APHIS Factsheet

Veterinary Services August 2010

Nor98-Like 

(Nonclassical) Scrapie

Nor98-like scrapie is a prion disease. Other prion 

diseases include classical scrapie in sheep and goats, 

bovine spongiform encephalopathy (BSE) primarily 

of cattle, chronic wasting disease (CWD) of deer and 

elk, and in humans Creutzfeldt-Jakob disease (CJD) 

and variant Creutzfeldt-Jakob disease (vCJD). What 

each of these diseases has in common is that they 

cause a progressive and ultimately fatal degeneration 

of the nervous system. While the underlying cause(s) 

are still debated, the theory most widely accepted in 

the scientifi c community is that the infectious agent 

is a prion—an abnormal form of a normally occurring 

cellular protein. 

Unlike BSE, classical scrapie and Nor98-like 

scrapie have not been shown to be a threat to human 

health. Classical scrapie has been known to exist for 

over 250 years, and cases have occurred in the United 

States since 1947. It is likely that Nor98-like scrapie 

has also existed for a long time; however, it was fi rst 

identifi ed in Norway in 1998, hence the name Nor98. 

This type of scrapie is referred to as “atypical scrapie,” 

“Nor98 scrapie,” “Nor98-like scrapie,” or “nonclassical 

scrapie.” Since 1998, similar cases have been found 

in almost every country in Europe, as well as Australia, 

Canada, the Falkland Islands, New Zealand, and the 

United States. The fi rst cases in the United States 

were identifi ed in 2007.

Nor98-like (nonclassical) scrapie and classical 

scrapie are separate diseases with distinct features. 

Laboratory fi ndings quickly distinguish Nor98-like 

scrapie from classical scrapie. In 2009, the World 

Animal Health Organization (OIE) recognized Nor98-

like scrapie as a separate disease from classical 

scrapie because of differences in laboratory fi ndings, 

transmissibility, and distribution. This determination 

means that Nor98-like scrapie is not a reportable 

disease to OIE, and should be of no trade concern.

Nor98-like (nonclassical) scrapie Classical scrapie

Transmission Nor98-like scrapie is either not transmitted or is poorly 

transmitted, under natural conditions, meaning thorough 

exposure to infected animals on farms. Many scientists 

believe that Nor98-like scrapie is instead caused by a 

random conversion (often referred to as “sporadic”) of 

the normal prion protein into the abnormal form.

Classical scrapie is an 

infectious disease that is 

transmitted to other sheep 

and goats under natural 

conditions.

Distribution Nor98-like scrapie has been found in all countries 

where extensive surveillance has been conducted using 

sensitive test methods. Nor98-like scrapie cases tend 

to be isolated in many different herds and appear to be 

randomly distributed. 

Classical scrapie has not 

been reported in some 

of the countries where 

Nor98-like scrapie is found. 

Classical scrapie cases 

often occur in clusters.

Number of 

affected sheep 

or goats in a 

fl ock or herd

Nor98-like scrapie is rarely found in more than one 

animal in a fl ock or herd. When an additional case is 

found, it is usually in fl ocks with more than 500 sheep. 

Classical scrapie usually 

infects two or more sheep 

or goats in an infected fl ock.

 
United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture

 APHIS Policy Regarding Nor98-Like Scrapie

APHIS will no longer require the depopulation or 

movement restriction of Nor98-like scrapie-exposed sheep 

and goats. APHIS is planning to propose changes to the 

Code of Federal Regulations (CFR) in 2010 to allow the 

APHIS Administrator to eliminate or reduce post-exposure 

requirements for certain or specifi c scrapie types—such as 

Nor98-like scrapie—that pose minimal risk of transmission 

between animals under natural conditions.

In the meantime, APHIS is conducting a national 

scrapie-control pilot project for Nor98-like scrapie. The 

project involves fl ocks and herds in which animals positive 

for Nor98-like scrapie were born, lambed, or kidded. The 

pilot project will allow producers that have sheep and goats 

exposed to Nor98-like (nonclassical) scrapie to retain, sell, 

exhibit, or move them for any purpose.

Response Measures

If a Nor98-like scrapie case is found in or traced back 

to an owner’s fl ock or herd, certain measures will be 

taken. The owner will be contacted by a Federal or 

State veterinarian who will schedule a visit to the farm 

accompanied by the owner to:

• Confi rm the identifi cation of the positive animal;

• Provide the owner with information about scrapie 

and its control; and

• Determine if the positive animal was born in or gave 

birth in the fl ock/herd. If so, the veterinarian will:

o Work with State animal health authorities 

to ensure animals are not moved from the 

premises until they have been officially 

identifi ed;

o Develop a Nor98-like scrapie fl ock plan and a 

5-year monitoring plan with the producer;

o If not already officially identifi ed, apply official 

eartags to sheep and goats exposed to Nor98-

like scrapie; and

o Inventory all sheep and goats, and any sheep 

or goat embryos.

 The officially identifi ed sheep and goats will 

then be classifi ed and handled as low-risk exposed 

animals, allowing the owner to move the animals from 

the premises for any purpose including sale.

Additional Information

To learn more about classical scrapie, Nor98-like 

scrapie, and any updates to the scrapie control pilot 

project, visit http://www.aphis.usda.gov/animal_health/

animal_diseases/scrapie/.

Nor98-like (nonclassical) scrapie Classical scrapie

Average age 

when clinical 

signs start to

appear in 

animals

 In Nor98-like scrapie, clinical signs are rarely 

documented and the animals are typically diagnosed 

when sampled at slaughter, usually at greater than 

5 years of age.* 

With classical scrapie, 

clinical signs typically fi rst 

appear and result in death 

in animals that are between 

3-5 years of age.

Clinical signs 

associated 

with disease

Clinical signs are rarely reported in Nor98-like scrapie 

cases. Furthermore, intense rubbing against fi xed 

objects has not been reported in Nor98-like scrapie 

cases. 

Intense rubbing against 

fi xed objects is a frequently 

occurring clinical sign in 

classical scrapie cases.

Variations in 

protection 

against the 

disease conferred 

by genotype

In Nor98-like scrapie, no protection is conferred by 

genotype. 

Some sheep have 

genotypes that are resistant 

to classical scrapie but 

are still susceptible to 

Nor98-like scrapie.

* In the few Nor98-like scrapie cases where clinical signs were reported, the signs observed were indistinguishable from those 

described for classical scrapie. These include incoordination, gait abnormalities, collapsing while running, tremors, loss of 

condition, leg biting, behavioral changes and/or nibble response. The nibble response is when a scrapie-affected animal is 

scratched somewhere on its body (usually along its back) and it causes involuntary lip and/or tongue movements.

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