A diagnostic test that can detect whether an animal has been infected by or vaccinated against any type of foot-and-mouth disease virus (FMDV) has been developed by scientists at The Pirbright Institute and Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna (IZSLER). The test could be used in countries where foot-and-mouth disease (FMD) outbreaks are continuous, in FMD free countries or at borders to rapidly and easily identify an animal’s disease status, which is crucial for trade and outbreak control.
FMD is a viral disease that affects cloven hoofed animals such as cattle, sheep, goats and pigs, which incurs large economic costs and constrains international trade of animals and animal products. The virus exists as seven different types, called serotypes, each of which come in multiple strains. When an animal is vaccinated or becomes infected with FMD, the animal’s immune system generates many different antibodies, each one binding to specific parts of the virus.
This new test provides a single ‘yes/no’ reading as to whether a sample contains a specific antibody against FMDV particles. If the result is positive this indicates the animal has either generated these antibodies in response to a natural infection or a vaccine.
Current FMD antibody tests for detection of infected or vaccinated animals are only able to detect antibodies that are unique to each serotype (though they may suffer some inter-types cross-reactivity), meaning that a test for one serotype will not confirm if an animal has been infected by a different serotype. Therefore, multiple tests may be needed in order to establish the disease status of an animal. Not only that, each test requires different reagents to work, making the testing process less efficient and more resource intensive.
To overcome these limitations, the team developed a diagnostic test that is able to detect antibodies which bind to a protein that is present across all FMDV strains. If the antibody is detected by the test, this will indicate the animal has been exposed to an infectious or vaccine strain of the virus, regardless of the serotype.
In a study published in the Journal of Clinical Microbiology, the team demonstrated that the new diagnostic test detected antibodies from serum samples of infected and vaccinated cattle with equivalent or improved sensitivity compared to existing tests. Although low cost, rapid and efficient, the test will not replace current diagnostics as it is important to identify the individual FMD serotypes for surveillance and control purposes.
“This new diagnostic test will provide a quick initial test that can be used in countries where this disease is present particularly at borders where the disease status of animal imports needs to be established, or for surveillance during outbreaks in countries that were previously FMD free” explained Dr Amin Asfor, lead author of the study. “The new test could also be used to complement or confirm outcomes of the currently available diagnostics,” he added.
The next step will be to validate the test for commercialisation by ensuring it works for multiple susceptible animals in different countries. A recent grant from the Biotechnology and Biological Science Research Council (BBSRC), part of UK Research and Innovation (UKRI), will enable scientists from Pirbright to travel to countries where FMD is circulating in order to evaluate the new diagnostic test in outbreak situations.
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Post time: Oct-09-2020