Upload
patrick-cunningham
View
220
Download
0
Tags:
Embed Size (px)
Citation preview
USDA Licensed Test USDA Licensed Test Kits and Enhanced Kits and Enhanced Surveillance for BSESurveillance for BSE
Larry LudemannLarry Ludemann11 and and Lawrence ElskenLawrence Elsken22
Policy, Evaluation, and LicensingPolicy, Evaluation, and Licensing11
Inspection and ComplianceInspection and Compliance22
Center for Veterinary BiologicsCenter for Veterinary BiologicsVeterinary ServicesVeterinary ServicesAnimal and Plant Health Inspection Animal and Plant Health Inspection ServiceServiceUnited States Department of AgricultureUnited States Department of Agriculture510 S. 17510 S. 17thth Street, Suite 104 Street, Suite 104Ames, Iowa 50010 USAAmes, Iowa 50010 USA
The Causative Agent of TSEsThe Causative Agent of TSEs
PrionsPrions• Abnormally folded proteinAbnormally folded protein
Not a virus. Not a bacteria. No DNA or RNANot a virus. Not a bacteria. No DNA or RNA No known immune responseNo known immune response
• Two forms of prion proteinTwo forms of prion protein Normal prion protein (PrPc) – on most cellsNormal prion protein (PrPc) – on most cells Infectious Prion (PrPSc)Infectious Prion (PrPSc)
• Relatively resistant to disinfectants, sterilizations, Relatively resistant to disinfectants, sterilizations, proteinasesproteinases
• Accumulates and kills the cellsAccumulates and kills the cells
BSE: DiagnosticsBSE: Diagnostics
No effective live animal test for BSENo effective live animal test for BSE Need brain tissueNeed brain tissue Histopathology of brainHistopathology of brain IHC, WB, ELISA – PrPIHC, WB, ELISA – PrPresres
““Negatives” do not guarantee Negatives” do not guarantee absence of infectivity - tests are NOT absence of infectivity - tests are NOT intended as “Food Safety Tests”intended as “Food Safety Tests”
BSE Diagnostic TestsBSE Diagnostic Tests Histology ImmunoHistochemistry ImmunoHistochemistry
(IHC)-(IHC)-an ELISA performed on a tissue section mounted on a slide
“Rapid tests”- ELISA, EIA, Western Blot
““Rapid Tests”Rapid Tests”
As name implies, generally more rapid As name implies, generally more rapid than IHCthan IHC
Associated with occasional “false positive” Associated with occasional “false positive” initial reactions (especially ELISA)initial reactions (especially ELISA)
Western Blot Test lower throughput, Western Blot Test lower throughput, slower, and more involved than ELISAslower, and more involved than ELISA
All approved tests have very good All approved tests have very good sensitivity and specificitysensitivity and specificity
BUT - only serve as screening testsBUT - only serve as screening tests
IMMUNOHISTOCHEMISTRYIMMUNOHISTOCHEMISTRY
Adds immunological confirmation to Adds immunological confirmation to observation of lesionsobservation of lesions
Stain observed in specific (definitive) Stain observed in specific (definitive) anatomic areas associated with BSEanatomic areas associated with BSE
No “false positives”No “false positives” Generally requires several days to Generally requires several days to
complete testcomplete test
January 8, 2004January 8, 2004
CENTER FOR VETERINARY BIOLOGICS NOTICE NO. 04-02CENTER FOR VETERINARY BIOLOGICS NOTICE NO. 04-02
Subject: Diagnostic Test Kits for Bovine Spongiform EncephalopathySubject: Diagnostic Test Kits for Bovine Spongiform Encephalopathy
To: To: Biologics Licensees, Permittees, and ApplicantsBiologics Licensees, Permittees, and ApplicantsVeterinary Services Management TeamVeterinary Services Management TeamDirectors, Center for Veterinary BiologicsDirectors, Center for Veterinary BiologicsArea Veterinarians in Charge, VSArea Veterinarians in Charge, VSState VeterinariansState Veterinarians
I. PURPOSEI. PURPOSE
The purpose of this notice is to inform interested parties that the Center for Veterinary Biologics (CVB)The purpose of this notice is to inform interested parties that the Center for Veterinary Biologics (CVB)is accepting veterinary biologics product license and permit applications for diagnostic test kits is accepting veterinary biologics product license and permit applications for diagnostic test kits (including “rapid tests”) intended as an aid in the diagnosis of bovine spongiform encephalopathy (including “rapid tests”) intended as an aid in the diagnosis of bovine spongiform encephalopathy (BSE).(BSE).
