For MSP-1 responses, differences in prevalence compared to the youngest age class were significant (p value = 0.023) beginning at the third age class (9 to 13 years of age), with those over 20 years of age having 3.7 times the likelihood of previous infection (O.R. – 3.7; 95% CI = 2.48, 5.53). This evidence concerns the gene ATAD1 and infection.