The TrichLabCheck voluntary inter-laboratory comparison project

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The TrichLabCheck voluntary inter-laboratory comparison project

Tritrichomonas foetus causes bovine trichomoniasis, an economically important reproductive disease of cattle. It causes asymptomatic infection in bulls following mating with an infected cow. Trichomoniasis causes temporary infertility or abortions in cows and heifers which results in the loss of the birth of a potential calf. Although the infertility is not permanent, the loss of income for the farmer is considerable and the disease often affects most of the cows and heifers in a herd.

There is currently no effective treatment and vaccination alone does not seem to be an effective means of controlling this disease, therefore a test and cull policy is used to manage infections in cattle herds.

Testing for trichomoniasis is based on a sample taken from the bull to identify the causative organism. The test for trichomoniasis is unfortunately not 100% accurate, and a significant number of positive bulls will give a negative test result if tested only once.

This poor testing accuracy is caused by four possible factors:

  • Biological factors: Bulls do not always yield a sample with sufficient numbers of organisms for a diagnosis, irrespective of the type of test performed. For instance, bulls may test negative during breeding season.
  • Sampling factors: If the sample is not collected correctly, the diagnosis will not be made. It is therefore essential that the sample is taken by a veterinarian.
  • Sample transport factors: If the delivery of samples to the laboratory is delayed, it will lead to false negative results. The veterinarian and laboratory staff must therefore ensure the timely delivery of samples to the laboratory.
  • Laboratory factors: Laboratory processes for the correct identification of T foetus organisms or their DNA in samples is critical to the correct diagnosis of trichomoniasis.

With this project we aim to address the fourth challenge in detecting trichomoniasis in cattle namely the effectiveness of the laboratories performing the tests to accurately identify the organisms in our samples.

Our aim is the validation (not accreditation) of the accuracy of participating laboratories to correctly detect T foetus in standardised, simulated samples through an annual blinded inter-laboratory comparison. Samples sent to laboratories are either moderately or heavily infected, with heavily infected samples serving as positive controls, non-infected samples serving as negative controls and a few duplicate samples to test and compare the laboratories’ accuracy and repeatability in the trichomoniasis test.

Requirements for laboratories to be listed here as being validated for accuracy of their trichomoniasis test results:

  • The laboratory must participate on a voluntary basis.
  • The laboratory must be registered with the South African Veterinary Council or a similar authority to perform tests for the diagnosis of trichomoniasis in South Africa.
  • The laboratory must have achieved an acceptable level of accuracy in the detection of T foetus positive and negative samples.

The following labs have been validated for sensitivity (>90%) and specificity (100%) for the detection of live Tritrichomonas foetus organisms in bull sheath scrape samples during 2020:

 

Lab Name Town/City Province Diagnostic method Contact Details
Capricorn Veterinary Laboratories Polokwane Limpopo PCR leandra@caprivet.co.za
Molecular Diagnostic Services Westville KwaZulu-Natal PCR mikaela@mdsafrica.net
SeroPreg Bloemfontein Free State PCR + Culture ansie.roets@seropreg.com
Trichlab Ermelo Mpumalanga PCR trichlab2@gmail.com
Vriesit Andrology Pretoria Gauteng PCR henk@vriesit.com
Allerton Provincial Veterinary Laboratory Pietermaritzburg KwaZulu-Natal PCR tracy.schmidt@kzndard.gov.za

This project has been supported by the Ruminant Veterinary Association of South Africa (RuVASA), undertaken by the University of Pretoria’s Faculty of Veterinary Science, and supported financially by Red Meat Research and Development South Africa (RMRD-SA)