Colorado Serum Company will stop production of three equine serum origin products

Due to federal regulations meant to curb the spread of a novel equine virus, Colorado Serum Company said it will no longer produce three products:

  • Novel Equine Serum.
  • Tetanus Antitoxin-concentrated/purified.
  • West Nile Antiserum.

Additionally, the company’s regular Tetanus Antitoxin is required to be labeled “Do not use in equine species,” and Colorado Serum Company said its clients should let customers know. The company will continue producing this product, as well as its Cl. Perf. C&D Antitoxin, for use in other species, “but there may be very limited availability of both products” due to testing requirements, the company said.

As part of its effort to stop the spread of equine parvovirus-hepatitis (EqPV-H), USDA has mandated that all serials of products of equine origin, and all donor animals, be tested for the absence of the virus prior to release for marketing. While the virus only appears to cause disease in horses, donor animals for products that aren’t meant for horses still must be tested.


The company said the testing requirement means it’s not viable to produce the products it’s discontinuing.

Currently, the virus has not been isolated or laboratory-grown, and it can only be detected by a qPCR test. That only measures the presence of genetic material, not live virus.

Colorado Serum Company, as well as the federal Center for Veterinary Biologics and Cornell University, have “been working for several years to develop a test which can detect the presence of live virus, but with no success so far,” according to the company. “Unfortunately, in our opinion, the CVB limit of detection requirement makes the Cornell [qPCR] test overly sensitive and has resulted in, and will continue to result in, the elimination of donor horses and final products that would otherwise be considered acceptable.”

Based on qPCR testing, “there is a high prevalence of [equine parvovirus-hepatitis] genetic material in the healthy horse population which will make finding negative donor horses very difficult going forward,” the company said.