[Strongyloides westeri Ihle, 1917 (Nematoda: Strongyloididae). I. Parasitological features of natural infection (author's transl)].

Patent S. westeri infection is particularly common in unweaned foals (61.2 per cent). It is much less common in foals which have been weaned (15.4 per cent). Examination of the faeces of ten artificially reared foals (free from worms) did not supply any evidence of possible prenatal (intra-uterine) helminth infection. In one Shetland pony mare, larvae of S. westeri were found to be present in the milk on the tenth, twenty-fourth and thirty-second day after parturition. Larvae were not detected in the milk of the other mares but all foals showed patent S. westeri infection within from thirteen to sixteen days after parturition. In view of the conditions in which the animals were kept, this can only have been due to galactogenous (trans-mammary) infection.