Epidemiology of schistosomiasis in Gezira area Central Sudan and analysis of cytokine profiles

Abstract

OBJECTIVE: To determine and compare anti-schistosoma IgG, interleukin-10 (IL-10) and interferon-γ(IFN-γ) levels in the serum of patients and endemic controls and to investigate the epidemiological situation of Al-Hebaika village in the northern part of Gezira Agricultural Irrigation Scheme in 2005. METHODS: During 2005 survey, serum were collected from 118 villagers. Sixty eight were parasitological positive (patients), and 50 were negative (endemic controls). Indirect ELISA was used to measure and compare the levels of immunoglobulin G (IgG) against Schistsoma mansoni (S. mansoni) soluble worm antigen (SWA) in the patients and endemic control groups from the village and compared with 20 healthy non endemic controls. Sandwich ELISA was also used to measure and compare IL-10 and IFN-γ in the serum of the selected groups. RESULTS: The overall prevalence of S. haematobium was 20.0% and 0.9% in the first and the second surveys respectively, while the intensity of infection was the same in the two surveys 1.38 [geometric mean egg count (GMFC)]. The overall prevalence of S. mansoni infection was 68.5% and 15.4%, while the intensity of infection was 2.75 (GMEC) and 1.70 (GMEC) in the two surveys respectively. IgG reactivity against SWA showed no significant difference between Schistosoma positive patients and endemic controls. However, there were high significant differences between each of these two groups and the non endemic control group (P= 0,000). Schistosoma patients and exposed controls had significantly higher IL-10 concentration compared with non endemic controls. While endemic controls showed significantly higher IFN-γ concentration than patients (P = 0.000). Also there was very significant difference between IFN-γ levels of each of patients endemic controls and that of the non endemic controls (P = 0.003). CONCLUSIONS: The study concluded that IFN-γ has a role in the natural resistant to schistosoma mansoni infection. The prevalence and intensity of S. mansoni in the Gezira Irrigation Scheme was greatly reduced. S. haematobium has disappeared from the area.