these are
vectors of malaria. In sub-Saharan Africa, there are 140 Anopheles species of
which approximately 20 are known to transmit malaria parasites to human beings.
Of these, Anopheles gambiae s.s, Anopheles arabiensis Patton, and Anopheles
funestus Giles are the most widely distributed and important malaria vector
species in tropical Africa (Gillies and Coetzee 1987, Foley et al. 2010).

 

 According to Kaya et al. (2002), malaria
remains one of the greatest killers of human beings, particularly in the
developing countries. The World Health Organization (WHO,2012), estimated over
one million malaria cases each year, where more than 80% of the cases are in
Sub-Saharan Africa countries.

Malaria
is one of the main health problems in Ethiopia in which its cases are one of
the highest and it is increasing in an alarming rate. Ethiopians live at
altitudes ranging from ?100 to >4220 m, the topography made a fertile ground
for the reproduction of the epidemic. More than 50 million (68%) of the
population live in areas below 2000 m above sea level are at risk of malaria.
With consequent variation in minimum and maximum temperatures. In general, the
main reasons given for the increment are ecological and climatic changes. The
peak of Malaria incidence follows the main rainfall season in July, August,
September, October and November each year. (Negassi F., 2008).

Currently
Remote Sensing techniques provide valuable information on such environmental
conditions. Several studies have used Remote Sensing imagery and Geographical
Information System (GIS) techniques to map the distribution of vector species
at different spatial scales such as the entire world, continent, national,
regional, even at small village level. According to Tran et al (2008),
in endemic areas, mainly in tropical and subtropical regions, these vector maps
are designed to improve vector control, which is currently one of the essential
methods in limiting the burden of important vector-borne diseases such as
malaria or dengue fever. In disease free areas, analyzing the link between the
environment and potential vector distribution may help evaluate the risk of
emergence of the disease, and lead to better mitigation and control measure of
the invasive vector species. In particular, the evolution of geographic
information systems (GIS), the global positioning system (GPS), and remote
sensing (RS) technologies has enabled the collection and analysis of field data
in ways that were not possible before the advent of the computer(Milla et al.,
2005).

GIS
has several applications to the study of mosquito biology and ecology (Eskinder
etal., 2010), suggesting that GIS is the best or available method to answer
questions regarding mosquito ecologyas well studies of risk as a function of
distance from known breeding sites and others are one common application of
GIS. GIS in combination with remote-sensing (RS) technology, has also been
employed to predict areas of high productivity of mosquitoes and potential
malaria epidemics based on the detection of proxy ecological variables (Hay et
al., 2000). Therefore, the aim of this study will be to assess the spatio
temporal variation of malaria in the study area

 1.2. Statement of the of the
problem

Globally, about half of the world populations (3.3 billion) are at
risk of malaria infection (World Health Organization WHO
2011). It has widely known impacts on the
economic, social, and political sphere of the society As a result wide range of
measures were taken by national and international organizations to reduce the
impact of the epidemic but most of the efforts were invested on managing the
results than prevention. Therefore, the cost of preventive plan and medical
treatment becomes affect the GDP and as well as the individual economy due to
this infections.

An
estimated numbers of billion peoples are at risk of this infections and 3000 to
5000 million suffering a short period with the disease each year perhaps 90
percent of these occur in tropic of Africa (WHO, 2012) Malaria kills between
1.1 and 2.7 Million people per year. Of these deaths, approximately one million
are children in the tropic of Africa between the ages of 18 months and 5 years
(Webb, 2009).

 Malaria risk becomes higher
developing countries (Donnelly, 2005). According to Stratton, (2008) mentioned
the multiplicity of malaria causing factors in semi urban areas as the main
cause of its prevalence as they are difficult to control at the same time.

 

 Due to its tropical location and availability
of many rivers and lakes, Ethiopia is suitable for breeding of plasmodium (Womie,
2008). As aresult it is a major public health problem in Ethiopia (FMoH, 2009).
Accordingly its occurrence in most parts of the country is unstable mainly due
to the country’s topographical and climatic features.