II. Background
Numerous test methods (e.g., immunohistochemistry, ELISA, Western blot) and commercial test kits have been developed to aid in the diagnosis of BSE. Some of these kits have been approved by foreign regulatory officials (e.g., European Union, Japan) for use in their BSE testing programs. Due to recent confirmed cases of BSE in North America and the anticipated increase in surveillance for BSE inthe U.S., the CVB will accept and consider license and permit applications for diagnostic test kits intended to aid in the diagnosis of BSE.
The CVB will proceed with the review and testing processes of each license or permit application up to the point of issuing the actual U.S. Veterinary Biological Product License or Permit. In the future, the CVB will issue additional guidance on the final U.S. Veterinary Biological Product License or Permit restrictions required for distribution and sale of these diagnostic test kits in the U.S.
Authorities, Regulations, & GuidanceAuthorities, Regulations, & Guidance Virus-Serum-Toxin Act: 21 USC Virus-Serum-Toxin Act: 21 USC
• Authorizes Secretary of Agriculture to Authorizes Secretary of Agriculture to regulate manufacture and distribution of regulate manufacture and distribution of biologics including diagnostics (test kits) biologics including diagnostics (test kits) intended for use in diagnosis of disease in intended for use in diagnosis of disease in animals.animals.
Code of Federal Regulations: Title 9 Code of Federal Regulations: Title 9 VS Memoranda VS Memoranda
• 800.73 (Immunodiagnostic Test Kits), 800.73 (Immunodiagnostic Test Kits), othersothers
What is a regulated test kit?What is a regulated test kit?
Diagnostic test kits contain:Diagnostic test kits contain:• All unique reagents required to conduct testAll unique reagents required to conduct test• Complete instructions for the testComplete instructions for the test• Instructions for interpretation of test resultsInstructions for interpretation of test results• Claims, uses, and limitationsClaims, uses, and limitations
Used to diagnose existence of (usually) or Used to diagnose existence of (usually) or susceptibility to disease agents of animalssusceptibility to disease agents of animals
Reagents are not regulatedReagents are not regulated
Prelicense Assessment of KitsPrelicense Assessment of Kits
Accuracy and precisionAccuracy and precision Diagnostic sensitivityDiagnostic sensitivity
• Dynamic rangeDynamic range• Analytical sensitivityAnalytical sensitivity
Diagnostic specificityDiagnostic specificity Ruggedness, repeatability, suitabilityRuggedness, repeatability, suitability Predictive values for specific disease Predictive values for specific disease
prevalence (especially for Program Diseases)prevalence (especially for Program Diseases)
Prelicense ValidationPrelicense Validation Test large number of known positive and Test large number of known positive and
known negative animal samples covering a known negative animal samples covering a range of reactions and all sample typesrange of reactions and all sample types
Determine onset of detection of diseaseDetermine onset of detection of disease Evaluate (in at least 3 laboratory settings)Evaluate (in at least 3 laboratory settings)
• Serum or antigen panel (ruggedness)Serum or antigen panel (ruggedness)• Well-characterized patient samplesWell-characterized patient samples• Compared to “Gold” standard assayCompared to “Gold” standard assay• Suitability of test kitSuitability of test kit• Adequacy of instructionsAdequacy of instructions
Authorization from USDA per 9 CFR 103.3 Authorization from USDA per 9 CFR 103.3 (experimental biological products)(experimental biological products)
Manufacturing controlsManufacturing controls Aim is to minimize within-serial and serial-to-Aim is to minimize within-serial and serial-to-
serial variation by ensuring consistency of serial variation by ensuring consistency of production – production – Outline of ProductionOutline of Production
