Africanized Bee Swarm Kills Two Horses in California

A California rancher recommends horse owners examine their barns for Africanized honeybee hives after two horses stabled on her Menifee property died subsequent to sustaining hundreds of stings.

Africanized bee

About three-quarters of an inch in length, brownish in color and slightly fuzzy in body texture, Africanized honeybees are nearly identical in appearance to European honeybees.

The two Tennessee Walking horses were stabled in a barn containing undiscovered Africanized bee hives at Wagon Wheel Ranch. On July 21 a ranch hand discovered the animals swarmed by the bees, said ranch owner Christa Caudle Schaffer. A veterinarian called to the scene treated the animals with epinephrine (a hormone that stimulates the sympathetic nervous system to increase heart rate and dilate air passages) and dexamethasone (a steroid anti-inflammatory, immune suppressant drug). Both horses later died of anaphylactic shock, Schaffer said.

Chris Huth, DVM, said anaphylactic shock occurs when horses, humans and other mammals experience a severe reaction to an allergen such as bee venom. The condition causes hives, sweating, difficulty breathing, irregular heartbeat, drop in blood pressure, and fluid accumulation. Severe cases can cause death in horses.

"Bee sting reactions in horses are generally mild," Huth said, "but if you've got 100 or 1,000 bees stinging a horse, it’s likely to go into anaphylactic shock and die."

Africanized bees are an aggressive strain of hybrid honeybees produced by the interbreeding of common European honeybees and African bees that were inadvertently released in Brazil in the 1950s. The insects moved up into Texas, Arizona, New Mexico, and California in the 1990s. Africanized bees establish colonies in barns, vacant buildings, trees, and in ground cavities. Colonies can grow to include as many as several hundred thousand bees. Africanized bees also are known as "killer bees" because they are known to swarm and sting humans or animals that disturb their nests.

About three-quarters of an inch in length, brownish in color and slightly fuzzy in body texture, Africanized honeybees are nearly identical in appearance to European honeybees.

Schaffer said horse owners residing in areas where Africanized bees are located should examine barns, vacant buildings, and other structures for the presence of hives, which are smaller than European honeybee hives and are likely located in cavities such as the walls of older structures, attics or in shallow holes in the ground. Owners who suspect Africanized honeybee infestation should call local beekeepers or experienced exterminators to remove them.

"These bees are very aggressive and can nest just about anywhere," Schaffer said. "The only defense is to be vigilant."

About the Author

Pat Raia

Pat Raia is a veteran journalist who enjoys covering equine welfare, industry, and news. In her spare time, she enjoys riding her Tennessee Walking Horse, Sonny.

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