 

 

 

 

In
order to reduce this impact of the epidemic disease, wide range of measures
were taken by national and international organizations. Preventive measures are
cost and time effective.

One
of the Maine issues to be considered as preventive is to work on the main
factors contributing for the development and expansion of the problem. In this
case Geographic Information System and Remote Sensing (GIS AND RS) application can
best fit to analyze the root problem both spatially and temporal variation. For
this reason, understanding malaria epidemics using GIS and Remote Sensing data
believed to be essential by the researcher.

 

As
a result, in the study area, the spatial variation of malaria risk level based
on environmental factors is not identified, which could facilitate the malaria
prevention and control activities. To feel this gap, the researcher will try
applying the application GIS, RS and MCDE based analysis to identify,
classifying, and mapping areas vulnerable to malaria epidemic.

1.3.
Objective of the Study

The
study will be carried out to achieve the following objectives.

1.3.1. General objective

This
study aims to optimize the use of GIS and Remote Sensing (RS) technologies in
malaria control programme by examining the spatial distribution of vectors in
malaria endemic areas and determining the correlation between environmental
variables and the distribution of larval in the breeding habitats.

1.3.2. Specific objective

ü  To
investigate the trends of malaria in the study area.

ü 
To identify and integrates environmental
(topographic) factors which make condition suitable for facilitating mosquito
breeding conditions.

ü 
To analyze the spatial distribution of malaria
epidemic in the study area

ü 
To develop malaria risk map of the study area

ü 
To compare malaria risk level of the  selected weredas in the study area

 

1.4. Research questions

Considering
the above listed research objectives, the following research questions will be
used as the fundamental basis for this study:

1,What
is the temporal change of malaria infestation in the study area?

2,
What are environmental factor which provides mosquito breeding conditions.

3, How
the malaria infestation is distributed over the space of the study area?

4,
Which parts of the the selected weredas have high, moderate and low malaria
risk levels?

1.5.
Significant Of the Study

The
result of this study could give important information on the spatio-temporal
distribution of malaria case in the study area. The study will have also  the ability of identifying risk areas using
GIS and remote sensing technique that greatly enhance the effectiveness of
prevention efforts and will contribute to cost-effective prevention method by
providing mechanism of efficiently targeting high risk areas, which help
national and international organizations, medical geographers and any stake
holders working in the health and the selectedweredas of  health sectors in organizing their efforts
towards the fight against malaria efficiently and cost effectively.

1.6. Scope
of the Study

The
scope of this study is delimited both in geographical area and issue of
concern. Geographically, it is delimited to the two selected woredas of Jimma
zone which is Limmu seka and choraboter of Oromia national regional state.
Regarding the area of concern, the main focus of the research will developing the
spatioal variation of malaria risk map for the Woredas. Thus, this study is
restricted to develop GIS and remote sensing based malaria risk map of the
study area using environmental factors.

1.7.
Organization of the paper

The study will have five chapters the first chapter contains
introduction, statement of the problem, objectives, and research question: in
the second part theoretical literature will reviewed and the third chapter
contains methodology and description of the study area. The fourth chapter
deals with result and discussion, in the last chapter conclusion and
recommendation will be forwarded.

 

               

CHAPTER TWO
2. LITERATURE REVIEW
2.1. Global Concepts and Distribution of Malaria

Malaria
is an ancient disease caused by parasites of the genus Plasmodium and
transmitted by several species of female anopheles mosquitoes. The term
‘malaria’ originates from malaria (Italian) signifying ‘bad air’ or miasmas
arising from marshes (Shumbullo, 2013).

