Understand what is ‘mad cow disease’, identified in cattle from MG and MT

The Brazilian government confirmed this Saturday (4) the occurrence of two atypical cases of “mad cow disease” in slaughterhouses in Nova Canaã do Norte (MT) and Belo Horizonte (MG).

The disease is considered atypical when it originates in the bovine’s own body, usually in older animals. Animal samples were sent to a World Organization for Animal Health (OIE) laboratory in Canada for detailed analysis.

These are the fourth and fifth atypical cases recorded in more than 23 years of surveillance for the disease, according to the Agricultural Defense Secretariat of the Ministry of Agriculture, Livestock and Supply (Mapa).

What is mad cow disease?

Bovine Spongiform Encephalopathy, official name of “mad cow disease”, is a degenerative, chronic and fatal disease that affects the Central Nervous System of cattle and buffaloes.

The disease, which has no cure or treatment, causes behavioral changes and can be confused with other diseases that affect the Central Nervous System of animals, such as rabies, intoxication, Babesiosis, among others.

Among the main symptoms of mad cow are:

  • nervousness
  • Seizure
  • Fear
  • teeth grinding
  • Hypersensitivity to sound, touch, light
  • ataxia

It is transmissible to humans, causing a similar disease, the new variant of Creutzfeldt-Jakob Disease (vCJD).

How did mad cow disease come about?

The disease is believed to have emerged in the mid-1980s, when there was an outbreak in the UK, although there is no scientific proof of its origin.

In the late 1990s, some countries in Europe faced an outbreak of mad cow cases because of the consumption, by other animals, of processed feed from cattle affected by the disease.

At the same time, the first cases of vCJD were registered and the first case in the world of probable blood transmission of the variant was confirmed by the United Kingdom and was caused by a blood transfusion by an infected donor who had no symptoms.

According to the Brazilian Ministry of Health, no case of the Creutzfeldt-Jakob variant has been confirmed in Brazil. The injury has already been registered in countries such as the United Kingdom, France, Ireland, Italy, Canada and the United States.

What is the cause of the disease?

It is caused by the infective form of a protein (prion) present in the remains of cattle and buffalo that manifested the disease.

Consumption of prion-contaminated food is the main route of transmission. Healthy animals can contract the disease from eating foods that contain bone meal, meat and carcasses of infected animals.

Therefore, it is prohibited to feed cattle, buffaloes, goats and sheep with products of animal origin.

The Brazilian system of raising cattle, mainly for fattening, is almost entirely on pasture and the food supplement used is based on vegetable protein, such as soy, corn and cottonseed.

What is Brazil doing to prevent contamination?

Since the appearance of the disease in Europe, Brazil’s official animal health defense service has taken measures to prevent the introduction of the disease into the country, such as the ban on importing animals and their products from countries with registration of the disease.

In 1996, the country also banned the use of animal protein in ruminant feed – except for milk and dairy products.

In addition, in 2019, the Ministry created a committee to review regulations for the surveillance, control, eradication, certification and health emergency of mad cow disease.