As expected, the ZIPCO-ko phenotype recapitulated that of the ZIPCO-F and ZIPCO clones by displaying: normal growth during blood infection, normal mosquito infection capacity generating normal numbers of salivary gland sporozoites, and reduced sporozoite infectivity that can be seen from the 3 day delay in obtaining a parasitemia of 0.1%. The gene discussed is KRT8; the disease is infection.