Study of the ethiological agent of gnathostomosis in Nayarit, Mexico.

In order to clarify the specific identity of the etiological agent of human gnathostomosis in Nayarit State, Mexico, morphological and molecular studies were conducted on advanced third stage larvae obtained from human and fish tissue. Cathorops fuerthii from Agua Brava lagoons complex, was the only fish species found to be infected among four species surveyed. Morphological variability does not allow specific identification of the larvae. Internal transcribed spacer 2 of the ribosomal DNA was sequenced for six larvae (five from fish, one from human tissue). Low divergence in the sequences of Nayarit larvae and Gnathostoma binucleatum (0.24% or less) indicate that the larvae examined belong to this species.