Blister beetles contain varying levels of a poisonous substance called cantharidin. It is produced by the adult male beetles which is transferred to the females during copulation. Blister beetles consist of over 7,500 species of soft-bodied, long-legged insects from the Meloidae family. They come in a wide variety of colors, sizes, and body shapes.
Blister beetles are found frequently throughout the central and eastern portions of the United States and the West Indies. They feed on floral and leaf parts of a variety of plants, especially those in the families Amaranthaceae, Asteraceae, Leguminosae and Solanaceae. Some commonly cultivated crops from these plant families include potato, tomato, alfalfa, beet, peas, beans, soybean, and chickpeas.
Blister beetles are usually seen eating plants during the day and are attracted to outdoor lights at night. Some species will swarm in large numbers, especially during the flowering stages of plants. Blister beetles are a well-known threat to horses. There have been numerous equine deaths associated consumption of alfalfa hay contaminated with ground up blister beetles.
Clinical Signs of Blister Beetle Poisoning in Chickens
Cantharidin is a potent vesicant and acantholytic agent which causes irritation through direct contact. Once ingested, it damages the bird’s gastrointestinal tract, kidneys, and heart. Endotoxemia can develop secondary to damage to the gastrointestinal mucosa. Clinical signs of blister beetle poisoning in chickens vary considerably and depend on the amount consumed, body size of the bird and health status. However, in many cases the birds are found dead.
Treatment of Blister Beetle Poisoning in Chickens
There is no specific antidote for cantharidin poisoning. Treatment is supportive and aimed at reducing further absorption of the toxin, preventing dehydration, correcting electrolyte and blood gas abnormalities and reduction of pain.