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Wolf Dog Coalition - June 9 1997 USDA Administrator Medley letter to Congressman Wolf

June 9, 1997

Honorable Frank R. Wolf
U.S. House of Representatives
241 Cannon House Office Building
Washington, D.C. 20515-4610

Dear Congressman Wolf:

Thank you for your letter of May 7, 1997, following up our earlier letter on the labeling of canine rabies vaccines for use in wolves and wolf-hybrids.

Any testing to determine the efficacy of rabies vaccines in wolves and wolf-hybrids must be conducted in accordance whit the Code of Federal Regulations (DFR), Title 9, Section 113.209, which lists the criteria for conducting challenge tests. Per your request, we are enclosing a copy of this section. For the entire reference you may wish to visit our Agency's homepage on the CFR. The address is http://www.aphis.usda.gov/vs/cvb/lpd/9cfrs/9cfrlist.html.

We would like to clarify that a challenge study of a rabies vaccine carried out in accordance with the CFR would not include information about bordetella, coronavirus, or the other diseases mentioned in our earlier letter. Rather, administering modified live virus or avirulent live culture vaccines against these canine diseases could help prove that the immune systems of dogs and wolves contained the same elements in relatively equal ratios, and therefore, that the current canine rabies vaccine would be safe and effective in wolves and hybrids. This would be one option for satisfying the data submission requirement for recommending currently licensed dog vaccines for use in wolves. The other option is conducting challenge studies of rabies vaccines in wolves and wolf-hybrids to a get a recommendation for one specific vaccine for use in wolves.

As we stated in our previous correspondence, the opinion of the experts at the April 1996 meeting concurred that the rabies vaccine currently approved for use in dogs would be effective and potent in wolves and hybrids. Purity was proven in the original studies submitted for dogs. However, the meeting participants expressed a great deal of doubt about the safety of currently approved modified live vaccines for diseases other than rabies in wolves and hybrids. Accordingly, we need to ensure that this vaccine meets the final criteria of the Virus-Serum-Toxin Act, that the vaccines are safe for use in wolves and wolf-hybrids.

Because the similarities between dogs and wolves create a unique situation for our Agency in terms of vaccine approval, we do not have an established standard for the number of animals that should be tested to determine the similarity of their immune systems. While there was some discussion at the April 1996 [should be 97] meeting that 400-800 animals would be sufficient for a study, we have statistically determined that we would need vaccination records from 1,500 animals. In establishing this number we are attempting to strike a balance between an acceptable level of risk and a testing parameter that is attainable.

We would prefer that more than 1,500 animals be tested, and, under different circumstances, we would require many more to be tested; at 1,500 animals, if no adverse reactions are observed, we can have 95 percent confidence that the true reaction rate would not exceed 0.2 percent. However, because we recognize that it may be difficult to locate a large number of wolves and wolf-hybrids, we are willing to accept such a level of risk. To accept any greater level of risk would be contrary to our mission as an Agency and leave significant doubt as to whether dogs and wolves are members of the same species. Per your request, we enclosing our statistical formulations used to arrive at the 1,500 requirement.

We hope this information is helpful.


/s/ Terry L. Medley

Terry L. Medley

cc: Dr. Joan M. Arnoldi, VS, Wash., DC w/cy of inc.
  Mrs. Sally A. Liska, LPA, Riverdale, MD w/cy of inc.

SOURCE: RMiller, JTanner, VS

Copy of original signed letter is available upon request.
Contact The Wolf Dog Coalition ( psykowuf@erols.com ).

Copyright © 1998 Wolf Dog Coalition. All rights reserved. Permission to reprint this letter in its entirety granted.

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