Can Creutzfeldt-Jakob disease (CJD) be transmitted to humans through contact with deer and bird feces?

CJD Transmission from Deer and Bird Feces

There is no documented evidence that Creutzfeldt-Jakob disease (CJD) can be transmitted to humans through contact with deer or bird feces. While deer can carry chronic wasting disease (CWD)—a related prion disease—and prions are shed in deer feces, no proven cases of CWD-to-human transmission exist through any route, including fecal contact 1, 2.

Understanding Prion Disease Transmission Routes

CJD Transmission Mechanisms

• Classic CJD transmits only through direct neural tissue exposure, including contaminated neurosurgical instruments, dura mater grafts, corneal transplants, and pituitary extracts 3, 4
• Brain, spinal cord, and posterior eye tissues are highly infectious in sporadic CJD, but other body fluids and excreta are not considered infectious 3
• Variant CJD (vCJD) from bovine spongiform encephalopathy can involve lymphoid tissues (tonsils, appendix), but still requires direct tissue contact for transmission 4

Chronic Wasting Disease in Deer

• CWD prions are shed in deer urine, feces, and saliva, making it highly contagious among cervids with environmental persistence 1
• Despite investigation of three young CJD patients who consumed venison, no causal link was established between CWD and human disease 2
• The molecular characteristics of CWD prions differ substantially from human CJD prions, particularly in glycoform patterns 5

Species Barrier Protection

• Trans-species transmission of CWD appears restricted, with no confirmed human cases despite decades of exposure in endemic areas 1, 2
• Unlike BSE-to-human transmission (which caused vCJD), CWD has not demonstrated zoonotic potential through any exposure route 6, 2
• Molecular analysis shows CWD prion protein differs from human sporadic CJD in critical glycoform ratios and two-dimensional immunoblot patterns 5

Birds and Prion Disease

• Birds are not known reservoirs or carriers of any prion diseases including CJD, BSE, or CWD
• The provided evidence contains no references to avian species involvement in prion disease transmission
• Bird feces pose risks for other zoonotic infections (e.g., Chlamydophila psittaci, influenza) but not prion diseases 4

Practical Risk Assessment

Negligible Risk Scenarios

• Incidental contact with deer or bird feces in outdoor settings poses no documented CJD risk
• Standard hand hygiene with soap and water for at least 20 seconds after animal contact is sufficient for general infection prevention 7

Theoretical Concerns Without Evidence

• While CWD prions persist in the environment through fecal contamination, no mechanism exists for prion transmission through intact skin or casual environmental contact 1
• Prion transmission requires direct inoculation into neural tissue or consumption of infected neural/lymphoid tissue 4, 3

High-Risk Populations Requiring General Precautions

• Children aged <5 years, pregnant women, immunocompromised individuals, and older adults should avoid direct contact with animal feces and environments due to other infectious disease risks (not CJD) 4, 7
• These populations should practice heightened hand hygiene and minimize contact with animal bedding and manure 4

Critical Clinical Pitfall

Do not confuse CWD surveillance concerns with actual human transmission risk. The absence of confirmed human CWD cases after decades of exposure in endemic areas, combined with molecular evidence of species barriers, indicates that casual environmental contact with deer feces does not pose a CJD transmission risk 1, 2, 5.