A 27-year-old white woman from New York City acquired an infection by a Brugia species while she camped in the Amazon basin of Peru. She was infected by at least one adult male worm and one gravid female worm. Both worms were intact and in a lymphatic vessel of a right cervical lymph node. The lymph node and surrounding fibroadipose tissue contained many microfilariae. The male worm was 50 micron wide and the female, 100 micron. Both worms had thin (1 micron) cuticles with fine transverse striations. There were 3 to 4 somatic muscle cells per quadrant. Microfilariae had tails characteristic of the genus Brugia. Although specific identification was not possible from the available material, the worm closely resembled Brugia guyanensis, a parasite of the coatimundi (Nasua nasua) and the only species of Brugia known in South America.