 

Protozoan
parasites of the genus Plasmodium are responsible for human malaria, of which
four species are primarily involved, plasmodium falciparum, Plasmodium vivax,
Plasmodium malaria, and Plasmodium ovale. Recent reports have suggested the
possibility of a fifth species, Plasmodium Knowles, as an important and common
emerging zoonotic pathogen responsible for human infections in Southeast Asia
(Cox-Singh et al., 2008).

 

Globally,
P.falciparumis the most common cause of malarial infection, responsible for
approximately 80% of all cases and 90% of the deaths. Plasmodium transmission
from Anopheles vector to humanism accomplished through direct injection of the
parasite contained in salivary gland fluid during blood feeding. Of the
484recognized species of Anopheles (Harbach, 2004), only about 20% orless are
generally involved in malaria transmission (Bruce-Chwatt, 1980). Anopheles
females become infected by imbibing sexually mature gametocytes present in the
peripheral blood of the host. In the mosquito midgut fertilization produces the
ookinete which traverses the mosquito gut and forms oocytes under the outer
most layer of the gut wall. After repeated multiplication, each oocyst
eventually ruptures releasing hundreds of sporozoites into the mosquito body
cavity, a proportion of which will invade the salivary glands awaiting the
opportunity to infect another human upon the next blood feeding by the
mosquito. Thissporogonic cycle (ookinete–oocyst–sporozoite) within the mosquito
takes on average 10–14 days depending on the ambient temperature and Plasmodium
species. Infective female mosquitoes will generally remain infectious during
their entire life which is spent repeating a cycle of blood feeding, developing
and lying eggs every two to three days per gonotrophic cycle.

 

According
to WMR (2009), the global numbers of malaria cases in 2008 were an estimated
243 million. The vast majority of cases (85percent) were in the African Region,
followed by the South-East Asia (10percent) and Eastern Mediterranean Regions
(4percent). And it accounted for an estimated 863,000 deaths, of which
89percent were in the African Region, followed by the Eastern Mediterranean
(6percent) and the South-East Asia Regions (5percent). Each parasite has a
distinctive appearance under the microscope, and produces a somewhat different
pattern of symptoms (NIAID, 2007).

 

Their description is given as. The infection can develop suddenly
and produce several life threatening complications. With prompt, effective
treatment, however, it is almost always curable (NIAID, 2007). Plasmodium vivax: the most
geographically widespread of the species, produces less severe symptoms.
Relapses, however, can occur for
up to 3 years, and chronic disease is debilitating. Once common in temperate
climates, Plasmodium vivax is now found mostly in the tropics,
especially throughout Asia (NIAID, 2007). A person asymptomatic (no symptoms) Plasmodium
malaria, however, can 8 infect others, either through blood donation or
mosquito bites. Plasmodium malaria has been wiped out from temperate
climates, but it persists in Africa (NIAID, 2007). Plasmodium ovale: is rare, can cause relapses, and generally
occurs in West Africa (NIAID, 2007)

2.2. Global
distribution of malaria

Malaria
is one of the world’s most common and serious tropical diseases. However, on the globe, it extends up to 60° north and
40° south of latitudes. Its distribution in the world is not uniform. Different
species of Plasmodium are found in different countries. According World Malaria
Report of 2012, about 70-90 per cent of the risk of malaria is considered due
to environmental factors which in turn influence the abundance and survival of
the vectors.

 

This
has motivated the World Health Organization to pursue the development of new
techniques and models in which the role of environmental is fundamental.
Spatial technology helps systematic and regular monitoring of the earth’s
environmental conditions furnishing large amounts of spatial and temporal data.
Such information together with appropriate field studies can prove very
fruitful for early detection and timely response to disease management.

 

About
90% of all malaria deaths in the world today occur in Sub Sahara Africa
countries. This is because the majority of infections in Africa are caused by Plasmodium
falciparum, the most dangerous malaria species of the four types. It is the
most widespread in Africa and the most difficult to control. About one million
people in Africa die from malaria each year, where most of them are children
under 5 years old (WHO, 2011).

