The CNS tissues, specifically brain, dura mater, spinal cord and eye are highly infectious. In vCJD, lymphoreticular tissues are also highly infectious. Cerebrospinal fluid (CSF) and several organs outside the CNS (lung, liver, kidney, spleen and placenta) are considered less infectious but should still be treated with caution.

Only vCJD has been shown to be transmissible by blood transfusion from human to human. Although transmission from blood in other human prion diseases (not vCJD) has not been shown, there is a theoretical risk; therefore, any exposure with confirmed or suspected prion disease (or with a relative with CJD) must be considered exposure to prion disease.

It is not clear how cautious one needs to be in performing non-neurosurgical invasive procedures on patients with prion disease. Most medical centers treat such procedures and equipment with universal precautions. At our center, due to the high number of patients seen with prion disease, we are more cautious with invasive medical procedures.

When working or caring for patients with prion disease, casual and even intimate contact is not considered a risk factor. When dealing with bodily fluids and excretions, such as blood, urine or feces, we recommend universal precautions (disposable gloves and disposing of material that comes in contact with such fluids).