Genetic aspects of host resistance to helminthic infections

Abstract

The utilization of within-breed individual genetic variation of the responsiveness of host animals offers a new strategy between the innate responsiveness of hosts and worm establishment. This overview gives a brief account of the results obtained in rodent-parasite laboratory models and in sheep infected by gastrointestinal nematodes. for high (HR) and low responder (LR) discrimination, direct criteria (worm counts, faecal egg counts) are being used and indirect criteria (lymphocyte antigens, etc.) are being sought. Results concerning the heritability of innate resistance, the specificity, the economic and epidemiologic consequences of selection for parasite resistance, and the possibility of the adaptation of the parasite to the more resistant hosts are also discussed. Currently available evidence provides a sense of optimism that genetic resources can be exploited in the control of parasitic gastroenterlitis.