Autogenus vaccines should be backed by data; Skeletal muscle degeneration from monensin.

Chapman: 'You just can't get away from the need for data.'

The merits of autogenous coccidiosis vaccines should not supercede the need for data demonstrating safety, efficacy and quality, according to renowned coccidiosis expert Dr. David H. Chapman of the University of Arkansas.

After he presented a paper at the IX International Coccidiosis Conference in Brazil, Chapman talked with CocciForum to provide additional insights about coccidiosis control.

On the topic of autogenous vaccines, Chapman says, "Just because a vaccine is derived from your own chickens doesn't necessarily mean that it's safe or effective.

"It is theoretically true that a vaccine, unlike most drugs, may be appropriate and effective in one place but not another, and that local requirements need to be considered, which autogenous vaccines do. However, I'm most concerned about quality-related issues."

There are good reasons for the rules and procedures required to make licensed commercial vaccines, and you can't "jump the gun," he says.

"If autogenous vaccines have gone through the same rigorous critique that is applied to licensed commercial vaccines, then I have no problem with them. My concern is that autogenous products usually are not subjected to the same standards, and you just can't get away from the need for data."

The poultry industry, he says, has a right to know that what they're buying is safe and, of course, effective. "And if the data isn't there, they have no way to know. That does the poultry industry a disservice," he adds.

AAP Report links Myopathy to Monensin fed at recommended levels

Skeletal muscle degeneration from monensin, an ionophore antibiotic used to treat coccidiosis in chickens, can occur even when the drug is used at recommended levels, Dr. Scott D. Fitzgerald said in a presentation at the 2005 annual meeting of the American Association of Avian Pathologists.

A number of conditions in chickens have been associated with skeletal muscle degeneration, also known as myopathy. These include vitamin E or selenium deficiency, exertional stress and ionophore antibiotic toxicity, said Fitzgerald, a veterinary pathologist with the Diagnostic Center for Population and Animal Health, Michigan State University.

"We report several cases of ionophore myopathy in chickens associated with the feeding of recommended levels of monensin," he said. Histologic findings were most prominent in the thigh and leg muscles.

The development of myopathy even when monensin was fed at the recommended level was probably due to improper mixing of the feed, interaction with other antibiotics or insufficient antioxidants within the feed, Fitzgerald said.

Lights, camera, chicken!

Coccidiosis specialist Dr. Steve Fitz-Coy (left) leads a mesmerizing wet lab held in conjunction with the IX International Coccidiosis Conference in Brazil last September.

With a camera man standing over his shoulder, Fitz-Coy necropsied chickens challenged with various coccidial organisms while his captivated audience watched on a large screen. For a free DVD of the wet lab, complete and return the reply card that accompanies this issue of CocciForum. Offer limited while supplies last.

Source: CocciForum Issue No.11, Schering-Plough Animal Health.

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