Consequences of polyparasitism on anaemia among primary school children in Zimbabwe.

The effect of concomitant infection with schistosomes, Plasmodium falciparum and soil transmitted helminths (STHs) on anaemia was determined in 609 Zimbabwean primary school children. P. falciparum, haemoglobin levels and serum ferritin were determined from venous blood. Kato Katz, formal ether concentration and urine filtration techniques were used to assess prevalence of Schistosoma mansoni, STHs and Schistosoma haematobium infections. The prevalence of S. haematobium, S. mansoni, P. falciparum, hookworm, Trichuris trichiura and Ascaris lumbricoides were 52.3%, 22.7%, 27.9%, 23.7%, 2.3% and 2.1%, respectively. The overall prevalence of anaemia and iron deficiency anaemia (IDA) were 48.4% (277/572) and 38.1% (181/475). Haemoglobin levels among children who had P. falciparum, S. haematobium and hookworm were lower than negative individuals, p<0.001, p<0.001 and p=0.030, respectively. The prevalence of anaemia and IDA in co-infections was almost double that in single infection. Children with P. falciparum/STHs/schistosome and schistosomes/P. falciparum co-infections recorded higher prevalence of anaemia and IDA (80.8% and 57.4%, respectively) than other combinations, p<0.001. Logistic regression revealed that, age group > or = 14 years, P. falciparum, S. haematobium light and heavy infections, and S. mansoni moderate and heavy infection, hookworm light infection were predictors of anaemia. This study suggests that integrated school based de-worming and malaria control have the potential to reduce the burden of anaemia.