Former dairy farmer Jonnie Yewdall joined vets, farmers and others to discuss a new hope of ending the bTB heartache...
By identifying carriers of the disease at a very early stages of infection, Actiphage enables disease management through the removal of these animals from the herd or prior to movement.
It also supports the introduction of a vaccine which would provide the ultimate protection for herds.
Current test of bTB lacks sensitivity
The primary screening test for tuberculosis in cattle is the Single Intradermal Comparative Tuberculin Test (SICTT) – a tuberculin skin test that detects the presence of a mycobacterial immune response in the animal.
For this test, a veterinarian injects a small amount of Avian and Bovine tuberculin into a fold of skin to see if there is an immunologic reaction. If the animal is infected a localised swelling can be detected three days later.
The test is thought to be only 50-60% effective, takes three days to produce a result, requires at least two visits by a vet and cannot distinguish between infected and vaccinated cattle, thus removing vaccination as a potential control mechanism.
Clinical tests are defined by two measures, specificity and sensitivity. The UK Government estimates the accuracy of the SICTT skin test to be:
Therefore, for a herd with a hundred cows infected with bTB, the SICCT test could miss up to 50, leaving behind a reservoir of infection.Another issue is that SICCT measures the immune response of the animal, rather than detecting the presence of the mycobacteria and actual infection. Therefore, the skin test may miss cattle that are in the early stages of infection and have not yet developed a strong immune response to it, and also give a false positive to animals that have been vaccinated.
Greater sensitivity with Actiphage
A survey using Actiphage of 41 SICTT-positive UK cattle tested at slaughter found live M.bovis in the blood of all animals with visible lesions (13/13) and in 93% (26/28) of animals with no visible lesions (NVL) following post-mortem examination.
This study confirms that relative to SICCT, Actiphage has a sensitivity of 95% and a specificity of 100%.
OIE validation
Further laboratory verification work is being undertaken to prepare for validation to World Organisation for Animal Health (OIE) guidelines.
PBD Biotech’s highly sensitive and specific Actiphage assay is included in the Government’s ‘Exceptional private use’ policy for chronic TB breakdowns in England (2018) and in Wales (2019).
PBD Biotech Ltd
Link House, Elm Farm Park,
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Suffolk IP31 3SH,
United Kingdom
Registered Company Address
Ingenuity Centre,
University of Nottingham,
Innovation Park, Triumph Rd,
Nottingham NG7 2TU,
United Kingdom
Health Protection Scotland has launched a consultation on bovine tuberculosis diagnostic testing - but only the skin test? Why not the use of a blood test, pre-movement to keep Scotland OTF status by detecting early infection? @P_H_S_Official @BritishVets
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Read MoreDelighted to be taking our Actiphage tuberculosis blood test to Zambia, in a collaborative project with @ZambartResearch, @LSHTM, @LeicResearch The aim is to test its sensitivity in a real world setting. #Tuberculosis #EndTB #InvestToEndTB
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