Mixed strongyle parasite infections vary across host age and space in a population of feral horses.

This research study investigates how mixed strongyle parasite infections, a type of worm, vary across different ages and locations in a population of feral horses on Sable Island, Nova Scotia, Canada. Using advanced DNA techniques, the study findings discover a variety of factors such as age, location, and social groupings influence the different types of infections and their severity in the horse population.

Methodology

• The researchers used DNA metabarcoding on parasite larvae cultured from the faecal samples of 320 feral horses.
• Horse characteristics including age, sex, and reproductive/social status and environmental variables such as location, local density, and social group membership were accounted for to test for their influence.

Findings

• A total of 25 strongyle species were identified in the horses with individual infections ranging from 3 to 18 species with a mean richness of 10.8.
• Young horses were predominantly infected by small strongyle (cyathostomins) species, whereas adults were more commonly infected by large strongyles ( spp.).
• Egg counts, indicative of infection rates, were highest in young horses and in the west or center of the island for most species.

Horse Social Groups and Parasite Communities

• Horses belonging to the same social group displayed similar parasite communities, suggesting that shared environments may contribute to common parasite assemblages.
• Other factors such as the density of horse populations, sex, date and reproductive/social statuses showed minimal impacts on parasitic infection patterns.

Conclusions

• This study indicates that mixed infections in feral horses are dynamic across their lifespan and various geographic areas.
• The research underscores the need to consider species-specific infection patterns when investigating mixed parasitic infections. A one-size-fits-all approach does not apply, highlighting the importance of considering the individual hosts’ characteristics and environment.