Cheap Dipstick Can Detect Foot and Mouth Disease

A dipstick that can test for foot and mouth disease has been developed by Chinese scientists, who say it is the first for the disease.

Foot and mouth is a highly contagious animal disease caused by a virus. It leads to severe weight loss in cloven-hoofed animals such as pigs, cattle and sheep and is considered the most economically threatening livestock disease worldwide. It does not affect humans.

The test consists of a strip which, when it comes into contact with pig's blood detects a particular antibody that the pig produces as a response to infection with the disease.

"We also tested sheep, cow and guinea pig sera using this strip — they gave positive results," said lead researcher Suzhen Yang of the College of Veterinary Medicine at Henan Agricultural University in China.

"The successful development of the strip has not only provided a rapid, specific, sensitive and simple antibody detection method, but also established a new and practical instrument for animal disease antibodies monitoring," Yang said, adding that it is much cheaper than other methods.

However, critics pointed out that the test fails to differentiate between animals producing the antibody because they are infected, and those that do so because they have been vaccinated. Also, it can only detect one of seven different virus serotypes — serotype O.

"A dipstick test for antibodies to serotype O could be of value for foot and mouth disease control in endemic countries," said David Paton, Foot and Mouth Disease Programme Leader at the UK-based Institute for Animal Health.

However, he said that a test that detects the virus that causes the disease, rather than one that detects antibodies to it, is of "primary importance".

"For large scale surveys of vaccine induced immunity, lab-based serology is more appropriate. However, tests on individual animals prior to sale or movement could benefit from a simple, pen-side technique.

He said the test might be more useful for assessing the efficacy of vaccination programmes.

The study was published in Journal of Virological Methods (2 May)

Source: SciDev net
Date: May 19, 2010