Natural superinfection of Parascaris equorum in a stall-confined orphan horse foal.

This research paper studies the occurrence of natural superinfection in a young orphan horse due to Parascaris equorum (a species of parasite), despite it being kept in a parasite-free environment. The researchers investigate the possibility that coprophagy (feed on its feces) allowed repeated infection over a period of time even in a controlled environment.

Overview of the Research Paper

• The research revolves around a single study subject, an orphan horse foal, which was placed in a parasitic-free stall at the age of four days after being born on a pasture.
• Despite the controlled conditions of the stall, the foal was found to be infected by the Parascaris equorum parasite at the time it was euthanized (205 days of age).
• Examination of the infected foal revealed numerous specimens of the parasite, ranging from the infant stage to the adult stage. This indicated that the foal had been infected multiple times over its lifespan.

The Core Inquiry of the Research

• The researchers wondered how this superinfection occurred, investigating the behavior of the foal which was observed frequently engaging in coprophagy – the consumption of its own feces.
• The hypothesis put forth is that the “recycling” of P. equorum eggs due to coprophagy might have allowed for repeated embryonation and reinfection.
• The initial infection of the foal is believed to have occurred from stages it was exposed to on the pasture prior to moving to the stall.

Significance of the Research

• The findings of this paper raise important questions about the management of parasites in controlled environments, particularly related to fouls and their tendency to engage in coprophagy.
• Deeper understanding of this superinfection behavior may dictate revisions of the best practices in the care of horse foals, especially those at increased risk such as orphans.