PCR detection of M. musculinus by using the MC28S primer set with fecal samples. Lane 1, 100-bp ladder; lanes 3 through 7, samples containing M. musculinus and D. musculi (group 1); lanes 8 through 12, samples containing M. musculi and R. affinis (group 2); lanes 13 through 17, samples containing M. musculinus and M. musculi (group 3); lane 19, positive control; and lane 20, negative control.