International Journal of HealthGeographicsReview Open AccessThe application of geographical information systems to importantpublic health problems in AfricaAbstractAfrica is generally held to be in crisis, and the quality of life for the majority of the continent'sinhabitants has been declining in both relative and absolute terms. In addition, the majority oftheworld's disease burden is realised in Africa. Geographical information systems GI!" technology,therefore, is a tool of great inherent potential for health research and management in Africa. #hespatial modelling capacity offered by GI! is directly applicable to understanding the spatial variationof disease, and its relationship to environmental factors and the health care system. $hilst therehave been numerous critiques of the application of GI! technology to developed world healthproblems it has been less clear whether the technology is both applicable and sustainable in anAfrican setting. If the potential for GI! to contribute to health research and planning in Africais tobe properly evaluated then the technology must be applicable to the most pressing health problemsin the continent. $e briefly outline the wor% underta%en in &I', malaria and tuberculosis diseasesof significant public health impact and contrasting modes of transmission", outline GI! trendsrelevant to Africa and describe some of the obstacles to the sustainable implementation of GI!. $ediscuss types of viable GI! applications and conclude with a discussion of the types of African healthproblems of particular relevance to the application of GI!.Background#he physical and ecological structure of Africa is as variedas its social, political and demographic characteristics ()*.+ajor biomes in the continent include tropical rainforest,montane forest, moist and dry savanna, semi,desert anddesert and temperate grasslands (-*. #he political environment,poverty and generally low levels of well,being forthe majority of the people in the continent combine withthe varied climatic conditions, vegetation and biogeographyto e.plain the prevalence of disease,causing organisms,or pathogens such as bacteria, viruses and worms(/*.#he applications of geographical information systemsGI!" to health and epidemiology have been critiqued bynumerous authors (01)/* and although found to be under,utilised it has been concluded that GI! has much tocontribute to the health sciences. &owever, it has beenless clear whether GI! technology is both applicable andsustainable in an African setting. GI! is a tool of great inherentpotential for health in Africa as health is largely determinedby environmental factors including thesociocultural and physical environment" which varygreatly in space. #he spatial modelling capacity offered byGI! is directly applicable to understanding the spatial variationof disease, and its relationship to environmental2ublished3 4 5ecember -66-International Journal of Health Geographics -66-, 130Received3 7 8ovember -66-Accepted3 4 5ecember -66-#his article is available from3 http399www.ij,healthgeographics.com9content9)9)90: -66- #anser and le !ueur; licensee td. #his is an ?pen Access article3 verbatim copying and redistribution of this article are permittedin all media for any purpose, provided this notice is preserved along with the article's original@R>.International Journal of Health Geographics -66-, 1 http399www.ij,healthgeographics.com9content9)9)902age - of 4(page number not for citation purposes)factors and the health care system ()0*. 2ublic health practiceneeds timely information on the course of disease andother health events to implement appropriate actions andGI! are an innovative technology for generating this typeof information. @nfortunately, the importance of the spatialdistribution of disease has been too often overloo%ed(7*.Africa is generally held to be in crisis and the quality of lifefor the majority of the continent's inhabitants has beendeclining in both relative and absolute terms()A*. #hehealth problems are different to those in the developedworld and if GI! is to be used for the health challenges facingAfrica, then it must respond to these realities and priorities.5ue to infrastructural and cost constraints, there isa lac% of reliable statistics and disease reporting in Africa.$here data do e.ist, they tend to be clinically as opposedto diagnostically" based. 5isease estimates in Africa cantherefore range between 'educated guesses and wild speculation'()B*. GI! can help significantly in this area by fillingthe gaps through empirical disease modellingtechniques.If the potential for GI! to contribute to health researchand planning in Africa is to be properly evaluated then thetechnology must be applicable to the most pressing healthproblems in the continent. In this article we focus on thehuman immunodeficiency virus &I'", malaria and tuberculosisas some of the most important public healththreats in Africa ()C,)7*as well as having diverse modes oftransmission. Durthermore we review wor% done in thespatial analysis of health systems that must assist in theattenuation and control of these diseases".Reie!Africa's health priorities&I'9AI5! is the leading cause of mortality and morbidityin Africa ()7*. !ince its appearance more than two decadesago the virus has spread to almost every country