The mean log parasitemia of 11 (AA = 3.68±0.45) genotype and the heterozygote genotype (AC = 3.58±0.41), separately and jointly, differed significantly (P value = 0.001) from that of 22 (CC = 3.40±0.35), while the difference between mean parasite loads representing genotypes 11 and 12 was not statistically significant (P value = 0.153) suggesting a dominant effect of 1 (A) allele over allele 2 (C) for the IL12B+1188 locus to be the most likely explanation. This evidence concerns the gene IL12B and parasitic infectious disease.