Ashish A. Deshpande

Spongiform = Sponge like Encephalopathy= Brain Disease [encephalon + pathy= the technical name of brain + Pathy = disease]

Disease name Natural host Prion name PrP isoform

Non-human mammals

Scrapie Sheep and goats Scrapie prion OvPrPSc

Transmissible mink encephalopathy (TME) Mink TME prion MkPrPSc

Chronic wasting disease (CWD) Elk, White-tailed deer, Mule Deer and Red Deer

CWD prion MDePrPSc

Bovine spongiform encephalopathy (BSE) commonly known as "Mad Cow Disease"

Cattle BSE prion BovPrPSc

Feline spongiform encephalopathy (FSE) Cats FSE prion FePrPSc

Exotic ungulate encephalopathy (EUE) Nyala and greater kudu

EUE prion NyaPrPSc

Human diseases

Kuru

Humans

Kuru prion

HuPrPSc

Creutzfeldt-Jakob disease (CJD) CJD prion

(New) Variant Creutzfeldt-Jakob disease (vCJD, nvCJD)

vCJD prion

Gerstmann-Sträussler-Scheinker syndrome (GSS)

GSS prion

Fatal familial insomnia (FFI) FFI prion

Known Spongiform Encephalopathies

In general, it is a disease. A group of rare degenerative brain disorders characterized by tiny holes that give the brain a "spongy" appearance. Occurs in Humans and Vertebrate animals (Vertebrate = Animals having backbone) TSE = A disease capable of being transmitted by infection and gives the appearance of sponge like tiny holes in the brain. There are many types of Human TSEs. The literal meaning of TSE is as below Transmissible = Capable of being transmitted by infection Spongiform = Sponge like Encephalopathy= Brain Disease [encephalon + pathy= the technical name of brain + Pathy = disease]

TSE - Transmissible Spongiform Encephalopathy ?

It is a brain disease that occurs in bovines; generally known as “Mad Cow Disease” BSE = A disease capable of transmitted by infection and gives a appearance of sponge like tiny holes in the brain of bovines. The literal meaning of BSE is as below Bovine = Characteristic of or resembling cows or cattle. Spongiform = Sponge like Encephalopathy= Brain Disease [encephalon + pathy= the technical name of brain + Pathy= disease]

BSE - Bovine Spongiform Encephalopathy ?

Prion

• Smaller than smallest known virus

• Not yet completely characterized

• Most widely accepted theory

– Prion = Proteinaceous infectious particle

• Normal Protein

– PrPC (C for cellular)

– Glycoprotein normally found at cell surface inserted in plasma membrane

Normal protein

• Secondary structure dominated by alpha helices

• Easily soluble

• Easily digested by proteases

• Encoded by PRNP gene (in humans)

– Located on human chromosome 20

Abnormal Protein

• PrPSc (Sc for scrapie)

– Same amino acid sequence and primary structure as normal protein

– Secondary structure dominated by beta conformation

• When PrPSc contacts PrPC

– Converts it to the abnormal form

Abnormal Protein

• Insoluble in all but strongest solvents

• Highly resistant to digestion by proteases

– Survives in tissues post-mortem

• Extremely resistant

– Heat, normal sterilization processes, sunlight

• No detectable immune response

o No antibiotics can cure disease caused by prions

o They are not typical of a prokaryotic organism or a eukaryotic organism

o All that is present in this pathogen is the protein PrPSc, the mutation of PrPC

o PrPSc is resistant to any form of digestion

o Prions are non immunogens and do not induce an immune response

o Prions are not easy to decompose biologically

o They are resistant to high temperatures & disinfectants

Center for Food Security and Public Health Iowa State University - 2004

Kuru

• New Guinea in early 1900’s

– People practicing cannibalism

– 1957-1968

• Over 1,100 people died

– Majority of deaths

• Women, children and elderly

– Incubation period >30 days

Creutzfeldt-Jakob disease (CJD)

• Sporadic (Scattered) human encephalopathy

• Worldwide 1-2 cases/million people

• Different forms

– Spontaneous (85%)

– Genetic (10-15%)

– Iatrogenic/ consequence of medical treatment (<1%)

• Average age of onset 65 years

• Duration of illness, 4.5 months

Bovine Spongiform Encephalopathy

• 1986, First confirmed case in United Kingdom (UK)

• 1988, UK bans meat and bone meal from ruminants in cattle feed

• 1989, USDA bans importation of ruminants from countries with BSE

• 1993, Peak of BSE in UK

– 1,000 new cases reported weekly

• 1997, US & Canada ban ruminant products fed back to ruminants

– US importation ban extended to all of Europe

• 2001, European Union ordered mandatory tests on cattle

– Older than 30 months destined for slaughter

• May 2003, BSE diagnosed in 6 yr. old Angus beef cow in Alberta, Canada

– Herd mates all tested negative

– Single case in 1993 was cow imported from UK

• December 2003, BSE diagnosed in 6½ yr old Holstein cow in Washington State

– Possibly imported from Canada

• DNA testing being conducted

– Complications following calving

– Sent to slaughter

– Brain tissue sent to NVSL–per FSIS protocol

• Presumptive positive by NVSL

– Definitively positive by UK lab

vCJD • Variant Creutzfeldt-Jakob disease (vCJD) is a rare and fatal

human neurodegenerative condition.

