US records 7th-ever case of mad cow disease in South Carolina but onward transmission ‘unlikely’

America has detected its seventh-ever case of mad cow disease at a slaughterhouse in South Carolina, health officials say.

The five-year-old cow was diagnosed with the disease at the plant after it was deemed ‘unsuitable’ for slaughter.

The US Department of Agriculture said the animal did not enter the country’s beef supply and officials are not concerned about onward transmission.

The disease, technically termed bovine spongiform encephalopathy, triggers lesions on animal brains giving them a sponge-like appearance and sparking aggression and movement problems. It is always fatal.

Humans who eat meat from contaminated cattle can also catch the disease, which triggers seizures and is fatal in seven to ten patients. Four people in the US have developed the disease to date, all of whom died.

The cow was diagnosed with the disease at a slaughterhouse in South Carolina. Officials say no meat from the animal entered the human supply chain (Pictured: A stock image of a cow with mad cow disease

The case is the seventh ever in the US (US cases in orange) and the first since 2018

Health officials are on high alert for mad cow disease because it nearly always proves fatal to humans.

Millions of cattle had to be put down in the UK during the 1980s and 1990s when they developed the disease after eating feed that contained the crushed meat and bones of cattle that had the illness.

The disease was also detected in France, Germany, Italy and a swathe of other European countries but was not picked up in the United States until 2003, when it was detected in a cow imported from Canada.

Mad cow disease is called by a misfolded protein in the brain — called a prion — that disrupts communication between cells and leads to the symptoms.

Animals can either pick up this protein by eating the meat of others that have the disease, the classic form of the disease, or it can occur spontaneously when a mutation causes the protein to misfold inside them, the atypical form.

It can take years for animals with the atypical form to start to show symptoms. 

The cow in South Carolina was diagnosed with the atypical form of the disease.

It was tested after officials deemed the animal ‘unsuitable’ for slaughter, likely because it was displaying warning signs of the disease.

The animal was also wearing a radio frequency tag that linked it back to a herd in Tennessee.

The US Department of Agriculture, which revealed the case, said: ‘This animal never entered slaughter channels and at no time presented a risk to the food supply or to human health in the United States.’

They did not reveal when the case was detected or whether other animals were now also being tested.

They also did not reveal the fate of the cow, although it is likely that the animal has now been euthanized and the body safely disposed of.

The case marks the seventh ever detected in the United States and the first to be revealed since 2018.

It is also the sixth case of the atypical form of the disease in the US, with only one case of the classical form detected dated back to 2003.

Experts said it was unlikely that the US would face any restrictions to selling cattle in the country or abroad as a result of the diagnosis.

Simon Quilty, an analyst at Global AgriTrends in Colorado, told ABC News that the last time a case was detected in 2018 this led to no trade implications.

‘So you can only assume the same will happen this time around,’ he said.

The biggest countries for beef exports from the US are Japan, South Korea, China and Mexico.

Asked whether China might consider restricting beef trade given the current trade war between the nations, Mr Quilty said this was unlikely.

‘Under the trade agreement between the US and China, they said no ban could be put in place on any atypical BSE case should it occur,’ he added.