Probstmayria vivipara pinworms in ponies.

From 1967--1978 observations were made on the presence of the small equine pinworm, Probstmayria vivipara, in seven experimental ponies. The life cycle of this nematode is unusual in that it is endogenous with development of all stages occurring within the host's digestive tract. Initially, worms were found in the feces of four of seven ponies following treatment with thiabendazole but the infection was later transmitted to all ponies possibly via coprophagy. Still later, based on fecal and postmortem examinations, four of the seven ponies lost their pinworm burdens. At necropsy, the principal sites of infection were observed to be the cecum and right ventral colon. Despite the large number of pinworms present, clinical signs were not observed.