Four Horses Dead, One Ill; Owner Questions
Dewormer
by: Chad Mendell, Staff
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March
2006Article #
6672
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Four horses outside of Hebbronville, Texas, died after they
showed clinical signs of an unknown illness in February; one horse
is recovering. The horses' owner suspects the animals' problems
might have been caused by a dewormer, and she is awaiting necropsy
and other test results. The company that manufactured the dewormer
found nothing unusual about the product lot in question, and it has
notified the Food and Drug Administration (FDA) of the owner's
complaint.
On the morning of Feb. 16, the horses' owner, Kerry (who asked
that her last name be withheld), noticed five of her horses were
acting lethargic, developing fevers, and in some cases were
drooling. She immediately contacted her veterinarian.
"They couldn't eat or drink, though they would try to," Kerry
said. The horse's symptoms progressed over the next 24 hours to
include head pressing, staggering, muscle trembling, sweating,
disorientation (they were bumping into things), and finally lateral
recumbency (they were unable to rise).
"They would then go down and paddle their feet, and their eyes
were glassy looking," she said. "Once they went down like that, they
couldn't get up. They were like that until they died." Four days
after the first clinical signs, four horses had died, but the fifth
showed signs of improvement.
Kerry worried that her other horses might be in danger as well,
so she began investigating her farm for the source of the horses'
illness.
"We tested everything," Kerry said. "We tested the grain, the
water, the weeds in the field; if there's a test for it, we tested
it. They've all come back normal." The necropsy results had not been
released as of March 6.
"The only difference in the horses
that are alive and the ones that are dead is the dewormer," Kerry
said. The day before the five horses became ill, Kerry said she
dewormed them with a generic brand of ivermectin (Bimectin). She
notified Bimeda (www.bimeda.com), the dewormer's
manufacturer, of her suspicion.
Bimeda tested samples from the lot Kerry had used and released a
statement that said, "Upon receipt of a Technical Services review
from the field, (Bimeda) immediately conducted potency testing on
retention samples of Lot 5J019 (the lot in question), and the
results were found to be normal and within the original lot release
potency specifications pursuant to the product's label claim for
active ingredient contents."
Vashti Klein, MA, MBA, a
management analyst for the FDA, said, "We have been in contact with
the company and encourage the owner to report directly to the
company. Veterinarians and animal lovers are encouraged to report
adverse experiences for FDA-approved animal drugs. Pre-testing by
the manufacturer and review of the data by the government does not
guarantee absolute safety and effectiveness due to the inherent
limitation imposed by testing the product on a limited population of
animals."
According to the company, approximately 58,000 doses from the lot
in question have been distributed throughout the United States, with
no other reports of safety or efficacy issues. However, the company
is offering to replace any products from Lot 5J019 with those from
another lot.
Two retailers which offered Bimectin dewormer--Country Supply and
Jeffers--temporarily suspended sales of the product until Bimeda
could test the product. Country Supply posted a statement on its web
site that said, "There is currently a possible safety issue
regarding the use of Bimectin." Both companies resumed sales of the
dewormer after Bimeda released its test results, with the exception
of the lot in question.
Until tests can identify the source of the horses' illness, Kerry
said she's worried about her other horses. "I am paranoid; if one of
them lies down, I go running outside and start taking their
temperatures," Kerry said. "I'm having nightmares about it."
