Virology
General Information
Ear Notch Submissions
Submission Guidelines for Virology
Sample selection, as well as proper collecting and handling of samples, is of critical importance prior to the submission of samples for virology. Please consider the following points.
  • Please complete a CF.369 Regular Submission Form or CF.392 Neoplasm Submission Form and submit with sample. Forms are available on the Forms page.
  • Appropriate samples should be selected after the probable diagnoses have been considered. See manual for a listing of suggested specimens for each virus. If your virus of choice is not listed in this guide, please call the ADDL for instructions.
  • Swabs, fecals, or tissue samples taken as aseptically as possible from animals in the early stages of clinical disease are best. Most viral infections are cleared approximately 5 days after onset of signs.
  • Postmortem samples should be taken immediately after the animal has died. Organ tissues, to be evaluated separately, should be taken aseptically and packaged individually in plastic bags. Segments of gastrointestinal tract (2-4" segments) should be submitted intact (unopened) and tied off with string or twine. Intestines or contents should not be placed in the same plastic bag as organ tissues. Additional tissue is required when more than one examination (e.g., VI, FATS, EM) is requested.
  • Selection of the area of larger organs, such as lung, liver, and brain, is often important. In tissue with marked changes, higher levels of virus are generally found at the active edge of a lesion. Necrotic centers of lesions or areas of normal tissue are often non-productive specimens for isolation.
  • Fecals preserved with one (1) part formalin to nine (9) parts feces are examined by electron microscopy for viral particles. Fresh, chilled fecals can be processed for viral isolation and/or electron microscopy. Do not freeze materials to be examined by electron microscopy.
  • Samples should arrive in the laboratory as quickly as possible in a chilled state (32-34°F). Insulated containers with ice packs are suitable for this purpose. Avoid fluctuating temperatures and slow freezing. The level of virus in tissue (when it arrives at the laboratory) is always less than at the time of collection.
  • Pertinent information concerning history, premise ID, herd size, owner's name, numbers and ages of animals involved, vaccinations, etc., should accompany the samples on CF.369 Regular Submission Form. When possible, be specific as to the types of viral examinations being requested to avoid unnecessary charges.
  • Please notify the Virology Laboratory 24-48 hours prior to submitting large numbers (>20) simultaneously.
Submitting Ear Notches for Persistently Infected Bovine Viral Diarrhea (BVD)
Bovine viral diarrhea virus (BVDV) belongs to the family Flaviviridae, the genus pestiviruses. There are several members of the genus and two types of BVD viruses. All of them are highly infectious and of economic importance to the livestock industry. If a fetus becomes infected in utero with BVD virus in the early stages of pregnancy, the newborn calf will become persistently infected (PI) without immune response to this virus for the rest of its life and will shed BVD virus in the herd, infecting other animals. If a PI animal is not identified in the herd, it will be a source of infection. Elimination of BVD from the herd requires removing PI animals.
There are several assays available to identify PI animals: Polymerase chain reaction (PCR), virus isolation (VI), immunohistochemistry (IHC), and antigen-capturing (Agc) ELISA. The AgcELISA is a rapid diagnostic tool that can identify PI animals in the herd. Serum and ear notch samples are suitable for PI animal testing by AgcELISA for BVD viral antigen. To provide optimum service on this assay, the following guidelines should be followed when sending ear notch samples to ADDL:
  • Ear notches should be taken with a sharp ear notching tool suitable for adult swine.
    • Baby pig ear notches, punches, and other cutting and punching tools are NOT recommended; the sample they provide is too small for an accurate test.
    • Dull notches can damage animals and samples are not sufficient.
  • Ear notches must be fresh and the samples must be approximately 1cm x 1cm (3/4 x 3/4 inches) in size.
    • Avoid testing scabby or frostbitten ears.
    • DO NOT put samples in formalin.
    • Samples should be submitted fresh and chilled. For short-term storage (1-2 days), samples can be refrigerated at 39°F; for long-term storage, samples can be stored at -4°F or colder.
  • Package individually in snap cap tubes (12x75 mm). These can be obtained from the following vendors: Fisher Scientific at www.fishersci.com (catalog #14-959-2A) or VWR at www.vwrsp.com (catalog #60818-419).
    • DO NOT use Whirl Pak bags to submit samples.
    • Number tubes 1,2,3, etc., with animal identification to match information on accession form. Numbers should be clearly marked and legible.
    • If submitting more than 200 ear notches, please call the ADDL prior to submission to allow for the quickest possible processing and reporting of samples.
  • A PCR test for pools of up to 25 ear notch or serum samples is available. If the pooled sample is positive, ear notches or serum samples in that pool will be re-tested individually by antigen capture ELISA. Submit individual fresh samples in 5 ml sterile snap cap tubes, labeled with the animal identification, and a completed ADDL submission form. Specify that you are requesting the pooled BVD PCR.
Samples will be pooled at ADDL.
It is strongly recommended that ear notchers be disinfected in 10% bleach after each sample is collected. Do not vaccinate or tattoo animals at the same time ear notches are taken.