Background: Malaria co-infection with schistosomiasis is known to modulate the immune response and thereby to potentially alter the pathophysiological and immunological profile of the diseases. The aim of the study was to determine the relationship between subtle morbidities and co-infection with malaria and schistosomiasis, and the immunological responses to the two diseases, among children in rural southwest Nigeria.
Methods: A cross-sectional survey was conducted between April and July 2012 among primary and secondary school children in Eggua, Yewa.North LGA, Ogun State and Omi-Adio, Iddo LGA, Oyo State. A total of 240 children (Yewa 91, Iddo 149) participated in the study. Blood and urine samples were collected from the children and analysed by microscopy for Plasmodium falciparum and Schistosoma haematobium respectively. All the samples were analysed for IL-10, IFN-γ, and some for antibodies to Plasmodium falciparum MSP1(19). Packed cell volume (PCV) and some anthropometric indices (height, weight) were measured as indicator of subtle morbidities of infection with the two parasites.
Results: The prevalence of co-infection with the two parasites in the study was 16%. Malaria prevalence was 35.6% in Eggua, 20.13% in Iddo, and highest in the 11-15 yr age group. Average malaria parasite density was 195.67 parasites/µl blood. Schistosomiasis prevalence was 20.8% in Iddo, 30.8% in Eggua, with highest intensity of infection in age group 11-15 years in both areas. Anaemia was not prevalent among co-infected people (16%). Antibodies to MSP1(19) were found in 36.7%. Peripheral IL-10 levels did not differ significantly among malaria, schistosomiasis, or co- infected individuals, but IFN-γ was higher among older children with schistosomiasis.
Conclusion: Anaemia was not a very discriminating index to indicate morbidity from the diseases in this study area.