When Anti-Parasitics Meet Wild Hosts: Rethinking Veterinary Treatments in Aquatic Species

This study investigates how veterinary anti-parasitic treatments affect wild European chub (Squalius cephalus) and their naturally occurring acanthocephalan parasites. Using bithionol, a common anthelmintic in aquaculture, researchers observed behavioral changes in fish, including increased opercular movements and altered spatial positioning, while key physiological markers remained unaffected. Surprisingly, acanthocephalan parasites showed no reduction in abundance, size, or reproductive output, suggesting potential resistance or environmental factorsaffecting drug efficacy.