CWD PROGRAM 

STANDARD 

REVISIONS:

OVERVIEW OF 

CHANGES

U.S . DEPARTMENT OF AGRICULTURE

ANIMAL AND PLANT HEALTH INSPECTION SERVICE

VETERINARY SERVICES

CERVID HEALTH PROGRAM
Program Standards Working 

Group 2016 and Public 

Comments

Working Group Participants

• Scientific Experts

• State and Federal animal health and wildlife officials

• Farmed cervid representatives
General Changes:

•Streamlined and clarified

•Aligned definitions and terms with the CFR
Content Changes:

 Consequences of poor quality and missing samples

 Ante mortem diagnostics

 Sample Collection and Submission

 Epidemiological Investigations

 Evaluation & prioritization of requests for Federal indemnity

 Biosecurity recommendations for farmed cervid facilities
Consequences of Poor Quality

and 

Missing Samples

Missing and poor sample quality continues to be an issue that

threatens the efficacy, and confidence in, the HCP

New content lists consequences that participating

States may wish to implement in response 
1) Replace missed or poor quality samples with samples from an 

equal number of animals of the same sex and species that resided

in the herd at least as long as the missed animal.

Consequences should include:

2) Reduce herd status – loss, reduction, or delay in certification

3) Direct suspension of herd status for a designated period of time

A number of examples are given for herd status 

adjustments to account for poor quality, incomplete, 

or missing samples
Language in the revised Program Standards was update to 

reflect the requirement in the CFR (Part 55, Subpart B, 55.23-11(3))

that all mortalities, including animals taken to slaughter, must be 

made available for CWD tissue sampling. 

Slaughter Surveillance
Ante Mortem Diagnostics

Who

What

Where

Why

When

How
Who? 

 White-tailed deer

Elk

Ante Mortem Diagnostics
Ante Mortem Diagnostics

What? 

Rectal Biopsy

MRPLN Biopsy

by

Immunohistochemistry

(IHC)

 Serial

 Whole Herd
Ante Mortem Diagnostics

Where? 

Must be outlined in the 

Herd Plan

Testing timeline will also be 

established in the herd plan
Ante Mortem Diagnostics

Why? 

To provide producers under 

trace-out quarantine with an 

option to restore 

business continuity 

faster
Ante Mortem Diagnostics

When? 

 Epi-linked herds 

 CWD-exposed herds

Not routine surveillance

Not CWD-positive herds 
 Herd Codon 96 Genotype ratio is known

 > 50% GG ratio in herd required to utilize ante

mortem diagnostics

 Genotype at codon 96 in white-tailed deer 

strongly influences the incubation period and 

thus the ability of an ante mortem test to 

detect disease

 When GG>GS>SS

When? 
Ante Mortem Diagnostics

How? 

Detailed procedures given 

 Collection

 Submission
Ante Mortem Sample Collection and 

Submission 

Fresh: Blood 3-5 mL whole blood in EDTA for 

codon 96 genetics (chilled or frozen)

Fixed: Rectal Biopsy 1 cm x1.5 cm [NVSL]

Fixed: MRPLN Biopsy 2 cm x 1cm x 1 cm 

(40 follicles req) [NVSL]
Sample Collection and Submission 

Ante Mortem Diagnostics

 Ante mortem biopsies to be collected only by trained 

State, Federal, or accredited veterinarians and must be 

monitored by state animal health or VS representatives

 Testing must be done by NVSL at the owner’s expense

 Samples must be submitted within 7 days of collection
Post Mortem Diagnostics
Sample Collection

Samples should be 

submitted within 7 days 

of collection

Hoarding Hurts!

 Take care with sample ID

 Carefully & accurately label samples
Sample Collection

New requirements for

Fixed and Fresh 

post mortem regulatory samples
Sample Collection and Submission 

Fixed: obex

Place into 10% formalin jar that is clearly and 

appropriately labeled

Obex

Brain Stem Brain Stem
Sample Collection and Submission 

Fresh: brain stem

Place the pieces of brain stem into the whirl pak with 

the halves of the MRPLN. Keep chilled

Obex

Brain Stem Brain Stem
Sample Collection and Submission 

Fixed: medial retropharyngeal lymph nodes (MRPLN)

Longitudinally cut (1/2 of left, 1/2 of right) and place in 

the 10% formalin jar with the obex

Left Right
Sample Collection and Submission 

Fresh: medial retropharyngeal lymph nodes (MRPLN)

Place 1/2 of left, 1/2 of right of each LN that was not placed in 

formalin into a labeled whirl-pak. Keep chilled

Left Right
Sample Collection and Submission 

Fresh: official ID and skin

Place the ear or other skin (~ 1” X 1”) with official ID

attached into the whirl pak with the MRPLN & brain 

stem
Sample Labeling

Date of collection

Producer name

Species

Type of specimen

Official ID

Sample ID number (what is assigned on the NVSL 10-4)
1) CWD-Positive Herd:

Where CWD-positive animal resided at time of diagnosis.

2) Epidemiological-Linked Herd: a herd where the CWD-exposed 

animal(s) have resided with a CWD-positive animal within 5 years 

prior to the diagnosis of CWD in the positive herd or from the 

identified date of entry of CWD into the positive herd and have since 

moved to or through other herds. An Epi –Linked herd can be a Traceback Epi-linked, Trace- forward Epi-linked or Pass-through Epi-linked.

Epidemiological Investigations

Classification of animals and herds
Epidemiological Investigations

Response options are given for all types of herds

Required CWD Epidemiology Investigation and 

Report templates are provided in Appendix VI
Trace-forward Herd (Epi-linked Herd)

Quarantine:

Animal Present

Quarantine:

Animal Absent

Quarantine 5yr Test

Possible Ante

Mortem Testing Positive Herd

Non-Detect Positive

Release 

Quarantine Positive Herd

Any herd(s) where an animal from a CWD-positive herd resided in 

the last 5 years
Any herd(s) where the CWD-positive animal resided in the last 5 

years

Trace Back Herd (Epi-Linked Herd)

Quarantine

Quarantine 5yr

Possible Ante

Mortem Testing

Positive Herd
Positive Herd

Pass-through (Epi-linked Herd)

Pass-through

Epi-linked herd

Evaluation & Prioritization: Requests 

for Federal Indemnity

 Availability of funds

 Herd size (as related to availability of 

funds)

 Herd status (CWD-positive >whole 

herds with exposed or suspects)

 Type of herd (breeding>hunt preserve)
 HCP status (enrolled and 

compliant> not enrolled or noncompliant)

 CWD status of surrounding area 

(not detected in wildlife>not 

detected in wildlife)

 Cervid density in local area 

(high>moderate>low)

 Value of post mortem testing to 

inform epi and decision making
Biosecurity Recommendations for 

Farmed Cervid Facilities

Procedures to reduce

the risk of introducing CWD 

and other diseases to a 

farm
Biosecurity Recommendations for 

Farmed Cervid Facilities

Prevent direct contact between cervids and wildlife:

Wild cervids

Birds

Feral hogs

Other animals

VerCauteren NWRC
Biosecurity Recommendations for 

Farmed Cervid Facilities

Prevent indirect contact with potentially contaminated 

objects or materials

Feed and Hay

 Humans 

Vehicles

Equipment