Additionally, nonspecific signs have also been observed which include weight loss, decreased milk production, lameness, ear infections and teeth grinding due to pain.

Once clinical signs arise, they typically get worse over the subsequent weeks and months, eventually leading to recumbency, coma and death.

[3] The outbreak increased throughout the United Kingdom due to the practice of feeding meat-and-bone meal to young calves of dairy cows.

[18] Though any tissue may be involved, the highest risk to humans is believed to be from eating food contaminated with the brain, spinal cord, or digestive tract.

[19][20] Despite the lack of knowledge on potential factors triggering the misfolded protein forms, idiopathic prion disorders are the most prevalent, accounting for 85–90% of human cases.

It has an incubation period of months to years, during which no signs are noticed, though the pathway of converting the normal brain prion protein (PrP) into the toxic, disease-related PrPSc form has started.

At present, no way is known to detect PrPSc reliably except by examining post mortem brain tissue using neuropathological and immunohistochemical methods.

Accumulation of the abnormally folded PrPSc form of PrP is a characteristic of the disease, but it is present at very low levels in easily accessible body fluids such as blood or urine.

After amplifying and then concentrating any PrPSc, the samples are labelled with a fluorescent dye using an antibody for specificity and then finally loaded into a microcapillary tube.

This tube is placed in a specially constructed apparatus so it is totally surrounded by optical fibres to capture all light emitted once the dye is excited using a laser.

The technique allowed detection of PrPSc after many fewer cycles of conversion than others have achieved, substantially reducing the possibility of artifacts, as well as speeding up the assay.

[18][29][30] A ban on feeding meat and bone meal to cattle has resulted in a strong reduction in cases in countries where the disease has been present.

[26] In UK and US slaughterhouses, the brain, spinal cord, trigeminal ganglia, intestines, eyes, and tonsils from cattle are classified as specified risk materials, and must be disposed of appropriately.

To control potential transmission of vCJD within the United States, the FDA had established strict restrictions on individuals' eligibility to donate blood.

[44] In June 2005, John R. Clifford, chief veterinary officer for the United States Department of Agriculture Animal and Plant Health Inspection Service, confirmed a fully domestic case of BSE in Texas.

[48] The US Department of Agriculture (USDA) announced on 19 May 2023 an atypical case of the disease in an older beef cow at a slaughter plant in South Carolina.

[49] US meat producer Creekstone Farms alleged in a lawsuit that the USDA was preventing the company from testing its slaughtered cattle for BSE.

[51] Possibly due to pressure from large agribusiness, the United States has drastically cut back on the number of cows inspected for BSE.

Sixty-five nations implemented full or partial restrictions on importing US beef products because of concerns that US testing lacked sufficient rigor.

In modern industrial cattle-farming, though, various commercial feeds are used, which may contain ingredients including antibiotics, hormones, pesticides, fertilizers, and protein supplements.

[citation needed] For many of the vCJD patients, direct evidence exists that they had consumed tainted beef, and this is assumed to be the mechanism by which all affected individuals contracted it.

[citation needed] Disease incidence also appears to correlate with slaughtering practices that led to the mixture of nervous system tissue with ground meat (mince) and other beef.

[75] During the course of the investigation into the BSE epizootic, an enquiry was also made into the activities of the Department of Health Medicines Control Agency (MCA).

In September, the BSE Working Party of the Committee on the Safety of Medicines (CSM) recommended that "no licensing action is required at present in regard to products produced from bovine material or using prepared bovine brain in nutrient media and sourced from outside the United Kingdom, the Channel Isles and the Republic of Ireland provided that the country of origin is known to be free of BSE, has competent veterinary advisers and is known to practise good animal husbandry".

[77] The Sydney Morning Herald added, "while blustering French politicians blamed Britain for the emergence of the disease – and tried to quarantine the country by banning imports of British beef – they failed to adopt measures to prevent a hidden epidemic at home".

[82] Scottish officials confirmed that the case had been identified as part of routine testing and that the diseased cow had not entered the human food chain.

[85] France continued to impose a ban on British beef illegally long after the European Court of Justice had ordered it to lift its blockade, although it has never paid any fine for doing so.

[77] Russia was proceeding to lift the ban sometime after November 2012 after 16 years; the announcement was made during a visit by the UK's chief veterinary officer Nigel Gibbens.

[92] Publius Flavius Vegetius Renatus recorded cases of a disease with similar characteristics in the fourth and fifth centuries AD.

[93] In more recent UK history, the official BSE inquiry (published 2000) suggested that the outbreak there "probably arose from a single point source in the southwest of England in the 1970s".