 

According
to World Malaria Report of WHO, 2012, the global malaria distribution has
progressively been reduced since the mid 19thAccording to World Malaria
Report of WHO, 2012, the global malaria distribution has progressively been
reduced since the mid 19th century, especially from 1945 to 1977,
when 37 countries were freed of malaria thanks to the efforts of the global
eradication programme. Success in malaria elimination occurred mainly in
countries in Europe and North America, where malaria transmission was lower.
Even today, the 11 countries which are aiming at malaria elimination have low
malaria transmission and are placed at the limits of the global map of malaria
distribution (NIAID, 2015). Century, especially from 1945 to 1977, when
37 countries were freed of malaria thanks to the efforts of the global
eradication programme. Success in malaria elimination occurred mainly in
countries in Europe and North America, where malaria transmission was lower.
Even today, the 11 countries which are aiming at malaria elimination have low
malaria transmission and are placed at the limits of the global map of malaria distribution
(NIAID, 2015).

2.3. Distribution of
malaria in Ethiopia

The
existence of malaria in Ethiopia is unquestionable due to its tropical
location. Besides its tropical location, 75% of the area that lies below 2000 m
a.s.l elevation, where about two-third of the population is living on is also
provides favorable natural environment for the occurrence of malaria and hence
it is malarious (Woime, 2008).

 

In
Ethiopia, the estimated incidence rate for malaria (i.e., the estimated
probability of contracting the disease in a year) is 15%, which is low relative
to the rest of sub-Saharan Africa (Where the average incidence rate is 0.33),
but higher than any other country outside of sub-Saharan Africa, Panama, Laos,
Myanmar, and the Solomon Islands (WHO, 2012).

 

Despite
the somewhat low incidence rate, this country is an appealing place to do a
study on malaria for at least two reasons. First, malaria is still a very
important public health problem: Ethiopia is thought to experience some 10
million cases per year, the fourth highest case numbering sub-Saharan Africa
(behind Nigeria, the DRC, Tanzania, and Uganda (WHO, 2012).The second reason
for considering malaria in Ethiopia is that, unlike most other African
countries, there is extensive local variation in malaria incidence.

 

Among
plasmodium species, Plasmodium falciparum and Plasmodium vivax are
the most dominant malaria parasites in Ethiopia, distributed all over the
country and accounting for 60% and 40% of malaria cases, respectively. Plasmodium
malaria accounts for less than 1% and Plasmodium ovale is rarely
reported. The parasite is principally transmitted by the major mosquito vector
known as Anopheles arabinoses. In
some areas, Anopheles pharoensis, Anopheles funestus and Anopheles
nili also transmit the disease (Adugna, 2011).

 

In
Ethiopia, malaria has a personality, geographic character, and impact quite
different from other parts of Africa and global malaria (Getachew et al.,2010)
they put forward, Ethiopia’s malaria is unstable-the high seasonal fluctuations
in temperature and moisture result in malaria appearing in epidemic form and
with great variation across landscapes. The instability of Ethiopia’s malaria
means that populations in most areas have never attained a significant level of
protective immunity (ashas been the case in endemic areas of West Africa) and
thus a higher rate of death and morbidity among adults.

 

In
each of those early to mid-twentieth-century analyses medical field
observations confirmed Ethiopians’ own folk epidemiology about malaria as an endemic
disease of the moist lowlands and river valleys and its highly seasonal
character that followed closely the annual life cycle of its mosquito vectors
(FMoH 2009). The malaria landscape followed closely elevation, slope and the
seasonal cycle of temperature and moisture (Getachew et al., 2010).

 Ethiopia’s malaria is also distinctive in the
dominance of the parasite P. falciparum, a particularly deadly form, and
particularly the prevalence of the mosquito vector A.arabiensis, a
species of anopheles mosquito that has over time and changing ecologies adapted
its behavior and habitat preference for the high seasonal variation of East
Africa andsahelian zones where unstable malaria is the dominant form (Asnakew,
2002).

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