Prions Agent Information Sheet
Boston University
Research Occupational Health Program (ROHP)
617-358-7647
Agent
Agent
Prion diseases are a variety of neurodegenerative diseases which affect humans, as well as both domestic and wild animal species. In prion diseases, a cellular prion protein (PrPc) normally found in humans is transformed into a pathogenic isoform (PrPSc) upon exposure to a misfolded prion protein. PrPSc is derived from PrPc by a series of posttranslational processes whereby PrPSc acquires a high beta-sheet content. Prions self-propagate and exponentially increase in number, rapidly progressing to kill the host.
Disease/Infection
Five human prion diseases are currently recognized: kuru, Creutzfeldt-Jakob disease (CJD), variant Creutzfeldt-Jakob disease (vCJD), Gerstmann-Straussler-Scheinker syndrome (GSS), and fatal familial insomnia. The following are prion diseases that have been found in animals: scrapie, bovine spongiform encephalopathy (BSE), chronic wasting disease, exotic ungulate encephalopathy, feline spongiform encephalopathy, and transmissible mink encephalopathy.
Pathogenicity
No increased incidence of Creutzfeldt-Jakob disease (CJD) has been found among pathologists who encounter cases of the disease post-mortem. One occupational health exposure reported from France in 2020.
- Special Populations at Risk
Lab personnel working with prions and sharps.
Biosafety Information
Risk Group/BSL
Risk Group 2
Biosafety level: BSL2/ABSL2
Modes of Transmission
Prion diseases are transmissible by inoculation by needle, scalpel or ingestion of infected tissues or homogenates. Infectivity is present at high levels in brain and other central nervous system tissues, and at a slightly lower level in lymphoid tissues, such as the spleen, lymph nodes, gut, bone marrow, and blood. Risk of infection from droplets, and exposure of intact skin is not known. There is no evidence of contact or aerosol transmission of prions from human to another human. There is a case of CJ disease being transmitted to a lab worker 7 years after exposure. There has been no transmission human to human.
| Transmission | |
| Skin Exposure (Needlestick, animal bite, or scratch): | Accidental parenteral inoculation, direct or indirect contact with broken skin |
| Mucous Membrane Exposure Splash to Eye(s), Nose or Mouth: | Unknown |
| Inhalation: | None |
| Ingestion: | Low risk |
Host Range/Reservoir
Prion diseases are found in humans, as well as a variety of domestic and wild animal species, including sheep, goats, cattle, monkeys, chimpanzees, guinea pigs, deer, mice, and cats. The reservoir for prions is the environment and infected animal tissue and carcasses.
Symptoms
Symptoms vary based on the particular pathogen, though are primarily neurological: tremors, ataxia, dementia, muscle weakness, postural instability, behavioral changes, sleep disturbances, and dysautonomia. People with prion disease may also have difficulties in concentration, memory, and judgment.
Incubation Period
15 months to 2 years for CJD iatrogenic cases. 4 to over 20 years for Kuru.
Viability
Prions are resistant to inactivation by normal disinfection processes, including irradiation, boiling, dry heat, and chemicals (formalin, betapropiolactone, alcohols). Animal carcasses and other tissue waste can be disposed by incineration with a minimum secondary temperature of 1000°C (1832°F). The alkaline hydrolysis process, using a pressurized vessel that exposes the carcass or tissues to 1 N NaOH or sodium hypochlorite 20,000 ppm for 1 hour can be used as an alternative to incineration for the disposal of carcasses and tissues. Sterilization of reusable instruments and decontamination of surfaces should be performed in accordance with recommendations described by the CDC (www.cdc.gov) and the WHO infection control guidelines (www.who.int/en/) and BMBL 6th Edition, VIII-H,, Table 4, p.362. These concentrations of disinfectants highly corrosive may cause severe burns to unprotective skin and eyes.
Survival Outside Host
Prion diseases can remain infectious after years in the environment. Studies have reported infectivity of prion diseases up to 16 years after improper decontamination. Contaminated electrodes stored in ethanol-formalin for several years were found to cause CJD in chimpanzees.