in theworld affecting an estimated /0 million people ()4*.8early -0 million people in Africa currently live with &I'9AI5! and the epidemic continues to ravage the developmentprospects for millions of Africans throughout thecontinent. In )444, about /.7 million Africans were infectedwith &I' during that year, and a total of )6.C millionchildren were estimated to be orphaned by it()A*. #he -)countries with the highest &I' prevalence are in Africa. In!outh Africa, ow cost units can now perform tas%s thatthey previously weren't suitable for. #his development isli%ely to result in a sharp increase in the number of georeferencedhealth projects ma%ing use of G2! technologyin the near future.Obstacles to the advancement of GIS in health in Africa#he paucity of qualified staff, which has prevented manyGI! projects from surviving the donor involvement phase,is a major problem in Africa (C7*. GI! applications in Africaare often found to be initiatives funded or supportedby international aid agencies and many are pilot or researchprojects as opposed to operational systems. #heyalso tend to be controlled by outsiders, not by African scientists(C4*. If GI! are to be useful and effective, then theymust be introduced by local scientists who understandboth the technological and the socio,economic conte.t inwhich the systems are to operate. #raining creates capacityand leads to an increase in terms of data needs. It howeveralso provides the capacity to fulfil these needs and the newproducts that result are often of value to many other sectors.=apacity development of African staff should thereforebe prioritised.In addition to lac% of capacity, a lac% of suitable GI! datasets is a major impediment to the growth of GI! in Africa.#he access to spatial data which are fundamental to anyGI! application" continues to be difficult and e.pensive()6*. #his is not specific to health but to all sectors thatutilise GI!. #here are similarities in the field requirementsfor using GI! between forestry, ecology, archaeology andepidemiology that could provide substantial benefits bythe sharing of e.periences and the pooling of resources())*. &owever, much of the spatial data collection effortswithin Africa have been conducted in a decentralisedand uncoordinated manner. Inter,sectoral collaborationinitiatives should therefore be encouraged and receivefunding priority. Africa could usefully build projects suchas the Global !patial 5ata Infrastructure(76* embeddedwithin which is the !5I 1 Africa project" and the GI! 1 Africa(7)* projects which aim to support ready access to geographicinformation to support decision ma%ing at allscales for multiple purposes. Geographic datasets are beingdeveloped for some countries in Africa through theseinitiatives, but a systematic programme is required toma%e geographic data readily available for the continentas a whole. A major programme funded by an internationalbody" is needed to ta%e up this challenge. 2rioritiesinclude, for e.ample, the digitalisation of )3-A6 666 and)3 A6 666 cartographic maps for countries that have them.!imilarly, national geo,referenced health facility databasesshould be established. Ine.pensive African data sets includethe African data sampler topographic, boundaryand place data"(7-*, long,term rainfall and temperaturedata (7/* and raster population data (70*. 5evelopmentof such data sets are of paramount importance to ensurethe growth of all sectors of GI! in Africa.$idespread availability of small scale digital data H )3 A6666" for many countries within Africa is unli%ely to everbecome a reality. #he most cost,effective answer to thedata deficit and poor vital registration and health statisticsproblem in Africa is the establishment of sentinel geo,referenceddemographic and health surveillance systems(7A*. #his will enable the elucidation of small,scaledisease patterns e.g. diffusion dynamics" that could bemodelled using coarser resolution data and the coveragee.tended. #he I85G2#& networ% is a networ% of thesesentinel surveillance sites, -/ of which are in Africa(7B*.#he sites follow up a designated population intensivelyover time collecting highly accurate demographic, vitalevent e.g. births, deaths, migrations" and health data ona routine basis. !o far only a small proportion of the sitesare fully geo,referenced but this is li%ely increase with theincrease in G2! accuracy, falling prices and the obviousoperational and research advantages of fully geo,referenceddata. #hese sites can especially contribute and havealready contributed" to our understanding diseases withill,defined relationships to the environment due to the detailedlongitudinal collection of disease covariates. A recentspatial initiative in health is the $est African !patialAnalysis 2rototype $A!A2" that used geo,coded demographicand health survey 5&!" data to study the effectsof climate on children's nutritional status, and the relationshipbetween economic diversity and reproductive behaviour,as well as study the subnational geographicvariation in health indicators at a regional level(7C,77*.Dollowing the success of $A!A2, more 5&! sites have beganto geo,code their survey data in an effort to facilitatecross,disciplinary analyses. #he increasing availability ofregional geo,referenced 5&! data will facilitate a morecomprehensive understanding of the patterns and processesof demographic and health changes and will lead toan increasing amount of GI!,based analyses of this importantdata in the near future.In addition to the geo,coded household datasets outlinedabove, a large number of remotely sensed data sets, whichhave been already used e.tensively in health are availablefree of charge or at nominal cost. $ith the emergence ofnew technologies and techniques within remote sensing,there is li%ely to be a great improvement in the quality ofsuch data sets and parallel improvement of GI! and relatedresearch products(74*. 