Differentiation between the Human Hookworms Ancylostoma duodenale and Necator americanus Using PCR-RFLP

Abstract

There are 2 major species of hookworms that infect humans. Ancylostoma duodenale and Necator americanus. Although traditionally considered to be identical for treatment purposes, there are significant life history differences between the species that must be considered for the rational design of chemotherapeutic and immunoprophylactic control strategies. However, identification of the species infecting a particular population has been problematic, as the eggs of the 2 species cannot be reliably differentiated by classical parasitological methods. A PCR-based technique for the differentiation of hookworm species that infect humans is reported. A fragment of the 3' untranslated region of the cAMP-dependent protein kinase catalytic subunit gene was amplified from A. duodenale and N. americanus genomic DNA using primers derived from the corresponding A. caninum cDNA. Digestion of the amplified DNA with the restriction enzymes HpaII, MboI, TaqI, and ThaI generated specific restriction fragment patterns unique to each species. The technique can distinguish between pure and mixtures of hookworm DNA and can amplify DNA from a single egg. The primers also amplify the fragment from the DNA of several other species of hookworms that infect humans and other animals. The technique is fast, simple, and hookworm specific and represents a considerable savings in time over current methods used for distinguishing between human hookworm infections.