Short report: a new case report of human Mesocestoides infection in the United States.

The twenty-seventh documented case of human Mesocestoides infection, which corresponds to the seventh documented case in the United States, is reported. The case had its origin in Alexandria, Louisiana in the summer of 1998. The patient was a 19-month-old boy. The strobila consisted of 35 proglottids that included mature as well as gravid segments containing a ventral genital pore and a parauterine organ. After a detailed microscopic examination, the tapeworm was identified as belonging to the genus Mesocestoides. Mesocestoides variabilis is the probable species responsible for the infection, since the six cases previously reported in the United States were identified as this species. After the treatment with a single dose of praziquantel (10 mg/kg), the tapeworm segments were no longer detectable in the child's feces. A food-borne origin of this infection derived from culinary customs of the Acadian and Creole communities in Louisiana is proposed.