Immuno-epidemiology of Schistosoma haematobium infection in Zimbabwean communities with different infection patterns
This study addressed the immuno-epidemiology of Schistosoma haematobium in people living in communities in Zimbabwe with distinct patterns of prevalence and intensity of infection. The studies were located at three different areas within known endemic regions of the country. The two areas located in The Burma Valley were within 10 km of one another. One was designed a Low Transmission (LT) area and the other a High Transmission (HT) area. In these two localities, the immunological studies were centred on the cellular immune responses. Levels of cellular proliferation of peripheral blood mononuclear cells (PBMC) in response to specific (schistosome) antigen stimulation were measured from both school children and adults (age range 5 - 64) in each area, while cytokine production by PBMC was investigated on a smaller cohort of school children aged 7-16 years from each area. T cell clones were derived from PBMC collected from two infected and two uninfected children from the High Transmission area. This aspect of the study attempted to establish if any T helper cell dichotomy existed during human S. haematobium infection by defining the cytokine phenotypes of the clones derived from the PBMC. The longer term aim was to assess the potential predictive value of T cell clones in determining resistance or susceptibility to infection, and thus contribute towards a rationale strategy for vaccine development. The third area of the study was in an endemic region with very high S. haematobium and low S. mansoni infection. This study focused on pre-school children two to six years old and examined the impact of repeated chemotherapy with praziquantel. The children were followed up for 14 months, with praziquantel treatment at each examination point, every eight weeks. The study reports on the antibody isotype profiles in sera collected at each follow-up point during the 14 months of the study.