Lab Test For Prions May Yield Diagnostic Tool For TSE Diseases

By Linda McGraw
October 21, 1999

WASHINGTON, Oct. 21--An Agricultural Research Service scientist in Ames, Iowa, has developed a laboratory assay that might lead to the development of a diagnostic test for transmissible spongiform encephalopathies (TSEs).

The laboratory assay, developed by ARS chemist Mary Jo Schmerr, detects the presence of abnormal proteins called prions in the blood of animals and humans. Prions cause a group of TSE diseases.

The most well-known example of these diseases is bovine spongiform encephalopathy or “mad cow disease,” which occurred in Great Britain in 1986. There are no documented cases of BSE in the United States. But all sheep are susceptible to another type of TSE known as scrapie. Elk and mule deer get chronic wasting disease, and mink are susceptible to yet another form of transmissible encephalopathy. Human forms of TSE that affect the brain include Creutzfeldt-Jakob disease and kuru. Creutzfeldt-Jakob disease is rare in the United States, and kuru has never been seen outside New Guinea.

“Further development of this assay may lead to a diagnostic test for this fatal disease agent in animals and humans. Such a diagnostic test would be an important tool for the control of these diseases,” said ARS administrator Floyd Horn.

The presence of BSE in cows has already dealt a severe economic blow to the British beef industry and would have a devastating impact on American agriculture if a case of BSE were identified in the United States.

"Schmerr’s accomplishment is an excellent example of how long-term investment in research can benefit American agriculture," Horn said.

Schmerr, who works at ARS’ National Animal Disease Center in Ames, and Andrew Alpert of PolyLC, Inc. in Columbia, Md., are co-inventors of the assay.

ARS and Fort Dodge Animal Health of Fort Dodge, Iowa, have signed a Cooperative Research and Development Agreement (CRADA) to develop a test kit for use in diagnosing TSEs in animals. ARS--the USDA’s chief scientific agency--is in the process of applying for a patent.

Scientific contact: Mary Jo Schmerr, ARS National Animal Disease Center, P.O. Box 70, Ames, Iowa 50010, phone (515) 663-7287, mschmerr@nadc.ars.usda.go.