"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift

September 17, 2010

September 17 - Travassostrongylus sp.

New World opossums are infected by a variety of parasites, including intestinal nematodes from the genus Travassostrongylus. Travassostrongylus encompasses 10 known species and is included in the richest superfamily of parasitic nematodes, Trichostrongyloidea. Using pointed ridges that run along their body, these worms constrict around microvilli in the walls of the intestine and feed on blood. The arrangement of the ridges aids in classification, as do the finger-like structures on the male copulatory bursa, which is a lobular tail that embraces the female during copulation. Species in the genus Travassostrongylus are found in Central and South American opossums. From the semi-aquatic marsupial Chironectes minimus, to the arboreal mouse opossum Marmosa, to the generalist Didelphis, this parasite infects a diverse group of mammals.

Contributed by Phil Scheibel.


  1. If a parasitologist is looking for a host for a lab exercise to demonstrate the variety of helminths, he/she can't go wrong with the Virginia opossum, which is regularly infected with all 4 groups of helminths (cestodes, trematodes, nematodes, acanthcephala). Fresh road kills are readily available. In Florida, they say if you are ever lost in the woods, find a possum and follow it to the nearest road! You will probably not find Travassostrongylus but a couple of other trichostrongylid genera are common.

  2. Can Travassostrongylus sp.infect mud crabs, as well?