Master Seed/Master Cell conceptMaster Seed/Master Cell concept Validation of new lots of antibody/antiseraValidation of new lots of antibody/antisera Serial release testing of serum or antigen Serial release testing of serum or antigen
panel with range of reactivities and cross-panel with range of reactivities and cross-reactivitiesreactivities• Serial release panel is critical to minimize variation Serial release panel is critical to minimize variation
in test resultsin test results• Panel includes range of reactivityPanel includes range of reactivity
Other RequirementsOther Requirements Inspection of manufacturing facilities Inspection of manufacturing facilities
and other licensed sites (e.g., and other licensed sites (e.g., Permittee quarantine sites)Permittee quarantine sites)
Prelicense serial testingPrelicense serial testing Label approvalLabel approval
USDA Approved Bovine Spongiform Encephalopathy Antigen Test KitsUSDA Approved Bovine Spongiform Encephalopathy Antigen Test Kits(Permits, as of September 30, 2004)(Permits, as of September 30, 2004)
Manufacturer Manufacturer Kit Format Kit Format Trade Name Trade Name Date Approved Date Approved
Bio-Rad Bio-Rad Laboratories,Laboratories,
(permittee: Bio-Rad, (permittee: Bio-Rad, France) France)
ELISAELISA TeSeE® TeSeE® Permit issued:Permit issued:
March 17, 2004 March 17, 2004
Abbott LaboratoriesAbbott Laboratories
(permittee: Enfer, (permittee: Enfer, Ireland) Ireland)
ELISAELISA Enfer BSE Enfer BSE Permit issued:Permit issued:
May 28, 2004 May 28, 2004
Roche Diagnostics Roche Diagnostics Corp.,Corp.,
(permittee Prionics, (permittee Prionics,
Switzerland) Switzerland)
Western BlotWestern Blot Prionics®- Prionics®- Check Check Western Western
Permit issued:Permit issued:
May 28, 2004 May 28, 2004
USDA Approved Bovine Spongiform Encephalopathy Antigen Test KitsUSDA Approved Bovine Spongiform Encephalopathy Antigen Test KitsLicenses, as of (September 30, 2004)Licenses, as of (September 30, 2004)
Manufacturer Manufacturer Kit Format Kit Format Trade Name Trade Name Date Approved Date Approved
IDEXX Laboratories, IDEXX Laboratories, Inc. Inc.
EIA (Enzyme EIA (Enzyme ImmunoassaImmunoassay) y)
HerdChek- HerdChek- BSE BSE
License issued:License issued:
March 17, 2004 March 17, 2004
Pierce Pierce Biotechnology, Inc., Biotechnology, Inc.,
(Produces kit for (Produces kit for Prionics) Prionics)
ELISAELISA Prionics®- Prionics®- Check LIA Check LIA
Licensed:Licensed:
September 1, September 1, 2004 2004
Pierce Pierce Biotechnology, Inc., Biotechnology, Inc.,
For Export OnlyFor Export Only
ELISAELISA
BSE-ScrapieBSE-Scrapie
Ag Test KitAg Test Kit
Prionics®- Prionics®- Check LIA Check LIA
Licensed:Licensed:
September 1, September 1, 2004 2004
VMRD, Inc. VMRD, Inc.
For Export OnlyFor Export Only
IHCIHC License issued:License issued:
August 5, 2004 August 5, 2004
Licensed BSE Test Kits:Licensed BSE Test Kits:Format or TechniqueFormat or Technique
All use obex tissueAll use obex tissue Purify normal and abnormal PrPPurify normal and abnormal PrP Treatment to “remove” normal PrPTreatment to “remove” normal PrP
• Western Blot – separate protein by Mol WtWestern Blot – separate protein by Mol Wt Antibody binds “abnormal” PrPAntibody binds “abnormal” PrP Indicator enzyme (on antibody) produces Indicator enzyme (on antibody) produces
“visible” reaction: “visible” reaction: • ELISA, EIA, chemiluminescence, solid precipitate ELISA, EIA, chemiluminescence, solid precipitate
(Western Blot, IHC)(Western Blot, IHC)
Diagnostics: Under DevelopmentDiagnostics: Under Development
““Cowside” or on-site testsCowside” or on-site tests Capillary electrophoresis – bloodCapillary electrophoresis – blood Blood – other methodologies - Blood – other methodologies -
CaptureCapture Urine – UPrPscUrine – UPrPsc Increased sensitivity – cyclic Increased sensitivity – cyclic
amplificationamplification Non-PrP markers – “Upregulated” Non-PrP markers – “Upregulated”
MarkersMarkers
What does licensure provide?What does licensure provide? USDA controlled manufacturing of all USDA controlled manufacturing of all
components and kitscomponents and kits• Minimal variation within and between serialsMinimal variation within and between serials
