Creutzfeldt-Jakob Disease

1. Prion
2. Lesions are characterized by sponge-like changes visible with an ordinary microscope.
3. The agent is highly stable, resisting freezing, drying and heating at normal cooking temperatures, even those used for pasteurization and sterilization.
4. Affects gray matter of brain by deposition of amyloid

A review of the national surveillance data for CJD in Canada between January 1, 1998, and December 31, 2013 was conducted by Coulthart et all (2015). The study included a total of 662 deaths from definite and probable CJD were identified in Canadian residents during the study period, comprising 613 cases of sporadic CJD (92.6%), 43 cases of genetic prion disease (6.5%), 4 cases of iatrogenic CJD (0.6%), and 2 cases of variant CJD disease (0.3%). The overall crude mortality rate for sporadic CJD was 1.18 per million per year [95% confidence interval (CI): 1.08,1.27]. Age-specific rates ranged from 0.05 [95% CI: 0.03,0.08] in persons under 50 years of age to 7.11 [95% CI: 6.20,8.11] in those aged 70 to 79.

Human types:

• sCJD (Sporadic CJD):
  • Is the human prototype of TSE
  • Affects elder individuals (50 to70 years old)
  • Is the most common type
• vCJD (Variant CJD):
  • Affects younger individuals
  • Pose greater risk of iatrogenic transmission
  • Its agent is similar to one that causes BSE in cattle
  • Usually presents with psychiatric illnesses such as depression, anxiety, withdrawal, sensory symptoms such as parastheisa and also cognitive impairment
  • Has longer duration of illness than sCJD
  • PrP gene type 4 is unique to vCJD
• Familial CJD:
  • Accounts for 10-15% of all cases
  • Results from mutation of PrP gene
• Iatrogenic:
  • Introduced accidentally through medical procedure
  • Accounts for less than 1%
  • Person to person transmission through grafts and human growth hormone
• Fatal Familial Insomnia:
  • Is a rare type of inherited human TSE
  • Is associated with PrP gene
• Gerstmann-Straussler-Scheinker disease:
  • Is a rare type of inherited human TSE
  • Is associated with PrP gene
• Kuru:
  • A fatal disease of the CNS
  • Occurred around 1950s in Guinea
  • Presents with cerebellar ataxia, lack of coordination, tremor, rigidity
  • Transmitted through eating brain
  • Not common anymore

Animal types:

• Scrapie: in Sheep and goats
• Chronic wasting disease: in deer and elk
• Transmissible mink Encephalopathy

• Can be transmitted through:
  • Brain and spinal cord
  • Retina and eyes of cattle
  • Vaccines prepared from bovine materials carry the risk of transmission of animal agents
  • Transplantation, surgery, EEG
  • From comparisons with matched controls, procedures involving retina and optic nerve were associated with an increased risk at a latency of ≥1 year OR (95% CI) 5.53 (1.08 to 28.0).
  • At latencies of 10 to 19 years, interventions on peripheral nerves41 (1.17 to 16.6) and skeletal muscle 1.58 (1.01 to 2.48) were directly associated (Neurol Neurosurg Psychiatry)
  • It has also been shown that CJD can be transmitted to humans as a result of treatment with natural human growth hormone. Replacement of natural human growth hormone by recombinant growth hormone has alleviated this risk.
  • Corneal graft
  • Dura matter graft
• No transmission through
  • Milk
  • Milk products
  • Blood (only theoretical risk)
  • Skeletal Meat
  • Never transmitted by direct contact with animals
  • Although there are case reports of CJD among physicians, surgeons, nurses, pathologists, and dentists, there is no epidemiological evidence for occupation risk for health care workers and none of the above cases are confirmed as having been acquired through occupational exposure

1. 30 months to 8 years
2. Can be up to 30 years

1. Human for sCJD
2. Cattle for vCJD

• Progressive dementia
• Clumsiness (cerebellar ataxia)
• Visual deterioration
• Muscle twitching
• Mute
• Death within 5 months

• Clinical diagnosis is the mainstay of diagnosing CJD
• Post-mortem neuropathological examination can be helpful
• Presence of triphasic periodic cpmplexes are often helpful
• No diagnostics available for testing live animals or meat. Post mortem microscopic examination of the brain tissue is being used. Prion can be tested in brain and spinal cord of the dead animals
• CSF test for protein 14-3-3 is very sensitive
• LP is done to exclude other causes of dementia

• Cattle inspection prior to slaughtering
• Animal monitoring
• Product holding
• Prohibiting specific risk materials such as brain and spinal cord of cattle on human foods
• Advanced Meat Recovery (AMR) prohibition
• Air-Injection Stunning Banning
• Prohibiting importation from high risk countries and farms
• Prohibition of meat that is mechanically separated from bone with automatic deboning system
• Prohibition of importation of meat prepared with AMR

• Ask about the history of travel to high risk countries
• History of transplantation
• History of organ donation
• History dietary exposure to brain tissue of animals
• Similar events in other family members