Topographical Distribution of Ostertagia spp. in the Abomasum of Sheep

Abstract

A topographical distribution of Ostertagia spp. lesions in the abomasum of sheep has been observed under certain field conditions which is the reverse of that described by Sommerville (1953, 1954) and also seen by this author to be characteristic of a primary Ostertagia spp. infection.This “reverse distribution” has been demonstrated experimentally under conditions in which a heavy primary Ostertagia infection has been acquired (in the field or artificially) and naturally eliminated; the “reverse distribution” is then characteristically acquired by a challenge infection.