Specific analysis of the 2006 MIS data comparing households with ITNs versus households without ITNs showed that after adjusting for other known associations (including child age, urban-rural status, socio-economic status, and use of IRS), children living in houses with ITNs had significant reductions in morbidity in the two year interval: 28% fewer fever episodes in the previous two weeks, 39% lower rates of P. falciparum infection, and 28% less severe anaemia (Hb < 8 gm/dl). This evidence concerns the gene GSTM1 and anemia (phenotype).