West Nile Virus Treatment: Plasma Product Licensed

On Oct. 23, Lake Immunogenics became the first company to receive a USDA conditional license for West Nile virus (WNV) Antibody, Equine Origin, as a plasma product. The product already was a USDA-licensed plasma product under the name HiGamm-Equi, and was used off-label to treat WNV infection before it was licensed for this use.


West Nile Virus Antibody, Equine Origin, the first conditionally licensed plasma product for treating West Nile virus.

Plasma products traditionally have been used for failure of passive transfer, to prevent Rhodococcus equi infection in foals, and to treat botulism in horses of all ages. Lake Immunogenics' equine plasma donors are vaccinated against a variety of diseases so that antibodies get passed on to the plasma recipient. Since December 2001, the donors have been vaccinated multiple times with the WNV vaccine. The company had to prove purity, safety, and reasonable expectation of efficacy to have the plasma conditionally licensed for treating WNV.

A WNV equine antiserum treatment produced by Novartis Animal Vaccines received a USDA conditional license in August 2003 (see article #2694).

Both plasma and antiserum products raise antibodies a targeted specific disease such as WNV; the difference is that serum products have had clotting factors removed while plasma products still have them.

The WNV serum product comes in a vial and is diluted before being administered intravenously; the hyperimmune plasma product comes frozen in a bag that is ready for intravenous administration immediately after thawing.

James L. Bowman, DVM, president of Lake Immunogenics, said that adult horses given the plasma develop an effective WNV antibody titer. An unpublished Colorado State study of hamsters determined that the product eliminated WNV in the bloodstream when given before or after WNV challenge.

As with any USDA-licensed product, each serial manufactured must match or exceed what was used in efficacy studies. "There's a level of consistency and reliability with a licensed product that unlicensed products aren't required to achieve," he explained.

Bowman plans to proceed toward attaining a full USDA licensure for Lake Immunogenics' WNV Antibody as soon as possible.

About the Author

Stephanie L. Church, Editor-in-Chief

Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.

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