In contrast to our previous study in PNG among children with clinical malaria, where 30.2% of children with severe anaemia and 12.4% of controls tested positive for B19 IgM, only a small proportion of these Kenyan samples tested were positive for B19 IgM (3.7% of cases and 1.9% of controls). The gene discussed is CD40LG; the disease is anemia (phenotype).