NAHMS Scrapie Genetic Resistance Report Example

National Animal Health Monitoring System
(NAHMS) Scrapie Genetic Resistance Report
Date of report: 11/1/2019
Scrapie genetic resistance test results for NAHMS ID: 999999
Date of sample collection: 10/1/2019
Dear participant,
Thank you for participating in the scrapie genetic resistance testing portion of the NAHMS Goat
2019 Study. This report contains results of the scrapie genetic resistance testing performed on
goats at your operation. Please consider sharing these results with your veterinarian.
If you have questions about the accuracy of your results, please contact Dr. Alyson Wiedenheft,
the NAHMS biologics coordinator, at (970) 494-7290 or Alyson.M.Wiedenheft@aphis.usda.gov.

Background on Scrapie:

Classical scrapie is an infectious degenerative disease affecting the central nervous system of
sheep and goats and is believed to always be fatal. Scrapie is caused by an infection with a
disease-causing agent known as a prion. Prions form abnormal protein deposits in the central
nervous system, which disrupt the normal nervous system structure resulting in progressive
neurological degeneration. The earliest clinical sign of classical scrapie is often subtle changes
in behavior, which may be followed by scratching against fixed objects, loss of coordination,
weight loss despite retention of appetite, biting of own feet and limbs, lip smacking, or gait
abnormalities or a combination of these. Loss of coordination is the most common sign
reported.
Scrapie can be transmitted from infected does during or following kidding when herd mates or
newborn kids ingest the infected placenta, birthing fluids or contaminated bedding. Once
infected, the animal remains infected for life.

Genetic Resistance Testing and Reported Results:

Blood samples collected from goats on your operation were tested for the presence of the two
alleles (alternative forms of the same gene) that appear to make goats more resistant to
classical scrapie, Serine-146 (S146) and Lysine-222 (K222). S146 is the protective variant of
the normal gene Asparagine-146 (N146). K222 is the protective variant of the normal gene
Glutamine-222 (Q222). Evidence shows that goats with a single copy of either of these
protective alleles have been resistant to scrapie infection during natural disease outbreaks and
also direct challenge experiments but not fully resistant similar to what is seen with QR sheep.
Scrapie resistance alleles in goats have not been formally recognized in the United States, so
genetic testing in goats is not considered official testing for scrapie program purposes.

Genetic Resistance Interpretation Key:
Genetic Resistance Interpretation
No resistance to classical scrapie

146

222

NN

QQ

One copy of protective variant K222, increased resistance to classical
scrapie

NN

QK

Two copies of protective variant K222, increased resistance to classical
scrapie

NN

KK

One copy of protective variant S146, increased resistance to classical
scrapie

NS

QQ

Two copies of S146 protective variant. Increased resistance to classical
scapie

SS

QQ

One copy each of S146 and K222 protective variants. Increased resistance
to classical scrapie
NS

QK

Individual Goat Scrapie Genetic Resistance Test Results:
Sample #
1
2
3
4
5

Goat name/ID
Patty
Alice
Jackie
Willa
Jane

146
NN
NN
NS
SS
NN

222
QQ
QQ
QQ
QQ
KK

Interpretation of results (alleles present):
One or more of the goats tested on your operation were found to have either of the two alleles,
S146 and K222, that appear to make goats resistant to classical scrapie. This genotyping
information can be used to select breeding stock to increase the frequency of the beneficial
alleles within the herd. Breeding for resistance could help prevent classical scrapie
transmission.
Interpretation of results (alleles not present):
No goats tested on your operation were found to have either of the two alleles, S146 or K222,
that appear to increase resistance to classical scrapie. Including goats in your breeding stock
with these alleles may provide increased resistance to classical scrapie in your herd.