A multifaceted Schistosoma haematobium study aimed at assessing five different diagnostic techniques of surveillance was conducted. Their use in varying operational circumstances with particular reference to Primary Health Care was conducted in three areas of varying prevalence of disease namely; Mpolweni Mission (44.1%), Empangeni (30.3%) and Verulam (72.0%), KwaZulu-Natal, South Africa. This study incorporated both theoretical and applied components. The theoretical components included freshwater snail surveys, review of literature of S. haematobium diagnostic techniques and an assessment of five diagnostic techniques with particular emphasis on diagnostic performance and cost analyses. Added to these components was migration and the assessment of the prevalence of disease amongst occupants of informal settlements in and around the greater Pietermaritzburg city centre. The applied component included the initiation of a holistic S. haematobium control programme based along the World Health Organisation Guidelines. The study provided insight into several of the countries health issues relevant to both schistosomiasis and other diseases and highlighted weaknesses that may hinder the successful implementation of the current National Framework for Parasite Control. The presence of urban schistosomiasis was noted for the first time in the city of Pietermaritzburg. The present schistosomiasis distribution could be influenced by the rural-urban migration that is impacting upon major metropolitan areas. Without intermediate host snail surveys and schistosomiasis prevalence surveys amongst members of the population, the real geographic distribution of the disease will not be known. The diagnostic methods that were compared included sedimentation, filtration, three brands of chemical urinalysis strips, urine colour scales and an indirect questionnaire. Sensitivity, specificity, positive predictive, negative predictive and efficiency values were determined. Using these values, diagnostic performance ranges were established. The ranges were influenced by the cut-off values used, technique and prevalence and intensity of infection of the study area. The chemical urinalysis strips at cut-off 10erythrocyes/μl (73.7% - 93.2%) were highly sensitive whereas urine colour scales (97.1% - 99.4%) and indirect questionnaire (80.4% - 90.3%) were highly specific. The relationship between the community prevalence rates measured by all five techniques varied significantly. A cost-analysis of the techniques/sample demonstrated a wide price range (20c - R4.32). Therefore their use would be dictated more by the availability of funding than by any operational advantages each individual technique may have demonstrated. Within the public health services a need for: (1) staff training programmes, (2) core staff based within the PHC system that is dedicated to parasite control and (3) a strengthening of infrastructure was demonstrated. These may be achieved via workshops, improved communication, education courses, specific time allocation to parasite programmes i.e. parasite week, project co-ordinators and the designation of tasks. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.

The potential role of sanctuary areas for biological control of Schistosomiasis and development of sustainable fisheries was investigated at Cape Maclear, Lake Malawi National Park (LMNP). There has been a recent increase in the incidence of schistosomiasis infection which is a threat to the local community as well as the tourism industry which is the major source of income to LMNP as well as Chembe Village. At the same place there is increasing fishing pressure due to growing human population and declining fish resource. The increase in the incidence of schistosomiasis transmission was attributed in part to over-fishing of the molluscivorous fish which are believed to control the vector snails for schistosomiasis. Four molluscivorous fish species, Trematocranus placodon; Trematocranus microstoma; Mylochromis sphaerodon and Mylochromis anaphyrmus were reported to account for more than 90% of the fishes (by numerical abundance) which feed on the gastropods above 15 metre depth. The gastropod numbers was reported to be highest at 1.5 to 4.5 metre depth. Of the four molluscivores, T. placodon was proposed as a biological control agent for schistosomiasis based upon the previous observations of its feeding habits in artificial conditions. Captive propagation of T. placodon for reintroduction at Cape Maclear in Lake Malawi has been proposed. The present study aimed at providing baseline data required to test the hypotheses that: 1) Over-fishing of the molluscivorous fish has resulted to the increased incidence of schistosomiasis at Cape Maclear. A sub hypothesis to this was that an extension of the LMNP can act as a sanctuary area for the biological control of schistosomiasis by protecting molluscivorous fish which could control schistosomiasis vector snails. 