The web tool on this page uses Python and Flask to perform the calculations outlined in the paper, estimating the number of shared var genes between two parasite repertoires, based on a limited number of samples from each repertoire. In the blanks below, enter the number of var types found in sampling of parasite A, the number of var types found in sampling of parasite B, and the number found to be shared by both parasites. A credible interval, which measures the uncertainty of the Bayesian posterior estimate, is also calculated and its width (between 0 and 100) can be adjusted.