Goat CAE FAQ
Q. What is CAE?
A. Caprine Arthritis and Encephalitis is a widespread condition in goats that, in a majority of instances, will be transmitted to goat kids by infected does unless proper preventative measures are taken.
The effects of CAEV are not always visible. CAE is a retrovirus that can infect both kids and adults, but most kids do not exhibit any serious symptoms until they get older in age. The most common symptoms in kids are encephalitic seizures, while adults display swollen knees or hocks, but these can also be symptoms of injury or contagious arthritis. The easiest method to identify a CAE-infected animal is through blood tests (either ELISA or PCR). The ELISA test is an indirect test and is best for active infections since it detects the presence of antibodies against the active virus, but has limitations if the virus is dormant. The PCR-based test is a direct test in that it detects the presence of the viral genome in both active and dormant infections.
Q. How does the VMRD, Inc. cELISA test kit detect CAE?
A. VMRD’s competitive enzyme-linked immunosorbent assay (cELISA) detects antibodies to caprine arthritis encephalitis virus in goat sera. The CAE cELISA test utilizes a proprietary xeno-monoclonal antibody derived by fusion of goat splenocytes and mouse myeloma cells which has excellent characteristics for us in cELISA. This antibody is conjugated to horseradish peroxide and is used to compete with serum antibodies for antigen bound to the microtiter plate.
Q. How often should a producer test for CAE?
A. It is important that producers understand that the CAE test is a "snapshot in time" and that the CAE virus can lay dormant for months or years before it begins to reproduce and become infectious. Therefore routine testing is important if you want to maintain your herd as CAE negative. It is recommended that all animals be tested every 6 months.
Q. When should goats be tested for CAE?
A. Marginal result can be an indication of a recent CAE exposure as antibodies are building up in the serum, or this may be the result of a false positive, possibly from the presence of non-CAE antibodies which can interfere with the test. We suggest you wait for 6 – 8 weeks after any vaccinations, injuries or illness symptoms are gone and resubmit for a confirmation.
Kids less than 6 - 9 months old may test positive for CAE if they have received heat-treated colostrum containing CAE antibodies. We suggest retesting these kids after nine months of age to determine their true status.
Q. What is the accuracy of the cELISA CAEV test?
A. Field research has shown that the VMRD CAE test has a sensitivity of 100% and specificity of 99.6%.
Q. How much does cELISA test cost?
A. The test cost differs by the laboratory that processes it and does not include the cost of a sample tube and needle.
Q. How long does it take to receive the test results?
A. The test is run weekly with the results coming out on late afternoon the same day. If you want pregnancy testing run on the same sample, send the samples in on the goat pregnancy submission form and check the "added test" box. If you want CAE only, use the CAE submission form. Results are phoned, faxed or e-mailed to the producer.
Q. What are the advantages of using the cELISA test versus other methods of testing for caprine arthritis encephalitis ?
A. The cELISA’s performance was compared to gp135/90 SU/TM protein immu¬noprecipitation (IP) which is considered the gold standard for detection of antibodies to CAEV viral antigens. Two hundred goat sera collected from the United States were tested by IP and the cELISA. Sensitivity and specificity of the cELISA against IP were 100% and 96.4%, respectively. To analyze the possibility that the cELISA was more sensitive and not less specific than IP, sequential sera from eight experimentally-infected goats were tested by both assays. The cELISA detected antibody in seven of the eight goats before IP, indicating that it is more sensitive than IP.
A field study was carried out by three independent university-associated veterinary diagnostic laboratories located in the eastern, central and western areas of the United States. Four hundred sixteen samples obtained by the participating laboratories were tested by these laboratories with the cELISA and compared to results from a USDA-licensed agar gel immunodiffusion (AGID). Dis¬correlates were refereed by IP.
Against AGID, the cELISA had 14 false negatives and 20 false positives. Twenty-four of these samples had sufficient volume for IP analysis. Immunoprecipitation results agreed with the cELISA on 23 of the samples. The single sample agreeing with AGID was a negative, but remember that the cELISA was more sensitive than IP on the experimental infections.
Q. How should blood samples be prepared and shipped?
A. Farm personnel need to draw blood samples from the jugular vein, which is an easy-to-learn procedure. Blood samples of at least 2 cc’s per animal should be collected in individual vacuum tubes and labeled with each animal’s identification number. It is important to draw samples using individual, disposable needles, to avoid cross-contamination between animals. Needles and tubes can be obtained from veterinarians or veterinarian supply companies.
Tubes containing blood samples should not be opened and should be packed in a well-padded box to avoid breakage. They do NOT need to be packaged in ice. Samples may stay in transit for several days without compromising the results of the test. Fastest results, however, are achieved when samples are shipped via Federal Express, UPS overnight, U.S. postal service overnight, or other overnight carrier method. Less expensive second or third day promise of delivery is reliable for most carriers.
Q. How can a producer get started using the CAE test?
A. Animal managers should contact BioTracking LLC or one of the BioPRYN affiliate laboratories , that offer CAE tesing, by phone (208-882-9736) or email (email@example.com). The Lab will then set up an account, provide detailed shipping instructions and establish a system for returning results to the farm.
Q. To whom is the test available?
A. Thanks to the availability of efficient shipping methods, BioTracking LLC can process samples from farms throughout the United States. Veterinarians or others who serve smaller farms also may wish to regularly pool samples from several farms and ship them for processing.
Q. Where can I find more information about the CAE test?
A. To learn more about the CAEV test, contact BioTracking, LLC or one of the BioPRYN affiliate laboratories
Additional information on CAE can be found at the following website: http://www.goats4h.com/CAE.html