Jeffcoate I A, Wedrychowicz H, Fishwick G, Dunlop E M, Duncan J L, Holmes P H
Department of Veterinary Physiology, University of Glasgow Veterinary School.
Res Vet Sci. 1992 Sep;53(2):212-8. doi: 10.1016/0034-5288(92)90112-f.
The relationship between anti-parasite IgA antibody levels in plasma and the periparturient egg rise in sheep was investigated. Ostertagia circumcincta larvae (5000 third stage larvae three times weekly) were administered to three groups of seven adult immune ewes from 12 weeks before until three weeks after lambing (group 1) or from six (group 2) or 14 (group 3) weeks before until three weeks before lambing. Seven additional ewes were not challenged (group 4 controls). Ewes in groups 1, 2 and 4 received anthelmintics 14 weeks before lambing. Challenge of the pregnant ewes with O circumcincta larvae resulted in substantial increases in faecal egg counts only during the periparturient period regardless of the larval dosing regimen. Furthermore, the periparturient rise in faecal egg counts was closely associated with a significant increase in anti-parasite IgA antibody levels in plasma. This rise in IgA antibody levels occurred at a time when IgA is transported from the gut to milk during early lactation. It is postulated that this may lead to a temporary reduction in abomasal antibody levels of ewes and hence permit the establishment of larvae and, or, the emergence and development of inhibited larvae and thereby lead to the periparturient rise in faecal egg count.
研究了绵羊血浆中抗寄生虫IgA抗体水平与围产期虫卵数增加之间的关系。从产羔前12周直到产羔后3周，每周3次给三组7只成年免疫母羊接种5000条环纹奥斯特线虫第三期幼虫（第1组）；或从产羔前6周（第2组）或14周（第3组）直到产羔前3周接种。另外7只母羊不进行攻虫（第4组为对照组）。第1、2和4组的母羊在产羔前14周接受驱虫药。无论幼虫给药方案如何，用环纹奥斯特线虫幼虫对怀孕母羊进行攻虫仅在围产期导致粪便虫卵数大幅增加。此外，围产期粪便虫卵数的增加与血浆中抗寄生虫IgA抗体水平的显著升高密切相关。IgA抗体水平的这种升高发生在泌乳早期IgA从肠道转运到乳汁的时候。据推测，这可能导致母羊皱胃抗体水平暂时降低，从而使幼虫得以建立，和/或使受抑制的幼虫出现并发育，进而导致围产期粪便虫卵数增加。
