Horse Fly Strike: Maggot Infestation in Equines

Fly strike, or myiasis, occurs when flies lay eggs on horses and the hatching maggots burrow into living tissue, causing severe pain, tissue destruction, and potentially fatal systemic infection.

Key Facts

Blowflies including Lucilia and Calliphora species are the primary causes of myiasis in horses
Fly strike typically begins in wounds, areas of skin moisture, or soiled coat around the hindquarters
Maggots can consume large amounts of living tissue within 24-48 hours if left untreated
Horses with wounds, skin conditions, or poor hygiene management are at highest risk
The process releases toxins that can cause systemic illness and death in severe cases
Fly strike is most common in summer months when fly populations peak
Prevention includes wound management, regular grooming, fly control products, and environmental hygiene

Welfare Considerations

Fly strike causes intense suffering. The initial sensation of flies landing and laying eggs is irritating; the subsequent maggot activity causes escalating pain as larvae burrow through tissue, releasing enzymes that liquefy flesh. Affected horses show extreme distress, stamping, biting at affected areas, and in severe cases, shock. The process can be rapid - an overlooked wound can become severely infested within a day during fly season. The combination of physical destruction of tissue, pain from toxin release, and secondary infection creates a welfare emergency requiring immediate veterinary intervention.

What You Can Do

Inspect horses daily for wounds, particularly during warm months when fly activity is highest
Implement comprehensive fly control including traps, repellents, and barrier products
Manage wounds promptly and keep dressings clean and dry to prevent fly attraction
Maintain clean stabling and remove manure regularly to reduce fly breeding sites
Seek veterinary care immediately if any maggot infestation is discovered