Improved method for the recovery of Ascarus suum larvae from pig intestinal mucosa

In the course of a comprehensive study on the population biology of Ascaris suum, it became necessary to determine quantitatively the migration of the larvae (L2) through the pig intestine. Because no satisfactory methods for recovering these larvae from the intestinal mucosa were apparently available in the literature, we undertook the development of such a procedure. Direct Baermannization of the intestine proved inadequate, so a series of studies was undertaken to find a method to solubilize the mucosa and free the larvae. Both pepsin digestion and mucus reduction with N-acetyl cysteine were evaluated. The highest recovery rates were obtained with short-term pepsin digestion (45-90 min), followed by a specific settling and washing procedure. A third alternative, migration of larvae out of agar-gel, was also tested. Although the recovery efficiency was low (10% of pepsin digestion), the larvae recovered were clean, with good motility. The agar-gel procedure could be useful when L2 larvae are needed for other purposes, such as antigen preparation or cultivation.