USDA evaluation of test kit before and after USDA evaluation of test kit before and after licensure (serial release)licensure (serial release)
Monitoring of field performance and Monitoring of field performance and investigations investigations • CVB-Inspection and Compliance 800-752-6255CVB-Inspection and Compliance 800-752-6255
Ongoing facilities inspectionsOngoing facilities inspections Questions? Questions? www.aphis.usda.gov/vs/cvb/www.aphis.usda.gov/vs/cvb/
BSE Surveillance ProgramBSE Surveillance Program
Expanded or Enhanced surveillance Expanded or Enhanced surveillance began June 1, 2004. Purpose:began June 1, 2004. Purpose:• Determine if BSE is present in U.S. cattle Determine if BSE is present in U.S. cattle
populationpopulation• Determine if risk-management policies Determine if risk-management policies
adequateadequate For animal health – NOT food safetyFor animal health – NOT food safety
EU testing: Jan-Dec 2001EU testing: Jan-Dec 2001
SamplesSamples PositivePositive % % positivepositive
RiskRisk 776,266 776,266 756756 .097%.097%
Em slaugEm slaug 96,774 96,774 324324 .335%.335%
CNSCNS 27,991 27,991 3434 .121%.121%
FallenFallen 651,501 651,501 397397 .061%.061%
HealthyHealthy 7,677,5767,677,576 279279 .0036%.0036%
SuspectSuspect 3,267 3,267 11031103 33.76%33.76%
BSE Surveillance ProgramBSE Surveillance Program
Experience in Europe has demonstrated that targeting surveillance efforts at certain high risk populations is the most effective way to identify BSE, if it is present.
BSE Surveillance ProgramBSE Surveillance Program
US high-risk population estimate: US high-risk population estimate: about 446,000 about 446,000 • 246,000 on-farm deaths with 246,000 on-farm deaths with
unexplained causes or causes consistent unexplained causes or causes consistent with BSEwith BSE
• 200,000 ante-mortem condemnations 200,000 ante-mortem condemnations by FSISby FSIS
• 129 (2004 data) Foreign Animal Disease 129 (2004 data) Foreign Animal Disease investigations for CNS disease investigations for CNS disease
BSE Surveillance ProgramBSE Surveillance Program The majority of samples from the following The majority of samples from the following
categories:categories:• Nonambulatory cattle; Nonambulatory cattle; • Cattle exhibiting signs of a central nervous Cattle exhibiting signs of a central nervous
system disorder; system disorder; • Cattle exhibiting other signs that may be Cattle exhibiting other signs that may be
associated with BSE, such as emaciation or associated with BSE, such as emaciation or injury; and injury; and
• Dead cattle. Dead cattle. USDA personnel will also sample all cattle USDA personnel will also sample all cattle
condemned on ante-mortem inspection by condemned on ante-mortem inspection by USDA’s Food Safety and Inspection Service.)USDA’s Food Safety and Inspection Service.)
BSE Surveillance ProgramBSE Surveillance Program
If 268,500 samples are obtained from a target population of 446,000, and if no positives were found after completion of the testing plan, then we can state that we are 99 percent confident that there were less than 5 positive animals in the target population
BSE Surveillance ProgramBSE Surveillance Program
Enhanced surveillance plan Enhanced surveillance plan background, statistical background, statistical inferences:inferences:• http://cofcs66.aphis.usda.gov/lpa/http://cofcs66.aphis.usda.gov/lpa/
issues/bse/bse.htmlissues/bse/bse.html
BSE Surveillance ProgramBSE Surveillance Program
As of October 10, 2004, no positive As of October 10, 2004, no positive BSE test results in Enhanced BSE test results in Enhanced Surveillance ProgramSurveillance Program• Cumulative “rapid” tests from June 1, Cumulative “rapid” tests from June 1,
2004 – October 10, 2004: 79,7662004 – October 10, 2004: 79,766• Also 1,583 IHN negative testsAlso 1,583 IHN negative tests• Currently: More than 5,000/weekCurrently: More than 5,000/week• http://www.aphis.usda.gov/lpa/issues/http://www.aphis.usda.gov/lpa/issues/
bse_testing/test_results.htmlbse_testing/test_results.html