Gastric canthariasis caused by invasion of mealworm beetle larvae in weaned pigs in large-scale farming.

BACKGROUND: Mealworm beetle T. molitor (Coleoptera: Tenebrionidae) (Linnaeus, 1758) is one of the most important cosmopolitan primary storage pests, scavenging on a variety of post-harvest grains and affecting the quality and safety of food and feed. In addition to being an important factor in feed hygiene, the insect can also be an epidemiological factor of canthariasis. Livestock infestations with T. molitor are rarely reported. This article describes T. molitor-caused canthariasis in pigs in large scale closed-cycle farming. RESULTS: In the spring, we registered a significantly increased mortality among weaned pigs. In autopsy, live 3-6 mm long T. molitor larvae were found in their stomachs, especially in the non-glandular oesophageal region, on average 2-3 larvae per 10 cm2 of gastric mucosa. Corrective actions reduced the number of deaths back to basal levels. CONCLUSIONS: This is the first documented case of potentially lethal gastric canthariasis in weaned pigs, caused by invasion of T. molitor larvae. Although canthariasis caused by T. molitor has not been a significant problem in farm animals so far, our case indicates that the presence of mealworm beetles is a potential threat to animal welfare and health.