Mad Cow Disease – correctly known as Bovine Spongiform Encephalitis – hit the headlines some years ago when it was discovered to have infected many cattle in the UK and elsewhere. In its original form it affected cows by slowly destroying their brains. However, it was discovered that by eating infected meat it is possible for humans to contract the disease, and in this form it is known as Variant Creutzfeld-Jacob Disease, or vCJD. This disease has no cure, and is inevitably fatal. Recent changes to the way cattle are fed have led to a decline in cases of vCJD, but as it can take some time to develop it is not certain that there will be no future cases. Here, we describe the mad cow disease symptoms, look in further detail at the causes of mad cow disease and vCJD, and provide a comprehensive FAQ section so that you can fully understand the situation.

Symptoms

Mad cow disease symptoms are associated with the gradual degeneration of the brain. The disease in humans is not the same as that found in cattle – hence the use of vCJD as its proper name – but as in the original form, the brain is slowly destroyed by organisms known as prions. These are similar to bacteria, and appear in many different forms. As the brain degenerates the patient will exhibit some notable symptoms, such as:

  • The onset of dementia and general memory loss
  • Notable personality changes and speech impairment
  • Hallucinations and co-ordination problems
  • Jerky involuntary movements
  • Seizures and balance problems

While many cases of vCJD are caused by having eaten infected beef, others can stem from alternative ways of acquiring the prions into the body. Some cases have come about after blood transfusions or organ transplants. As vCJD can take many years to manifest it is often difficult to spot, particularly as many patients are elderly, but it is important to understand that it is incurable, and that the majority of victims will die within six months of the initial symptoms appearing.

Mad Cow Disease And vCJD Overview

There is a distinction between Mad Cow Disease and variant CJD; the former is the disease as it appears in cattle, the latter as it is in humans. There is an alternative type of the human disease – known simply as CJD – that occurs without any link to infected meat. Still, vCJD is commonly referred to as mad cow disease, even though the two are different.

Both are a form of encephalitis – that is a brain disease in general – and feature the destruction of the brain via the aforementioned prions. It is believed that these can be ingested into the body when eating infected beef. Some years ago a ban on the export of British beef was enforced after thousands of cattle in the UK were found to have been infected; the cattle were destroyed as a result. Although uncommon, vCJD is believed to have killed many people across the world, with some cases having gone unidentified.

Causes

The causes of Mad Cow Disease and vCJD are hotly disputed; as we have said, classic CJD is not related to the bovine form of Mad Cow Disease, yet is often confused with vCJD. If we assume that you can contract the disease from infected meat – as is accepted by many experts in the field – the situation is that the prions in that meat are passed to the human. These then infect the brain, causing the tiny holes that give it the sponge-like look, and begin to destroy the capability of the brain. There is no cure, and there are none likely on the horizon.

Now, let’s covers some frequently asked questions:

FAQ:

Does Cooking Food Kill The Prion That Causes Mad Cow Disease?

In short, no; prions are resistant to heat, and can survive the cooking process.

Does Mad Cow Disease Affect Humans?

The correct answer to this is no; vCJD is the human form of the disease, as explained above. It has similar effects, however.

Is It Possible To Get vCJD From Eating Food Purchased In The U.S.?

Instances of vCJD have been found in the USA, and cattle infected with BSE have been discovered as recently as this year. It remains unlikely, however, as there have been restrictions imposed on the use of certain parts of animals – for example the nervous system – in foods to minimise the risk.

Can You Get vCJD From Drinking Milk From An Infected Cow?

No; there have been no indications that milk can be infected with BSE.

What About Other Products Made From Cow By-Products?

If you eat a burger, for example, that has been made from BSE infected meat you may be liable to contract vCJD, but it remains unlikely. Also, imports of beef by-products from countries where BSE is known to affect cattle have been stopped.

What Is The Risk Of vCJD To Americans Travelling Abroad?

According to officials, very small, though it may pay to be aware in less developed countries where standards are not so rigorously enforced.

How Long Have Health Officials Been Concerned About Mad Dow Disease?

The disease was first noticed in cattle in the UK as long ago as 1986, but the link between BSE and vCJD was not confirmed until 1996.

What Other Countries Have Cases Of Mad Cow Disease?

Apart from the UK and the USA, the following countries have all reported cases in locally born cattle: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Italy, Ireland, Israel, Japan, Liechtenstein, Luxembourg, the Netherlands, Poland, Portugal, Slovakia, Slovenia, Spain and Switzerland.

We hope this guide to Mad Cow Disease and vCJD has allayed some of your fears surrounding this rare but worrying condition, and that we have helped you to understand what it is all about and how it occurs.

Written By John Moorcroft

John Moorcroft, MD, is a highly regarded specialist in Tropical Diseases. Dr Moorcroft studied at the University School of Medicine, gaining a high distinction with a research project in West Nile Disease. His later education included an MD in Pathological Research at the John Hopkins University School of Medicine, in Baltimore.