COMPARISON OF METHODS FOR RECOVERY OF ASCARIS-SUUM LARVAE FROM TISSUES OF MICE

Experiments were undertaken to compare procedures for isolating Ascari s suum from mice. A standardised intragastric procedure for inoculatio n of A. suum eggs, which had a very low interdose variation (S.D.=6.2% of mean inoculation dose), was developed. There was no significant di fference in the number of larvae recovered from the large intestine 4 h post inoculation (p.i.) by using either Baermannisation of washed in testinal wail or submucosal scrapings. In contrast, a significantly hi gher recovery of larvae was achieved by incubating the intestines vert ically in a cylindrical saline-filled funnel. An agar-gel method was u sed to recover larvae from mucosal scrapings; however, the number of l arvae recovered was the lowest of the methods tried. It was found that a significant increase in larval recovery from the liver at 24 h p.i. resulted when the liver was pressed through a garlic press, rather th an by using homogenisation. For lung recovery, the highest recovery of larvae (at day 8 p.i.) was obtained by disintegration of tissue with a pair of scissors and incorporating the tissue into agar-gel. The met hods presented in this study may be useful for investigation of the hi stology, morphology and molecular biology of the early stages of A. su um. (C) 1997 Australian Society for Parasitology. Published by Elsevie r Science Ltd.