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).

Human prion diseases are not known to spread by social contact, but transmission can occur during invasive medical interventions, exposure to infected human cadaveric-derived pituitary hormones, dural and cornea grafts, and contaminated neurosurgical instruments.

While there is no evidence of occupational transmission of CJD to healthcare workers, it is prudent to be cautious. The highest potential risk is from transcutaneous exposure to high infectivity tissues (CNS) through needle-sticks, puncture wounds, “sharps” injuries, or contamination of broken skin. Exposure by splashing of the mucous membranes (notably the conjunctiva) must also be avoided. Healthcare personnel who work with patients with confirmed or suspected prion disease, or with their tissues, should be appropriately informed about the nature of the hazard and relevant safety procedures.

If you experience a needle-stick or laceration:

1. Wash the affected area with 1N sodium hydroxide solution (household bleach) for 2-3 minutes.
2. Rinse well afterwards with soap and water to neutralize the base.
   • Sodium hydroxide is caustic but relatively slow-acting at room temperature and can be removed from skin or clothing by thorough rinsing with water for 15-30 minutes.
   • DO NOT use sodium hydroxide or bleach in eyes or mouth, or on any other mucous membrane. For a splash to the eye or mucous membrane exposure, rinse well with saline or tap water.
3. Cover wound with waterproof dressing to prevent secondary contamination.
4. Report your exposure.

For detailed guidelines, please read

• UCSF Infection Control Policies and Procedures for Patients with Suspected or Confirmed Human Prion Disease
• WHO Infection Control Guidelines for Transmissible Spongiform Encephalopathies