Strongyloides westeri worm and egg counts in naturally infected young horses.

This study investigated the parasite burdens of Strongyloides westeri, a type of threadworm usually found in young foals, in horses older than the usual transmission phase and revealed the influence of age and gender on worm and egg counts. This research showed that despite a decline, S. westeri infections persist even in 6-8 months old foals.

Research Objective and Methodology

• The primary aim was to examine the presence and burden of the S. westeri parasites in horses aged beyond the initial lactogenic transmission phase, which typically sees the highest infection rate in foals up to 4 months old.
• The secondary objective was to understand the influence of the host’s age and gender on the worm burden and the output of eggs in these naturally infected foals.
• In the study, 13 foals were constantly exposed to infections of S. westeri. The health and development of these horses were regularly monitored until the chosen ages for euthanasia (89 to 221 days).
• Post-euthanasia, the worm and egg counts were evaluated. Worm retrieval was carried out using a digestion method that involves evaluating the mucosa of the anterior half of the small intestine. The Mini-FLOTAC method was used to determine the egg counts per gram in their feces.

Results and Findings

• All foals were observed to be healthy with no signs of parasitic disease.
• Despite the assumption that the workload of S. westeri infections normally declines with age, the study found that foals that aged between 4 and 5 months contained significantly higher counts of worm and eggs when compared to those between the age bracket of 6 and 8 months.
• The fecal egg counts were proven to be significantly associated with the worm counts. Despite a notable decline in the egg and worm counts within the 6-8 month age range, the infections were not completely eliminated.
• The persistent presence of infection could either indicate a new infection that was orally or transcutaneously acquired, or the survival of a subset of adult intestinal parasites contracted via the lactogenic route.

Significance of the Study

• This study provided innovative information about the infection patterns of S. westeri in foals aged between 4 to 8 months. By understanding these patterns, researchers and veterinarians can develop more targeted and effective treatments for this parasite.
• Understanding the correlation between worm and egg counts can also provide a more reliable metric for diagnosing and monitoring the progress of the infection.