Caprine Arthritis Encephalitis (CAE) Virus
Caprine arthritis encephalitis (CAE) is a member of the small ruminant
lentiviruses (also includes ovine progressive pneumonia-OPP of sheep) which may
lead to chronic disease of the joints, and on rare occasions, encephalitis in
goat kids less than six months of age. The CAE virus is intimately associated
with white blood cells; therefore, any body secretions which contain blood cells
are potential sources of virus to other goats in the herd. Since not all goats
that become infected with CAE virus progress to disease, it is important to test
goats routinely for infection by means of a serology test which detects viral
antibodies in the serum.
WSU-WADDL receives numerous inquiries about CAE virus, how to test for it,
and most importantly, how to take steps to control the infection in goat herds.
It is important to remember that â€˜goat infection statusâ€™ not clinical disease,
is the element of interest in assessing risk factors and designing control
programs for CAE virusâ€™ (Rowe & East, 1997). We have taken some of the most
frequently asked questions and presented them along with some short answers.
Click on a question or
The CAE virus is primarily transmitted to kids via colostrum in the first
few feedings after birth. Blood (e.g., contaminated instruments such as needles,
dehorners, etc, and open wounds) is regarded as the second most common way of
spread. Contact transmission between adult goats is considered to be rare except
The diagnostic laboratory provides services to veterinarians. Although we
will test goat serum samples mailed directly from an owner, we strongly
encourage goat owners to work with a veterinarian in developing a CAE control
program. We will send results to the veterinarian, and also to the owner if
We recommend working with your veterinarian to obtain appropriate samples.
Blood should be collected into a five or ten ml. "red-top" clot tube or serum
separator tube. Leave the blood at room temperature for at least 1 hour to allow
clot formation. We do not recommend separating the serum from the clot prior to
shipment. Send blood sample(s) to the lab by overnight mail (FedEx (choose
"Standard Overnight" for quickest delivery), UPS, or USPS).
It is not necessary to individually wrap each tube. The best method is to use
padded pouches designed for blood tubes. If you do not have access to these, we
recommend using a thick rubber band and grouping your tubes tightly into groups
of 7-10 tubes. If you alternate the direction of the tubes they will stay
tightly packed. Pack the tubes in a plastic sealable bag with absorbent material
in with the tubes, and put another plastic bag around the first. Pack so the box
can be dropped from a four foot height without breaking any tubes! An ice pack
is recommended if the shipment is expected to take several days in warm weather.
If you chose to ship using Federal Express, specify "Standard Overnight
Service." Overnight package delivery should be sent to: WSU- WADDL Bustad
Hall, Room 155N Pullman WA 99164-7034
In-state (WA) costs are a $10 accession fee per case, and $4.20 for each
sample. Costs for out-of-state residents are a $10 accession fee and $6.30 for
each sample. Please make a check payable to "WADDL" for the proper amount.
State submission of 7 goat samples
|Testing (7 x $4.20)
Out-of-State submission of 7 goat samples
|Testing (7 x $6.30)
CAE competitive ELISA (cELISA) tests are generally run once a week,
on Thursday morning, with reports going out on Friday. During busy
times, the test may be set more than one time per week. However, to be
tested on Thursday, samples must arrive by Wednesday afternoon. Test
results can be telephoned or faxed to the veterinarian and/or owner upon
request. Veterinarians also can access laboratory reports electronically
â€œon-lineâ€; please call the lab to receive a secure web log-in (username
and password). For security reasons WADDL does not e-mail laboratory
A positive result means the goat has been infected with the CAE virus and has
made antibodies reactive with the CAE antigens used in this test. This goat is
regarded as potentially contagious for the virus, especially if lactating. The
antibody against CAE is not a protective antibody and infectious virus can still
be spread in milk and blood of this goat. As many as 90% of positive goats may
be free of clinical signs of the disease, and remain so for years or life. A
young goat not infected with CAE virus which has received heat-treated colostrum
containing CAE antibodies may also test antibody positive for several months
because of passive transfer of maternal antibodies from the colostrum. We
recommend re-testing these kids after six months of age to determine their true
infection status. A negative result means that this goat is either not infected,
or has been recently infected and is producing amounts of antibody too low to be
detected. While the latter case does not appear to be common, it is a good
reason to retest all negative goats when not in a closed herd. Goats that are
negative should be periodically tested (twice a year for the 1st year, and
Goats infected with CAE virus are infected for life. Thus a goat tested
true positive by the CAEV cELISA test would not later clear the CAE
virus infection. Occasionally a very young animal, fed heat-treated
colostrum containing CAE antibodies may test positive and later negative
from the decline of passively acquired antibodies in the colostrum. In
some goats, seroconversion may be delayed for months after exposure.
These "silently" infected animals test negative for antibody until the
viral infection is activated by stress or other factors. It has not been
determined whether these goats were infectious to other goats during the
time they harbored the virus but remained seronegative. Lastly, although
the CAEV cELISA test is a USDA licensed test showing excellent ability
to detect CAE virus antibody true positive results it is not perfect
test. The commercial manufacturer of the cELISA test publishes a test
specificity of 99.6%, which means 4 in 1000 tests could generated a
false positive result that upon retesting could test seronegative.
