Taking a Rectal Biopsy for testing in RT-QuIC
During sample collection, animals should be restrained using a conventional large animal squeeze chute. Rectal biopsies should be collected using sterile, single use instruments by removing a 0.5 cm × 0.5 piece of superficial mucosal tissue from the wall of the rectum, approximately 2 cm ad-oral from the mucocutaneous junction of the anus as in Haley et al 2018. The tissue should be placed into a 1.5 ml microcentrifuge tube and frozen for RT-QuIC analysis. Samples should be shipped with ice packs to maintain cold storage for duration of shipping.
We will send you:
Labeled tubes for sample collection and divided boxes to ship tubes.
An inventory list with space to write down animal numbers/ear tag number to keep track of the order samples are taken.
A cold box and ice pack for shipping samples.
Clean biopsy scissors for our cost.
Keep the inventory sheet and make sure all tubes are in order and you know which number corresponds to which deer/elk.
Ship samples in boxes on ice packs using overnight or 2 day shipping to :
Scrapie RAMALT sampling Veterinary Laboratories Agency, UK
Why a rectal biopsy?
Just inside the anus there is a section of lymphoid tissue that harbors CWD. The tissue is called recto-anal associated lymphoid tissue or RAMALT. Both RAMALT tissue and tonsil have been shown to be sites of early prion replication prior to prions entering the brain (Hoover et al. Journal of Virology 2017).
How much tissue should be taken?
A 0.5 x 0.5 cm piece of tissue is plenty for RT-QuIC testing. More is required for CWD testing by IHC (2 x 2 cm)
How many biopsies can be taken?
Over 13 biopsies have been taken from 1 deer without loss of RT-QuIC positivity.
Why use separate instruments for each animal?
RT-QuIC is a very sensitive test for CWD. CWD prions can stick to metal and potentially transfer CWD seeding activity detected in RT-QuIC from one collected sample to another. As a precaution, we recommend that each sample is collected with a new, unused pair of biopsy scissors. We provide scissors at no mark up to our customers.