CDKN2A and giardiasis: The relative expression of the CDKN2A gene in samples with a history of giardiasis A2 and A4 increased by 4.56 and 2.99 times, respectively, compared to the average expression of the CDKN2A gene in healthy individuals, and the expression of the gene in sample A8 was almost equal to the standard (p > 0.05).