• The consumption of food of bovine origin contaminated with the agent of Bovine Spongiform Encephalopathy (BSE), a disease of cattle, has been strongly linked to the occurrence of vCJD in humans.

• 1995, UK: First confirmed case

• Incubation period not known

• Mean age at death- 28 years old

• Mean duration of infection : 1- 4 Months

• 175 cases of vCJD were reported in the UK , and 49 cases in other countries from October 1996 to March 2011.

• Following the successful containment of the BSE epidemic in cattle, the number of cases of vCJD in the United Kingdom has declined since 2000.

Characteristic Classic CJD Variant CJD

Median age at death 68 years 28 years

Median duration of illness 4–5 months 13–14 months

Clinical signs and symptoms Dementia; early neurologic signs

Prominent psychiatric/behavioral symptoms; painful dysesthesias; delayed neurologic signs

Periodic sharp waves on electroencephalogram

Often present Often absent

Signal hyper intensity in the caudate nucleus and putamen on diffusion-weighted and FLAIR MRI

Often present Often absent

Pulvinar sign-bilateral high signal intensities on axial fluid attenuated inversion recovery (FLAIR) MRI. Also posterior thalami involvement on sagittal T2 sequences

Not reported Present in >75% of cases

Immunohistochemical analysis of brain tissue

Variable accumulation. Marked accumulation of protease-resistant prion protein

Presence of agent in lymphoid tissue Not readily detected Readily detected

Increased glycoform ratio on immunoblot analysis of protease-resistant prion protein

Not reported Marked accumulation of protease-resistant prion protein

Presence of amyloid plaques in brain tissue

May be present May be present

Clinical and Pathologic Characteristics:

Transmission

Human Transmission

• Humans consuming cattle products infected with BSE can develop vCJD – Brain and spinal tissue

• Dose required not known • Genetic susceptibility

– All human cases have been homozygous for methionine at codon 129 of PrPC

• Possible modes

– Transmission from surgical instruments used on tonsils, appendix, or brain tissue

– Growth hormone injections

– Vaccines

Human Transmission

• Unlikely modes

– Blood transmission

– Consumption of milk and milk products

– Gelatin products (when manufacturing process is done correctly)

Transmission: Animals • BSE

– Cattle feed • Sheep carcasses infected with scrapie • Cattle carcasses infected with unknown TSE

– Maternal transmission occurs at very low levels • Scrapie

– Spread from ewe to offspring through placenta and placental fluids

– Genetic susceptibilities

• FSE and exotic zoo animal forms – Feed contaminated with BSE infected cattle products

• CWD: Environmental, other? • TME: Not known at this time • Number of animals infected experimentally

– Hamsters, mice, rats, voles, gerbils, some species of monkeys

Diagnosis: vCJD

• U.K. criteria for antemortem diagnosis – Neuropsychiatric disorder with duration longer than 6 months – Specific clinical signs – Abnormal EEG – Tonsilar biopsy with detectionof prion protein

• Post mortem definitive diagnosis – Amyloid plaques surrounded by vacuoles – Prion protein accumulation in cerebellum – Spongiform appearance in gray matter

Treatment: vCJD

• No effective treatment available

– Experimental drugs under investigation

• Quinicrine

• Symptomatic treatment

• Supportive care

Incubation Period

• Scrapie: Sheep 2-5 years

• BSE: Cattle 2-8 years

• CWD: Deer and elk 18 months

• TME: Mink 7+ months

• FSE: Feline unknown, most 4-9 years of age

There is a possible risk of contamination of infected animal derived products in the pharmaceutical finished dosage form for human consumption leads to transmission of TSE/BSE to human beings.

In some cases, the Pharmaceutical preparations like Finished Dosage Forms, Active Pharmaceutical Ingredients and their Starting Materials, and Primary Packaging Materials involves the use of products/materials derived from animals. For example, use of proteins, enzymes, amino acids from animals used in the manufacturing of API and API starting materials.

The primary packaging materials like gelatins capsules derived from the fat of animals also increases the possibilities of transmission of TSE/BSE.

Risk in Pharmaceuticals

There is a high risk in the case of biotechnological products like serums, blood products and vaccines where the source material is derived from animals and animal derived products

There is also a possible risk of TSE/BSE through the equipments/utilities where in biologically-derived products and/or products of animal origin is handled. For example, Culture media used in reactors for media fill studies.

