Helminth infections in slaughtered livestock of Qazvin Province, Iran: implications for food safety and public health.

Helminthic parasites in livestock represent a significant challenge to both animal productivity and public health, particularly in developing countries. This study investigates the prevalence and diversity of helminth parasites in slaughtered livestock in Qazvin Province, north-western Iran an area with limited parasitological data.A total of 6,885 slaughtered livestock including sheep (1,956), goats (1,322), and cattle (3,607) were examined between January 2024 and May 2025. Post-mortem inspections and coprological analyses were performed on major organs, with identification based on morphological and parasitological methods. Seasonal and species-specific patterns were analysed.The overall prevalence of helminth infections was 47.10%, highest in sheep (75.35%) and goats (65.73%), and lowest in cattle (24.50%). Cystic echinococcosis (CE) was the most common cestode, with a prevalence of 11.32%, while Dicrocoelium dendriticum and Fasciola hepatica were the dominant trematodes. Nematodirus spathiger was the most prevalent nematode. Mixed infections were recorded in 9.59% of animals, particularly in sheep. Spring exhibited the highest seasonal prevalence across all host species.The high burden and seasonal variation of helminth infections, especially zoonotic species like CE and F. hepatica, highlight critical food safety and public health risks. Enhanced meat inspection protocols, public education, and integrated control strategies are essential to reduce transmission and safeguard animal and human health in this region.