Alabama's mad cow had 'atypical' form of disease

An 11-year-old cow was identified in Alabama with the neurological condition known as 'mad cow disease.' The discovery was made before the cow was butchered and, according to the USDA, wasn't at any point any sort of risk for the food supply chains. The discovery of the disease was first made during a routine surveillance of the cows; this particular victim was said to be presenting clinical signs of mad cow disease upon discovery.

Mad cow is the term used to describe Bovine Spongiform Encephalopathy, a disease that manifest in two different ways: 'classic' or 'atypical.' Analysis has found that this particular cow had the 'atypical' form of the disease, which is believed to arise spontaneously in cattle, and generally only in ones that are of an advanced age (that is, greater than 8 years old).

This is in contrast with so-called classic mad cow disease, which is thought to result from feeding cattle grains that are infected with a prion agent. The neurological disease has arisen in cattle populations in the past, such as in the UK in the 1980s, and in scattered few cases in the US over the years.

At one point, the discovery of a mad cow in the US triggered a US beef import ban in many countries. However, only one instance of classic-type mad cow has been made within the US, and that was via beef imported from Canada. In the other four instances of mad cows, all of them have been atypical cases.

As it stands, researchers are investigating the latest instance. The USDA says this latest case, due to the fact that it involves atypical mad cow disease, will not harm the US's 'negligible risk' rating by the World Organization for Animal Health. The US took steps to minimize classic mad cow disease risk in the late 90s by barring the use of mammalian protein in cattle feed, and it later bolstered that measure in 2009 by banning the use of high-risk tissues in any and all animal feeds.