Clayton H M
Vet Clin North Am Equine Pract. 1986 Aug;2(2):313-28. doi: 10.1016/s0749-0739(17)30718-6.
P. equorum is a common and ubiquitous parasite that persists for many years in stables and on pasture in spite of good hygiene and anthelmintic control programs. Foals are usually infected early in life. During the migratory phase of the infection, clinical signs include coughing and a nasal discharge followed by depression and unthriftiness as the worms mature in the gut. Some foals die as a result of intestinal impaction or rupture. Patency is established around 3 months of age, and fecal egg counts may rise to very high levels. From 6 months of age onwards, the ascarid burden diminishes as the foals become immune. Patent infections are seldom found in mature horses and, when present, they tend to be of low magnitude. Preventive measures are aimed at treating foals frequently enough to prevent the development of a large mass of ascarids in the intestine. This is achieved by a 6-weekly dosing regimen using an anthelmintic with proven and reliable efficacy against P. equorum.
马副蛔虫是一种常见且广泛存在的寄生虫，尽管卫生条件良好且实施了驱虫控制计划，但它仍能在马厩和牧场上存活多年。幼驹通常在生命早期就被感染。在感染的迁移阶段，临床症状包括咳嗽和流鼻涕，随后随着蠕虫在肠道内成熟，会出现抑郁和发育不良。一些幼驹会因肠道阻塞或破裂而死亡。大约在3个月大时开始出现排虫，粪便中的虫卵计数可能会升至非常高的水平。从6个月大开始，随着幼驹产生免疫力，蛔虫负担会减轻。成熟马匹很少出现排虫感染，即使出现，感染程度也往往较低。预防措施旨在对幼驹进行足够频繁的治疗，以防止肠道内大量蛔虫的形成。这通过每6周使用一种对马副蛔虫有 proven and reliable efficacy（经证实且可靠疗效）的驱虫药进行给药方案来实现。 （注：“proven and reliable efficacy”直译为“经证实且可靠的疗效”，放在这里语义稍显生硬，但按照要求未作调整）
