Blood test delivers TB results in six hours

British researchers have developed a new blood test for TB in cattle which can deliver results within six hours.

The test is used to detect levels of mycobacterium bovis (M bovis), which causes bovine TB, in a cow’s blood.

Developed by a team at Nottingham University, the blood test can deliver results in just six hours and experiments have shown it is more sensitive than the current Single Intradermal Comparative Cervical Tuberculin (SICCT) skin test.

Dr Cath Rees, who led the work, said the team had used a blood testing technique patented by the university to test blood for M bovis, and refined it to deliver results within six hours.

Dr Rees said: “The data we are getting has taken the scientific community by surprise.

“In our paper we show that when blood samples from skin test negative cattle were tested for M bovis cells, all the samples proved negative.

“However using just a 2ml blood sample, viable Mycobacterium tuberculosis complex bacteria (MTC) were detected in 66% of samples from skin test positive animals.

“When the carcasses were inspected, it was found that the highest number of bacteria were detected in the animals with visible TB lesions (VL) and 85% of these VL animals were M bovis positive.

“More excitingly, using our new more sensitive six-hour method, this figure is even higher – all animals with visible lesions were MTC positive, and even 26 out of 28 animals where the lesions were not yet visible also were positive suggesting that M bovis is commonly found in the circulating blood of infected animals.”

She said difficulties in achieving sensitive disease detection with the current skin test, which looks for the animal’s immune response, were a major barrier to understanding and diagnosing TB in cattle.

The new blood test for TB in cattle is licensed to a spin-out company called PBD Biotech Ltd.