Ideally, the use of such animal derived product/material should be avoided in the pharmaceutical preparation. However, during unavoidable circumstances, the use of such animal derived products is accepted, provided that the manufacturing process and procedures complies to the applicable regulations set by WHO, European Commission and USFDA

Risk in Pharmaceuticals

U.S. Government Precautions

• 1989: Import restrictions

– Live ruminants and ruminant products

– From countries known to have BSE

• 1997

– Import restrictions expanded to include all European countries

– FDA “animal feed rule”

• Banned most mammalian proteins as food source for ruminants

U.S. Government Precautions

• Targeted surveillance – High risk animals

• Adult animals with neurological signs • Non-ambulatory “downer” cows • Rabies- negative cattle • Cattle dying on farms

– 2003: 20,000 animals tested for BSE • 47 times the number required by the OIE

– 2004: Enhanced surveillance • Test maximum number of animals possible

Specific Guidelines for Hunters Regarding CWD

• Public health officials recommend avoiding human exposure to CWD agent

• Harvest only animals that look and behave normally • Do not eat any animal products of sick or infected elk and

deer • Do not eat brain, spinal cord, eyes, spleen, tonsils and lymph

nodes

• Dress the deer/elk properly

– Minimize handling of brain and spinal tissues

– Wear rubber gloves when field dressing

– Use strong household bleach for cleaning knifes and saws

• Any suspicious elk and deer should be reported to health officials

• Testing of elk and deer available in many states

Prevention and Control

• Surveillance for CJD in US – CDC

• Blood/plasma donation restrictions – Persons who have traveled or resided in the U.K. for 3 or

more cumulative months from 1980 to 1996 – FDA Website www.fda.gov/cber/gdlns/cjdvcjd.pdf

• Scrapie Flock Certification Program

– Voluntary

– Producers-industry-states-APHIS

– Certify origin in scrapie-free flock

• National Accelerated Scrapie Eradication Program

– Live animal testing and active slaughter

– Animal tracing/animal identification

– Clean-up strategies including genotyping

Regulations

• Annex I to European Parliament and council directives for Veterinary 2001/82/EC and for Human medicinal products [2001/83/EC (as amended by commission directive 2003/63/EC)] describes Regulatory compliance through Risk Assessment, Legal Aspects and General Monographs.

• European Pharmacopeia:

Chapter identical with the Note for Guidance on Minimising the Risk of Transmitting Animal Spongiform Encephalopathy Agents via Human and Veterinary Medicinal Products – Revision 3, (EMA/410/01 rev. 3).” 5.2.8. Minimising the risk of transmitting animal spongiform encephalopathy agents via human and veterinary medicinal products

Regulations

• European Pharmacopeia: Has classified a group of animals as “TSE -relevant animal species” (TSE-RAS). It has been classified that Cattle, Sheep, Goats and animals that are naturally susceptible to TSE agents or susceptible to infection through oral route other than humans and non-human primates are defined as “TSE relevant animal species”. Any product/material derived from TSE-RAS like active substances, excipients, adjuvant, raw and starting materials and reagents used in the production should meet the requirements of the Note for Guidance published by EC. Example: Bovine Serum, Enzymes

Regulations

• In unavoidable circumstances, TSE-RAS shall be used in the production for pharmaceutical preparation but it must be fully justified by the applicant and necessary requirement of the note for guidance (EU) should be met.

Regulatory Compliance

• The applicant/MA holder shall consider all the scientific Principles for Minimizing the risk in case use of a TSE-relevant animal species

• Based on the risk assessment strategies/methods applied by the applicant and if it is found adequate, regulatory compliance is certified by EDQM through Certificate of Suitability. However, the final determination of regulatory compliance rests with the competent authority. The application must encompass (along with other requirements) as below – All TSE-risk factors considered for the assessment study – Control measures taken into account – Risk minimized by applicant – Risk Various material derived from TSE-RAS – TSE reduction or inactivation techniques /steps employed – Justification for the selection of the source – Justification for the selection of tissues/body parts/fluids

Regulatory Compliance In case of use of animal origin material, the following shall be verified in general • Type of tissue/body part/fluid used • Type of animal from which the material is required (Ruminant/non-

ruminant/bovine/ Caprine /Ovine/Porcine) • Age of animals/health status from which the material is required • Geographical origin of the animal (Country/Continent) • A detailed risk assessment and expert certification • Type of stunning/slaughtering method employed • Type of certification like ISO, HACCP or GMP of the manufacturer of animal

product manufacturer • Traceability of animal slaughtering source • Methods of segregation of tissues during slaughtering • Potential of cross contamination during slaughtering/Packing/handling • Name, complete address of the supplier • Prior reduction claims from the manufacturer of animal derived products • CEP certification of the pharmaceutical product • Information regarding the Facility of manufacturing animal derived material • Information regarding Products derived from elk, deer