8evertheless, it is also true tosay that so far, our ability to e.tract meaning and ma%eInternational Journal of Health Geographics -66-, 1 http399www.ij,healthgeographics.com9content9)9)902age B of 4(page number not for citation purposes)useful decisions from remotely,sensed data has not %eptpace with the developments in this field.#he issue of scale is one that is poorly understood in thedisease arena. 5isease patterns and processes evident atone scale are not necessarily evident at another. +oreover,correlations between e.planatory variables and outcomesmay even be seemingly" reversed at different scales. #hishas led to a significant amount of confusion when hypothesesare rejected at one scale and not at another.!ometimes it is advisable to use coarser resolution data tomas% out small scale heterogeneity. Dor e.ample, the malariamodelling at a continental level used climatic data ata resolution of 6.6AN (/-,/0*. &igher resolution satellitedata sub %ilometre" may obscure continental malariapatterns by e.posing unnecessary small area variation.Ideally the resolution of the data should be driven by theapplication. &owever, given Africa's geographic data deficits,future research is needed to establish how applicablecoarse resolution data sets are to modelling high resolutiondisease,specific dynamics and vice,versa. #he aboveissues are as applicable to temporal resolution as they areto spatial resolution.Another obstacle remaining to the growth of GI! in healthin Africa is to convince role players often from cashstrappedorganisations" of the proven cost,effectiveness ofGI! in the health arena(46*. Gven amongst the internationalscientific community, significant scepticism still e.istssurrounding the use of GI! technology in health. #hisproblem will diminish in siLe as GI! continues to evolve.#he parallel with epidemiology again warrants mentioning3In the same way that scepticism greeted epidemiologistswho hypothesised that a relationship e.istedbetween smo%ing and lung cancer in the )4A6s (CC*, so towill scepticism continue to plague GI! until it is firmly establishedas a science.It is encouraging to note that several of the issues cited asobstacles to the growth of GI! in Africa a decade ago (4)*have been overcome to some degree. #hese included theincompatibility of different software formats data conversionproblems", the non user,friendly interfaces ofmany systems and the lac% of good ine.pensive9free GI!software. ?ther obstacles such as the prohibitive costs ofhardware have also become less of an issue. 2erhaps a reviewin a decade's time will describe the increasing availabilityof ine.pensive spatial data sets for AfricaO#he 'mapping malaria ris% in Africa' +ARA" research collaborationis an African research endeavour that ma%es e.tensiveuse of GI! technology. #he collaboration has beenhighly successful in collating malaria data from aroundthe continent, and producing a large number of scientificpublications on a limited budget. #he outputs of the researchwere then disseminated to countries throughoutAfrica in the form of digital via the stand,alone +ARA litesoftware" and hard copy maps. #he collaboration overcamesignificant data deficits by creating its own base datasets and created a significant amount of GI! capacity in itsfive regional centres throughout the continent. 5uring thesetting up of the collaboration, significant scepticism wase.pressed by influential malaria scientists as to the ultimatevalue of a GI! approach, its logistical feasibility andcost,effectiveness(//*. #he collaboration is a testament tothe fact that successful GI! initiatives can be underta%en inAfrica.Viable GIS health applications in Africa#he current software and hardware trends in combinationwith the realities faced in Africa have given rise to essentially,two broad categories of long,term feasible GI!health applications in Africa. #he outputs of the categorieswill inform one another and are not mutually e.clusiveand may overlap. #he first category involves the use of GI!as a research tool. #hese applications should see% to providenew insights into the spatial dimensions of diseaseand new methodologies to more cost,effectively allocateresources to health services. #hese types of applicationswill normally use high,end systems with significant analyticalfunctionality and will usually involve a significantamount of additional data collection.#he second category of long,term viable GI! applicationconcerns the use of GI! as a health planning and managementtool and for e.ploratory data analysis. Generallyspea%ing this %ind of system will involve a low,end GI!.