Horse Meat Not Tested For West Nile Virus

POSTED: 11:03 a.m. MDT October 13, 2003

GARDNER, Colo. -- None of the millions of pounds of American horse meat headed to U.S. zoos or around the world is tested for West Nile virus, although hundreds of horses have been infected with the virus this year.

Colorado State University researchers say the mosquito-borne disease can be transmitted to at least some animals through their diets but that the virus can be killed through cooking.

At least 2,767 horses were infected with West Nile in 38 states this year, and at least 594 were reported sick in Colorado. The numbers may be low because owners have balked at paying for diagnostic tests.

Each year, 42,000 to 62,000 pounds of American horse meat head to international markets. Four million pounds are processed for domestic use by Central Nebraska Packing in North Platte, Neb., which supplies horse meat to 85 percent of the nation's zoos.

Max Coats, assistant deputy director for animal health programs at Texas Animal Health Commission, said the risk that humans will contract the virus from infected horse meat is low.

"The horse is an accidental host for West Nile. They can't generate enough viremia to infect a mosquito," he said.

Since last spring, however, U.S. Department of Agriculture inspectors have visually examined horses slated for slaughter at Beltex Corp. and Dallas Crown Inc., the two U.S. slaughterhouses that handle horse meat for human consumption.

The veterinarians watch for uncoordinated movements, listlessness, partial paralysis and "downer" horses that arrive for slaughter already dead.

When a horse meets those criteria and is rejected for slaughter, the USDA's Animal and Plant Health Inspection Service is to be alerted. That hasn't yet happened since the directive was issued in April, agency spokesman Steven Cohen said.

But visual inspection runs the risk of missing 9 out of 10 horses infected with West Nile because most show no signs of sickness, CSU biomedical sciences professor Rich Bowen said.

He said parts of the horse -- such as the brain -- can carry enough virus to potentially spread infection.

The USDA nevertheless stands by its practices.

Bowen and other researchers have found that a house cat that eats a mouse infected with West Nile will become infected. Same goes for dogs, raptors and farm-raised alligators.

It's unclear whether all West Nile-tainted meat is equal.

Mice, like horses, carry high West Nile virus loads in their brains, but no one has tested whether animals that eat infected horse meat will become sick.