PCR Sample Collection Advice - Equine

PCR Sample Collection Advice for Equine outlines correct procedures to ensure accurate and contamination-free PCR testing in horses.

Equine Faecal Multiplex PCR Panels

PCR testing of faecal samples allows evaluation for a range ofinfectious organisms in a single test – bacterial, protozoal and viral.For most infectious organisms included in the panel, PCR is themost rapid, sensitive and specific assay method.

The adult equine faecal PCR panel (code AHP) is performed onhorses over 6 months of age and includes Lawsonia intracellularis.

The foal equine faecal PCR panel (code FHP) is performed on horsesless than 6 months of age and includes Rotavirus and Clostridiumperfringens Net F, very recently associated with severe enteritis inyoung foals in Kentucky.

Both panels include Equine Coronavirus, documented as causingoutbreaks of pyrexia, enteric disease sometimes with neurologicaldisease in America and Japan. The status of equine coronavirusinfection in Australia is not known.

The PCR panel does not test for faecal parasites so a McMaster Eggcount should be done separately.

The sample required for PCR testing is a fresh rectal faecal sample(5 grams) collected as early as possible in the disease course. Rectal swabs (PLASTIC white capped swab stores code 601260) can be collected from foals if a quantity of faeces cannot be achieved.Intestinal content samples from areas of affected intestines collected at surgery or post mortem examination can also be used and are likely more reliable in confirming infections particularly in adults.Pool multiple sites. Place the sample in a sterile container and refrigerate as soon as possible.

If other faecal tests are additionally required (including faecal eggcount or culture), a separate faecal sample in a sterile container will need to be submitted.

Equine Respiratory PCR Panel – code RPE

Sampling should be performed as early in the disease course as possible. Increased chronicity, previous treatment and prior vaccination can reduce the detection of organisms. Latent infection of Herpes virus cannot be detected by PCR as the virus is sequestered in nerve ganglions and is not present on the epithelium.

The best samples for Equine Respiratory PCR contain large numbers of epithelial cells with minimal other material. Nasal or nasopharyngeal swabs, guttural pouch lavage or tracheal aspirations can all be used.

Use sterile swabs without wooden shafts to collect samples. White capped swabs with plastic shafts are available from stores code 601260. Use the same swab to firmly run along the nasal planum or the nasopharynx of both nasal cavities with a minimum 20secs contact time on both sides. Place wash or lavage fluids in a sterile container (10ml sterile graduated yellow screw top centrifuge tube stores code 646808). Label the container or swab and keep the samples refrigerated prior to sending to the laboratory for testing.

If swab culture is also required, please submit a separate swab in bacterial transport media (blue capped from stores). If cytology is also required for tracheal washes, please submit a separate EDTA fluid and slides.

Faecal Salmonella PCR – code SAL

Faecal salmonella PCR is also offered as a standalone test.

The sample required for PCR testing is a fresh rectal faecal sample (5 grams) collected as early as possible in the disease course. Rectal swabs (PLASTIC shaft only) can be collected from foals if a quantity of faeces cannot be achieved. Intestinal content samples from areas of affected intestines collected at surgery or post mortem examination can also be used and are likely more reliable in confirming infections particularly in adults. Pool multiple sites. Place the sample in a sterile container and refrigerate as soon as possible. White capped swabs are available from stores code 601260.

To detect shedder horses, collect 2 to 4 fresh faecal samples (5 grams) 12 to 24 hrs apart. Keep samples refrigerated until all samples are collected and submit on the one request form. Volume discounts are available for multiple tests on the same animal submitted at the same time. Speak with a veterinary pathologist at Vetnostics.