Figure 7. Species determination for human hookworm samples.

(A) Eight human and one canine (A. caninum) sample (+) together with hookworm negative fecal extract (−) were analyzed in duplicate using the ITS-2 primer pair. N. am., Necator americanus; A. du., A. duodenale; M, marker (100 bp ladder, Fermentas). (B, C) Representative PCR products were purified and 150 ng were digested with RsaI and separated using the DNA1000 LabChip® which has a sizing range from 25–1000 bp. Theoretical fragment sizes for N. americanus are 313, 53, 40 and 11 bp and 159, 139, 35, 28, 28, 16 and 12 bp. In silico digestion of A. duodenale or A. caninum fragments leads to identical fragment sizes of 198 and 113 bp. The gel view is shown in (B) for five samples and the electropherogram in (C) for two samples.