New 15-minute saliva test for Ebola may be big boost in the fight against outbreak

Virus proteins in saliva could indicate infection. US Marine Corps

A new diagnostic test for Ebola that can measure viral proteins in the blood or saliva and give results within 15 minutes is going to be tested in Guinea. The British-led project will determine the effectiveness of the test in samples isolated from patients suspected of having Ebola; the results will be validated against routinely used methods for establishing if there is an Ebola infection.

A 15-minute test for Ebola would be an enormous leap forward for clinicians and public health workers who are still fighting a daily battle to contain the virus – and could prevent it from spreading to other countries.

This encouraging news comes as a new warning was issued by Tony Banbury, the head of the United Nations Mission for Emergency Ebola Response, who said there was still a “huge risk” that Ebola could move to other countries across the globe. As the death toll from the deadly virus approaches almost 7,000 victims, with more than 16,000 current infections, the challenge to contain the virus is still at the forefront of the minds of public health officials in West Africa and across the world.

Current screening methods

Many countries including the US and Canada, the UK, France and Belgium have begun screening passengers who arrive on flights from the West African countries most severely affected with the Ebola virus.

This screening includes a questionnaire, which attempts to identify if contact with an Ebola patient could have occurred – but there are issues with this if someone isn’t truthful or is unaware of contact. Testing for elevated body temperatures in travellers was also used to try and determine which individuals should be forwarded for further diagnostic assessment.

But these screening procedures lack specificity for the Ebola virus and are certainly not 100% effective – someone could be carrying the Ebola virus, for example, without yet showing symptoms.

The new 15-minute test can recognise components of the virus in blood or saliva samples – the viral proteins – from suspected Ebola patients. Other tests tend to require extensive and time-consuming amplification of the viral genome, measuring the growth of the virus in cell cultures, or even quantifying the concentration of antibodies against the virus in a patient’s blood. These methods can take anything from several hours to several days depending on virus and technique.

Notably, the reagents – the substances used in chemical analysis – that are needed to perform the 15-minute test are also stable at room temperature and can be contained in a mobile suitcase laboratory. This means test materials can be transported to remote environments without requiring cold storage, unlike laboratory-based diagnostics which may require constant storage in a fridge.

The research, which is still in pilot stage, is funded by the Wellcome Trust and the Department for International Development, who have also been fast-tracking funding for an Ebola vaccine. It is likely that if it is found to be a robust method of screening for Ebola virus, it could rapidly be rolled out to help with the containment of the current outbreak and allow immediate diagnosis of Ebola patients in remote locations. It could also have significant and fundamental implications for air travellers.

Another test called EbolaCheck is also in development, which would give an indicator of the presence of Ebola in body fluids within 40 minutes.

Outbreaks and airports

It is important to fully consider how else a 15-minute test could be used if the initial trial is validated and shown to be successful. In addition to being used in a remote area involved in an Ebola outbreak, it could also likely have significant implications for how airline passengers are screened across the world. Saliva tests for Ebola could become standard practice at airports with flights arriving from the countries most affected by the virus.

In the event of additional outbreaks, the test could be rapidly deployed at security screening and border-control stations. It is also possible to envisage the test becoming mandatory, but – despite the peace of mind for some – being forced to take a saliva test and wait for 15 minutes while going through security could well be considered highly invasive by many people.

Airport screening aside, there is no doubt that the development of rapid diagnostic tests for any highly pathogenic virus, including Ebola, is key in the fight against deadly emerging infections. Increased speed in diagnosing an infection translates to quicker treatments for those people with the virus and increased safety for those who do not.

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