The irrigation farming methods on the Makhathini Flats are thought to be
responsible for recent increase in malaria cases in the Mamfene area of
northern KwaZulu-Natal despite ongoing malaria control activities. Their
coincidence with the period of intensive fanning is an interesting one. This
study was therefore carried out to determine the relationship between larval
habitats and adult mosquito population in malaria transmission using
Geographic Information System (GIS).
Four types of breeding sites were utilised by malaria vectors in Mamfene, viz;
types 1, II, III and IV. Habitat type I was tap pools, type II was irrigation
spillage in agricultural land, type III was spillage outside but adjacent to the
agricultural land and type IV was depression pools located both in the
Balamhlanga swamp and inland. The cumulative larval density in all habitats
peaked in March 1995 (20/man-hr), with irrigation spillage (type III) recording
the highest density index (33/man-hr) as compared to tap pools (type I) which
recorded 32.8/man-hr while other waterbodies recorded I3 .4/man-hr (type II)
and O.5/man-hr (type IV) respectively. Subsamples of both larvae and adults of An. gambiae group were identified by
the Polymerase Chain Reaction (PCR) technique. Of the larvae identified,
94.1 % and 5.9% (n=289) were An. arabiensis and An. quadriannulatus
respectively while in the adult component, the composition was 98.7% and
1.3% (n=303) for An. arabiensis and An. quadriannulatus respectively. This
confirmed An. arabiensis as the dominant malaria vector in Mamfene area
while the exophilic behaviour of An. quadriannulatus was portrayed. Of the
An. gambiae group dissected for parity, 51 .5%) were found parous. This is an
indication that the population was old and was able to maintain transmission
locally despite ongoing vector control measures.
The Global Positioning System (GPS) was used to position larval and adult
mosquito sampling sites. The spatial distribution of adult mosquitoes from the
breeding sites were plotted using GIS soft ware (Map Info ) and the distance
between the breeding sites and study houses were measured using a utility
distance tool. With the aid of GIS, the adult mosquito density in houses could
be used as an indicator to locate the breeding sites in the vicinity. The
importance of these findings in terms of application in cost-effective malaria
control cannot be over-emphasized. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1995.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/10331 |
| Date | January 1995 |
| Creators | Obala, Andrew Ambogo. |
| Contributors | Appleton, Christopher C., Sharp, Brian Leslie., Le Seuer, Dave. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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