water sources, infrastructure, space and the dynamics of ...

Matthew Biniyam KursahTRITA LWR Master ThesisSpace and incidence of malariaThis section presents and analyses results of the correlation betweendistances to the main town, watercourses, roads, the type of land coverand elevation on one hand and environmental diseases on the other.Table 13 shows correlation between malaria and distance to the maintown (district capital). The rationale behind this was to find out whetherdistances to major town which is the hub of health, educational, social,economic and political activities in the district have any relationship withthe occurrence of Malaria incidences. The premises are that; 1) the majortown serve as the district capital with relatively better water managementsystems, 2) majority of the most educated (defence mechanism) peopleare found in the major town, and 3) poverty is dominant in the ruralareas than the major town (hub of economic activities). However, Table13 shows that Malaria and distance to major towns (including majortowns in neighbouring districts) have an inverse correlation withsignificance of 0.001 levels. This can be explained by six main reasons; 1)the relatively dense population in Saboba township and high number ofpersonal-house ownerships (Table 15) created so many dugout pits formosquitoes to breed, 2) the dilapidated and open gutters found in themajor town serve as good grounds for mosquito larvae to grow, 3) thereare more open containers such as used cans, broken bottles etc inSaboba township than in the peripheries due to higher population, 4)relatively low hospital attendance of the peripheral areas due totransportation difficulties, illiteracy etc, 5) the open type public toilets (Fig.15) are only available in the major town; these toilets serve as reservoirfor breeding mosquitoes, and 6) the township has a poorer sanitationthan the periphery.Table 14 shows that the relationship between Malaria and distance toroads also has an inverse relationship with a significance level of 0.026.This means that more Malaria cases are reported close to road networks.However, the closeness to roads in itself does not directly determine thepresence of stagnant water to facilitate breeding of mosquito (anopheles)larvae but rather 1) the concentration of large population along roadnetworks means more dugout pits as a results of the need for buildings(Fig. 1), 2) the gutters constructed along road networks and the potholesfound on these third class roads in the district may have served asbreeding grounds for mosquito larvae, and 3) low hospital attendance ofthose in the periphery due to transportational difficulties; account forthis relationship. This shows that Malaria is largely an urban health problemin the district.With a significant level of 0.108 and correlation of -0.190, Table 15shows that there is no significant correlation between incidence ofMalaria and distances to conventional water sources (river and streams).Three main reasons explain this surprising result. Firstly, the more visiblewater bodies are rivers and streams with flowing current – such flows donot facilitate high breeding of mosquitoes. Secondly, the usuallytemporary, small, stagnant and open grey water bodies which facilitatethe growth of mosquitoes are not shown in the GIS analysis. Thepresence of water does not necessarily make it breeding grounds formosquitoes, but rather the prevailing condition of the water. The thirdreason that explains this otherwise surprising result is the length ofexposure of intermittent rivers and streams to the breeding ofmosquitoes. Though, these watercourses do dry-out and “cut” at someof its sections, which could facilitate the breeding of mosquitoes, it ishindered by the differences in the timing of the dry-out period (around42