17 May 2002

F&Mvaccine hope

SUCCESSFUL trials of a new synthetic foot-and-mouth vaccine may avert the need for mass slaughter in future outbreaks, according to a report in New Scientist.

The vaccine is based on a single protein which resembles part of the virus, says Alan Walfield of United Biomedical, the US company developing the vaccine. "This avoids the problem with existing vaccines consisting of inactivated whole viruses."

Using whole viruses lead to antibodies being produced, making it difficult to distinguish between vaccinated and infected animals. However, animals given the new synthetic vaccine only make antibodies against the protein.

Recent trials in pigs found the vaccine protected 20 out of 21 pigs exposed to the disease, better than conventional vaccines, says Dr Walfield. "The vaccine is now being modified for use with sheep and cattle."

Commenting on these results, the Institute of Animal Healths David Paton based in Surrey, says while these preliminary results are promising, more work is required.

"Issues to be resolved include how long does the response last and does it work with other F&M strains, this preliminary test only involved one strain, and how effective is the vaccine for cattle and sheep."

Current research at the institute is going one step further by developing DNA vaccines. These would work by vaccinating cows with the genetic code for these viral proteins. Animals then produce these proteins, their own vaccine, stimulating an immune response, he explains.

Dr Paton believes that such vaccines would control disease without the problem of identifying carrier animals. &#42