Humans are unable to develop mad cow disease. However, in rare situations, they may develop a deadly human version of mad cow disease known as variant Creutzfeldt-Jakob disease (vCJD). This can occur if you consume nerve tissue (the brain and spinal cord) from Mad Cow Disease-infected cattle. VCJD is not contagious and cannot be spread from person to person. In addition to nerve tissue, the body also contains other tissues that are used in blood transfusions and transplant operations. These include heart, lung, liver, pancreas, and intestine. It is possible for a person to contract vCJD after having contact with infected material such as blood or bone marrow. In these cases, the vCJD infection would have been passed on even though the patient did not show any signs of being Mad Cow Disease-positive. It is very important to know that just because you do not have Mad Cow Disease does not mean that you are immune to vCJD. Only humans who have had contact with the brain tissue of Mad Cow Disease patients are at risk of getting vCJD. In addition, pregnant women or those who are trying to get pregnant should avoid any kind of meat product that has come into contact with brain tissue from Mad Cow Disease-affected cows. If you are a health professional and suspect that a patient might have vCJD, then it is your responsibility to refer them to a center that can provide them with proper testing.