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Johne's Disease

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Informational handouts on Johne's Disease 

Powerpoint presentations available for download

 Direct Fecal PCR Mycobacterium paratuberculosis

The ISU VDL is approved to perform qualitative direct fecal PCR testing for the detection of Mycobacterium avium var paratuberculosis DNA in bovine feces.  Results are available in 3-5 days compared with the eight weeks required for liquid fecal culture testing. Sensitivity for the direct PCR is comparable to the culture system for high- and moderate-shedding animals. The test is also highly specific for detecting MAP DNA and is able to discriminate between Mycobacterium avium var paratuberculosis and other fecal Mycobacteria species.

Collect feces directly from the rectum if possible. Place at least 2 grams (1 tablespoon) into sterile plastic container. Use permanent marker to label vial with animal ID. Submit cooled samples to the ISU VDL as soon as possible. Do not freeze.

For more information, contact Dr. Tim Frana at tfrana@iastate.edu or 515-294-1950.

Pooled Fecal PCR Mycobacterium paratuberculosis

ISU VDL offers a pooled fecal PCR test for Johne’s Disease diagnosis in cattle. The test is run similarly to the direct fecal PCR, but will allow pooling of up to 5 fecal samples with results available in 3-5 days. This can reduce testing costs and increase choices in testing strategies. If a pool is positive, testing of individual samples with PCR or culture can be performed.

Sample collection from individual animals is the same as the direct fecal PCR. Collect feces directly from the rectum if possible. Place at least 2 grams (1 tablespoon) into sterile plastic container. Use permanent marker to label vial with animal ID. Submit cooled samples to the ISU VDL as soon as possible. Do not freeze or pool the samples. POOLING PROCEDURES WILL BE DONE AT THE VDL.

For more information contact Dr. Tim Frana at tfrana@iastate.edu or 515-294-1950.

Liquid Culture test

To provide the highest level of service and utilize cutting-edge technology, the ISU VDL has expanded its testing capabilities to provide quicker detection of animals that represent the highest risk to herd mates Mycobacterium avium var paratuberculosis (MAP), the causative agent of Johne's Disease, is difficult to detect due to sub-clinically infected animals and the slow growth of the bacterium. Fecal testing for MAP is still considered the gold-standard of diagnosis, with fecal-positive individuals classified as low, medium, high, and even super shedders. Super-shedders can look clinically normal but shed as many bacteria as 20,000 low-shedding animals (Whitlock, et. al., JDIP Annual Proceedings, 2006) USDA estimates that MAP-infected cattle cost producers from $200 to $900 per animal per year.

The ISU VDL is now offering the Trek ESP liquid culture testing system for the detection of MAP in feces.  MAP colonies are detected in the broth using automated technology.

The ESP system provides faster turnaround time as heavy shedders are frequently identified in 1-2 weeks. Maximum incubation time for negative samples with liquid media is 7-8 weeks, compared to 16 weeks when using solid media.

Sensitivity and specificity of the liquid culture system and the solid culture method are equivalent, so accuracy is not compromised by using the more rapid method.

Positive cultures detected by the TREK instrument are confirmed as MAP by acid-fast staining and PCR testing.

The initial validation of this system is complete and the results have surpassed expectations.  While internal validation continues, samples will be run on both systems to ensure the highest quality results.

The Iowa Department of Agriculture and Land Stewardship (IDALS) recently began participating in the National Johne's Disease Control Program, which provides guidelines for detecting infected animals and minimizing risks to herd mates through management practices.  The goal of Voluntary Johne's Disease Program is to certify Johne's negative herds according to the USDA definitions.  IDALS has funding to subsidize producers' lab fees and veterinary participation in risk assessment.   Participation in the program is completely voluntary and the confidentiality of test results will be maintained within the limits of Iowa law.  For more information, please contact Dr. Eiben, Iowa Johne's Disease Coordinator, (IDALS), at 515-281-0866 or your state district veterinarian.

Guidelines for Fecal Collection and Submission

For animals tested under the IDALS State Johne's Program, use the Iowa Johne's Program submission form as provided by IDALS for subsidized testing. 

For non-program submissions, use the ISU VDL serum submission form (even if fecal samples are submitted), be sure to include animal number, age, and production class (i.e. stage of lactation). Test results are most accurate if samples are not frozen.  For submission of more than 10 samples, please call the ISU VDL to schedule a submission date.  Tests are run on Monday, Tuesday, and Wednesday, so samples arriving on these days will be processed on the same day.

Collect fecal samples directly from rectum (unless doing environmental sampling).  Do not collect ground or floor samples.  Use a separate, dry glove to collect individual sample (moisture and lube may adversely affect the pH of the sample). Place a minimum of 5-10 grams (1/2 ounce or 1 tablespoon) into sterile, plastic container (rectal sleeves and gloves will not work).  We recommend Fisher brand Polystyrene Sample Vials (catalog # 03-341-13) or similar containers for submissions. Use permanent ink to label container with animal ID and premise ID if available. Place container in cooler with cold packs so samples will cool quickly.  Transfer samples to refrigerator ASAP.  Do not freeze in commercial freezer.  Include ice packs to keep samples cool during shipping.  Samples must be processed within 96 hours of collection or frozen to -70ºC at the laboratory for later processing. For fecal pooling, five individual animals of similar ages/lactations will be combined in a pool.  POOLING PROCEDURES WILL BE DONE AT THE VDL. 

Submission forms should contain ID numbers and ages for all animals. Please feel free to contact Dr. Tim Frana at tfrana@iastate.edu or 515-294-3861 with questions.

ISU LINKS

 

VDL Johnes testing

VDL Submission Form


ISU Dairy Resources

FSVM Dairy Extension

OTHER LINKS

 

Johne's Disease Integrated Program

Johne's Info Central

U of WI Johne's Information Center