#he primary goal of such a system will be to simply displayand overlay basic health data concerning both healthcare facilities and disease patterns. #hese systems normallyvector,based" permit rapid manipulations of spatialdata and display of the results so that the decision ma%erscan use them for policy decisions. A further step could involvelimited spatial queries and analysis such as buffering.#he outputs of the different categories of application willinform one another. As the data is geographically displayedusing a management GI! and research questionsare derived, collaborations can be initiated with institutionsunderta%ing GI! research to test hypotheses andmodel disease distributions. !imilarly, research GI! applicationswill inform GI! management applications to planoptimal resource allocation and intervention strategies,for e.ample. #he +ARA collaboration is a successful e.ampleof this type of approach and is embedding severalof its research outputs in the freely available GI! software&ealth+apper developed by $&?" for interventionplanning in Africa at a district level.International Journal of Health Geographics -66-, 1 http399www.ij,healthgeographics.com9content9)9)902age C of 4(page number not for citation purposes)"onclusionsA review of the health literature in Africa reveals the GI!bias towards so called 'environmental' diseases. In certaindiseases, such as the vector,borne diseases e.g. malaria,schistosomiasis, human helminth infections and trypanosomiasis"the environmental component in the determinationof factors such as transmission intensity ise.tremely high. In other diseases, especially in the noncommunicablecategory e.g. multiple sclerosis" lin%s tothe environment are wea% or non,e.istent. !ome infectiousdiseases such as &I' and tuberculosis have moderatelystrong lin%s to the environment. #hus there e.ists acontinuum of diseases, on the one end there are those diseasesin which GI! has limited research application andon the other there are those in which GI! is highly applicable.#his continuum does not relate to the availability ofancillary data sets but rather to the inherent nature of thedisease itself.8ot only does Africa have the highest burden of disease ofall the continents()7*, but it is the continent in which thegreatest component of the burden is contributed by socalled 'environmentally dependent' diseases. In addition,the phenomenon of climate change is li%ely to hit hardestin Africa ()A* on account of its greater rainfall variabilityand the proportion of 'ecothermic infectious diseases'.#his ma%es the potential applications of GI! in health particularlyrelevant to Africa, i.e. GI! in health has greaterrelevance and inherent potential in Africa than it does inthe @nited !tates or Gurope for e.ample. @nfortunately,this reality is not reflected in the literature or in practice.#hus, we concur with authors (4-,4/* who have concludedthat GI! is an appropriate technology for developingcountries despite the fact that in some ways GI! appearsto contradict the principles of appropriate technology becauseof its sometimes high cost and often high levels ofe.pertise required" since many issues of poverty relate tolarge scale problems requiring integration of large spatialdatasets. Durthermore, the success of participatory approachesfor the transfer of GI! technology by the +ARAproject and in other developing country settings (40*could serve as a useful framewor% for future projects.#he ability to map spatial and temporal variation in diseaseris% is more important than ever given the ever,increasingdisease burden in Africa. GI! allows the planningof control strategies and the delivering of interventionswhere the need is greatest, and sustainable success is mostli%ely. 5espite some obstacles, GI! holds considerablepromise for health research and development in Africa.#he global trend towards faster, more powerful computers,user,friendly software and falling prices combinedwith the magnitude and nature of Africa's disease burdenand lac% of reliable disease statistics ma%es it a viable, relevantand powerful technology for health research andmanagement in Africa.#ist of abbreiations5&! 1 5emographic and &ealth !urvey5?# 1 5irectly observed treatmentGI! 1 Gnvironmental Information !ystemsG2! 1 Global 2ositioning !ystem&I' 1 &uman Immunodeficiency 'irus+ARA 1 +apping +alaria Ris% in Africa!5I 1 !patial 5evelopment Initiative$A!A2 1 $est African !patial Analysis 2rototype$&? 1 $orld &ealth ?rganisationAuthors$ contributions#he authors contributed equally to the conceptualisationand writing of the manuscript.Ackno!ledgements5avid le !ueur died une.pectedly during the advanced stages of manuscriptpreparation. Dran% #anser wishes to ac%nowledge him for conceiving anddriving the +apping +alaria Ris% in Africa +ARA" initiative and for his unsurpassedlifetime contribution to the field of malaria mapping and modellingand to GI! in health in general. #his research was jointly funded by the!outh African +edical Research =ouncil and the $ellcome #rust.References). Ialipeni G Health and disease in southern Africa% a comparatieand ulnerability perspectie& Soc Sci Med -666, '(%4BA,7/-. !toc% R Africa )outh of the )ahara% a geographic interpretation&Ne !or"# Guilford Press )44A,/. Iloos & and Eein EA The ecology of health and disease in *thiopia&$oulder% &olarado# 'est(ei Press )44/,0. 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