Nematode Species Host Species Predilection site Parascaris equorum horses and donkeys small intestine P. equorum is a large white worm, about 40cm long. Under optimum conditions, temperatures of 25 to 35 'C, these eggs will become infective in 10 days or so.
Desiccation is the enemy.
Like Ascaris, the infective stage for Parascaris is the egg containing a second stage larva, L2. The preparasitic phase of the cycle is direct, with no transport hosts. Following ingestion by a suitable susceptible host, eggs hatch and L2's undergo a migration similar to that of Ascaris suum. The prepatent period is 10 weeks. This suggests that foals can be infected soon after birth .