Information for Lab Workers
Laboratory PPE
Disposable gowns, gloves (double nitrile gloves), and eye protection must be used when direct contact with infected materials or animals is unavoidable. Eye protection must be used when there is a known or potential risk of exposure to splashes. Extreme care must be taken to avoid accidental autoinoculation or other parenteral inoculations of infectious tissues and fluids.
Containment
BSL-2 practices, containment equipment, and facilities are recommended for activities using clinical materials and diagnostic quantities of infectious material.
In Case of Exposure/Disease
- For injuries in the lab which are major medical emergencies (heart attacks, seizures, etc…):
Medical Campus: call or have a coworker call the Control Center at 617-358–4144.
Charles River Campus: call or have a coworker call campus security at 617-353-2121.
You will be referred to or transported to the appropriate health care location by the emergency response team. - For lab exposures (needle sticks, bite, cut, splash, etc…) involving animals or infectious agents, or for unexplained symptoms or illness call the ROHP 24/7-hour number (1-617-358-ROHP (7647); or, 8-ROHP (7647) if calling from an on-campus location) to be connected with the BU Research Occupational Health Program (ROHP) medical officer. ROHP will refer you to the appropriate health care location.
- Under any of these scenarios, always inform the physician of your work in the laboratory and the agent(s) that you work with.
- Provide the wallet-size agent ID card to the physician.
You will be connected with the BU Research Occupational Health Program (ROHP) medical officer. ROHP will refer you to the appropriate health care location.
Vaccination
No vaccine is currently available.
Information for First Responders/Medical Personnel
Public Health Issues
All evidence of infection due to human prion diseases are reportable to the Massachusetts Department of Public Health (phone: 617-983-6800 and ask for the Epidemiologist On-call). Health care providers should immediately report to the local board of health (BPHC) where the diagnosis was made.
Diagnosis/Surveillance
Monitor for clinical signs. Prion diseases can be diagnosed with neuroimaging, cerebrospinal fluid analysis, electroencephalogram (EEG), and on post-mortem brain biopsy.
First Aid/Post Exposure Prophylaxis
Any skin contact with infectious materials should be followed by washing with sodium hydroxide for 15 minutes. Rinse well. There is no post exposure prophylaxis for prion diseases.
For the following exposures, perform one of the following actions:
| Skin Exposure (Needlestick or scratch): | Immediately go to the sink and thoroughly wash the wound with soap and water for 15 minutes. Decontaminate any exposed skin surfaces with an antiseptic scrub solution. |
| Mucous Membrane Splash to Eye(s), Nose or Mouth: | Exposure should be irrigated vigorously. |
| Splash Affecting Garments: | Remove garments that may have become soiled or contaminated and place them in a double red plastic bag. |
Treatment
No effective treatment has been identified for human prion diseases. Care is mainly supportive. Animal studies suggest that the dye Congo red, anthracyclines, DMSO, glycerol, polyene antibiotics, and copper chelation with penicillamine have shown efficacy in delaying PrPSc accumulation, but none have been tried in human disease.
References
Biosafety in Microbiological and Biomedical Laboratories (BMBL) 6th Edition. Center for Disease Control and Prevention. Last updated June 2020. Section VIII-H: Prion Diseases, p355. Biosafety in Microbiological and Biomedical Laboratories—6th Edition, CDC/NIH/HHS)
Brown, Henry, and John M Lee. “Diseases of the central nervous system caused by prions.” 16 October 2014. UptoDate.com < https://www.uptodate.com/contents/diseases-of-the-central-nervous-system-caused-by-prions>.
Massachusetts Department of Public Health, Bureau of Communicable Disease Control, Guide to Surveillance, Reporting and Control. “List of Diseases Reportable by all Clinical Laboratories.” 13 June 2018.
“Pathogen Safety Data Sheet: Infectious Substances – Creutzfeldt-Jakob agent, Kuru agent.” Public Health Agency of Canada. Last modified 09 July 2015. <https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/creutzfeldt-jakob-agent-kuru-agent.html>.
Saunders, Samuel, et. al. “Prions in the environment: Occurrence, fate, and mitigation.” Prion. 2008 Oct-Dec; 2(4): 162-169. <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658766/>.
Bandel, JP et al. Variant CJ disease diagnosed 7.5 years after occupational exposure. Correspondence, NEJM 383;1, July 2,2020
Revised 6/4/24