Yes, WADDL has a validated and USDA licensed (cELISA) for CAE virus
antibodies. This test is more sensitive (ability to detect true positive animal)
than the agar gel immunodiffusion (AGID) test (sensitivity of 85%-90% and
specificity of 100%). Values for the CAE cELISA have been set by double testing
goat sera by ELISA and a very sensitive research assay, called
immunoprecipitation. The positive cutoff score for the cELISA had a sensitivity
of 100%, and specificity of 99.6%, which means there is a false positive rate of
4 out of every 1,000 samples tested.
There is NO evidence that the CAE virus is transmissible to humans.
However, there are other serious human pathogens which have been
transmitted through raw milk. Consult your veterinarian regarding the
public health hazards of consuming raw milk.
We recommend this screen for new animals entering the herd and animals
producing milk for human consumption. This screen includes CAE, Johne's Disease,
caseous lymphadenitis and Brucella. Tests are priced individually.
|Caprine Arthritis Encephalitis
Heat treating colostrum will inactivate the CAE virus and prevent spread
from the doe to her offspring. Colostrum from any doe may be heated to
between 133 degrees and 138 degrees F (56 to 59 degrees C) and held at
that temperature for one hour to inactivate the virus. An accurate
thermometer is important. It is recommended to use a water bath or
double boiler to regulate the temperature more closely. A large batch
may be heat-treated and frozen in small feeding size portions for later
use (about one pint per kid). If heated higher than 140 degrees F, the
usefulness of the colostrum will be greatly reduced due to denaturing of
beneficial proteins, including antibodies to other infectious
Twice a year initially followed by annual testing is suggested for herds
which are primarily negative, with testing before kidding recommended. Any new
animals brought into the herd should be quarantined and tested twice (at least
30 days apart) before introduction with other negative animals. In addition to
CAE infection, new goats should be tested for Johneâ€™s disease, and Brucellosis
as a biosecurity screen (see #12). For herds with both positive and negative
animals, negative animals should be tested more often to adjust the milking
order so that negative animals are milked first.
Yes. WADDL is working with USDA scientists in the development of a
polymerase chain reaction (PCR), which tests for CAE virus specific nucleic
acid. Current PCR assays have lower specificity (more false positives) than the
antibody assays. The PCR assay may become practical and financially affordable
enough for routine testing, especially in goats that have delayed
Additional information on CAE virus and other infections of livestock
can be obtained by contacting your local veterinarian or the diagnostic
laboratory at 509-335-9696, FAX 335-7424.
1. Rowe, JD and NE East: Risk factors for transmission and methods for
control of caprine arthritis-encephalitis virus infection. Vet Clinics
No Amer 13:35-53, 1997.
2. Adams, DS, et al: Transmission and control of caprine
arthritis-encephalitis virus. Am J Vet Res 44:1670-1675, 1983.
3. Vander Schalie, J, et al: Evaluation of a kinetic enzyme linked
immunosorbent assay for detection of caprine arthritis-encephalitis
virus-specific antibodies. J Vet Diagn Invest 6, 30-33, 1994.
4. Evermann, JF: Control of CAE virus takes work and periodic
testing. United Caprine News. Winter, 2002 update.
5. Steele, JH: History, trends, and extent of pasteurization.
J. Am Vet Med Assoc 217:175-178, 2000.
6. Greenwood, PL et al.: Prevalence, spread and control of
caprine arthritis-encephalitis virus in dairy goat herds in New South
Wales. Aust. Vet. J. 72:341-345, 1995.
7. Nord, K et al.: Control of caprine arthritis-encephalitis
virus and Corynebacterium pseudotuberculosis infection in Norwegian goat
herd. Acta Vet Scand 39:109-117, 1998.
8. Ozyoruk, F et al.: Monoclonal antibodies to conformational
epitopes of the surface glycoprotein of caprine arthritis-encephalitis
virus. Potential application to competitive-inhibition enzyme-linked
immunosorbent assay for detecting antibodies in goat sera. Clin Diag Lab
Immunol 8:44-51, 2001.
9. Cebra, C and M Cebra: Caprine arthritis-encephalitis virus
infection. In Pugh, DG: Sheep and Goat Medicine, W.B. Saunders, Co.
Phil, 2002, pp 388-389.
10. Fieni, F et al.: Presence of caprine
arthritis-encephalitis virus (CAEV) infected cells in flushing media
following oviductal-stage embryo collection. Therigenol 57:931-940,
11. Rolland, M et al.: Characterization of an Irish caprine
lentivirus strain - SRLV phylogeny revisited. Virus Res 85:29-39, 2002.
12. Peterhans, E et al: Routes of transmission and consequences
of small ruminant lentiviruses (SRLVs) infection and eradication
schemes. Vet Res: 35:257-274, 2004.
13. Bertoni, G. Caprine arthritis encephalitis complex. In
Recent Advances in Goat Diseases, Intl Vet infor Service, NY
14. Brinkhof, J and Van Maanen, C: Evaluation of five
enzyme-linked immunosorbent assays and an agar gel immunodiffusion test
for detection of antibodies to small ruminant lentiviruses. Clin vacc
Immunol 12:1210-1214, 2007.
15. Herrmann-Hoesing, L: Diagnostic assays used to control small
ruminant lentiviruses. JVDI 22:843-855, 2010.
Contacts on CAE
Dr. James Evermann
Dr. Kerry Sondgerath