Smith H J
Can J Comp Med. 1973 Jul;37(3):320-2.
Infecting parasite-free eight week old calves with 8,000 infective Nematodirus helvetianus larvae did not modify appreciably their response to a later heavy field challenge with N. helvetianus, Ostertagia ostertagi and Cooperia oncophora, although two of six animals did have smaller Nematodirus burdens.
用8000条感染性瑞士细颈线虫幼虫感染8周龄无寄生虫的犊牛,尽管6头动物中有2头的细颈线虫负荷量较小,但这并未明显改变它们对后来瑞士细颈线虫、奥氏奥斯特线虫和牛古柏线虫严重野外感染的反应。