2) A park initially designed to protect the colourful rock dwelling fish and for promotion of tourism may not effectively protect the food fish. To test the first hypothesis, the biology and ecology of T. placodon were investigated with a view to evaluating the effect this species could have on the schistosomiasis vector snail population and hence the control of bilharzia in the lake. The proportions of various gastropod species at Cape Maclear was compared with those found in T. placodon guts. Comparisons of T. placodon abundance and demographic structure inside and outside LMNP were made. To test the second hypothesis, this study investigated the food fish species that use LMNP 100 m protected zone and some basic ecological factors to appreciate the extent to which the adjacent fishery might benefit from their use of the park waters. T. placodon numerical abundance (number of individuals per unit area) ranged from 5.7 to 40.5 /200 m² and it significantly (P< 0.05) varied between sampling sites. Otter Point and Mitande which are inside the park had the lowest abundance as compared to the other three sites; Nguli inside the park; Fisheries and Nchenga outside the park. Two sites in the park, Otter Point and Mitande, had a greater proportion of mature T. placodon individuals than all other sites. The abundance of T. placodon fluctuated significantly from month to month at Nchenga, Nguli and Fisheries (X² test, P<0.0001 for all the three sites) and insignificantly (P>0.05) at Otter Point and Mitande (X² test). T. placodon densities found in the present study corresponded to the peak density of 30 individuals / 200 m² reported in 1986 but did not correspond to that of 1.0 / 200 m² for 1994. There was no evidence to support the previous reports that T. placodon abundance had decreased tremendously from 1986. The reason suggested to account for the discrepancies of T. placodon abundance reported in the present study and other studies was inadequate sampling in the previous studies which did not take into account spatial and temporal variability in T. placodon abundance. The findings reported in this thesis show that there is no need for captive propagation of T. placodon to be reintroduced into the lake at Cape Maclear and that it may prove to be unsuccessful. However, since juvenile T. placodon dominated in abundance at the three sites along the major beach which is outside the park boundaries, it is suggested that the park boundaries be extended to this area so that T. placodon should be protected to allow individuals to grow to bigger size which would be more effective for gastropod control. T. placodon between 60 mm and 80 mm TL fed on benthic insects, phytoplankton and from detritus material. Individuals between 80 mm and 100 mm fed on a mixture of benthic insects, fish scales and small gastropods and at sizes greater than 100 mm individuals specialized feeding on gastropods. Gastropods of five genera were taken and they were: Melanoides , Bulinus, Gabiella, Lanistes and Bellamya. Of these genera Melanoides fonned the greatest part of T. placodon diet. Bulinus was the second most abundant genus but compared to Melanoides its proportion was very small. Of the three Bulinus species taken by T. placodon, B. globosus, is a confirmed vector for Schistosoma haematobium which is prevalent at Cape Maclear. This species was eaten in the least quantities. A comparison ofthe five gastropod proportions in T. placodon diet and in the habitats they occupy showed that Melanoides were taken in proportionately more quantities than Bulinus at most sites. These findings contrasted the previous reports that T. placodon preferred Bulinus to Melanoides. By applying the optimal foraging theory which predicts that an animal species searching for food will go for the type of prey with the highest profitability, it is concluded that the Bulinus cannot be eliminated completely by molluscivores because if their population size falls below a certain level, the fish will switch to other gastropod types. It is concluded that the increase in schistosomiasis may not be necessarily due to overfishing the molluscivorous fish but could be due to the fact that there has been an increase in the proportion of the B. globosus albeit in small numbers which are infected with schistosomiasis parasites. An integrated approach to schistosomiasis control at Cape Maclear comprising vector control, improved water supply, sanitation and health education is suggested since no method can be effective in isolation. Few food fish species were observed to use the park at various times, varying from one species to another with regards to duration, life history stages and abundance. Only a few fish species taken by the adjacent artisanal and commercial fisheries were represented among those observed in the park. This was attributed to the limited diversity of habitat types covered. Only small population size of some species visited the protected area and only part of the life cycle of some species were observed in the park. The use of the park area was seasonal for some species and the protected zone boundaries can be crossed more than once within a day because 100 m distance is just a few minutes swim by fish. Under such circumstances the park cannot function as an effective sanctuary for food fish. An increase of the park size may be a better option to effectively protect the food fish.