Laboratory Services

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Further information

Lungworm testing

When a Baermann test is used it is crucial that faeces samples are refrigerated and processed rapidly to lower the chances of a false-negative test. Sixty percent of L1 larvae in faeces die within 24 hours at room temperature and 80% or more within 48 hours. False positives can also occur if gastrointestinal nematodes hatch into L1 larvae due to faeces being left for a long time.

Confirming the presence of Dictyocaulus viviparous is known to be challenging even when clinical signs are present in a herd.  Clinical signs start from day 15 of infection whilst the Baermann and ELISA tests are only sensitive from day 23 to day 28 onwards. According to some sources, individual Baermann tests need to be done on 9 heifers or 15 cows to be 95% confident that lungworm is not present in the herd.

Further information on diagnosis and control can be found in the In Practice article by McLeonard and Van Dijk (2017).

McLeonard, C. and van Dijk, J. (2017), Controlling lungworm disease (husk) in dairy cattle. In Practice, 39: 408-419. https://doi.org/10.1136/inp.j4038

Information about the Sheep Scab ELISA developed by the Moredun Research Institute (MRI)

• MRI worked on the test for 15yrs and continue to develop it
• WVSC can now offer the test commercially having spent 18 months validating it at WVSC with MRI
• The ELISA detects ovine IgG binding to recombinant Psoroptes ovis Pso o 2 (rPso o 2)
• As an IgG test, it can be a quick/early diagnosis, but antibodies remain in circulation for a while (3-6 months in circulation after successful treatment)
• Levels do drop significantly after successful treatment, possibly as early as two weeks and much further after four weeks.
• The recommendation in practice is, therefore, to wait a minimum of four weeks before re-testing a group and comparing to the pre-treatment results, but to bear in mind that levels will not be back to baseline levels until 3-6 months later.

For more information on the test, how to use it and Sheep Scab in general please follow the following links:

Useful Sheep Scab Links:

Moredun Flyer – Sheep Scab blood test

Moredun Information on Sheep Scab including links to some useful cartoons

SCOPS Sheep Scab including diagnosis, treatment and quarantine (also useful downloads)