BRITAIN must get over its reluctance to 鈥渞ing vaccinate鈥� livestock or risk repeating the carnage of the foot and mouth outbreak that crippled the countryside in 2001. So says a report from the Royal Society, the country鈥檚 top academy of science.
The British government refused to employ the controversial strategy last year as it slaughtered its way through 6 million cows, sheep and pigs in an attempt to bring that epidemic under control. But vaccination, never before used in Britain, should be 鈥渁 major tool of first resort鈥� in the future, the scientists say.
Their recommendation comes in a report published this week which looks at how advances in science and technology are generating new options for keeping the disease at bay. It enthusiastically backs emergency ring vaccinations to contain any disease outbreak. That would mean immediately vaccinating all animals within a certain radius of an infected farm to stop the infection spreading. Many of the scientific and economic arguments used last year against emergency ring vaccination don鈥檛 apply today, says the report.
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One major concern was that infected animals might be mistaken for vaccinated ones and accidentally exported to disease-free countries. But there are now tests that can distinguish vaccinated animals from those carrying the disease. The tests rely on antibodies that recognise proteins used by the live virus to replicate in an infected animal. These proteins, however, are not found in the deactivated vaccine. Synthetic vaccines are also being developed which are even less likely to generate false positives (New 杏吧原创, 11 May 2002, p 12).
鈥淭hese scientific developments in discriminatory tests mark a turning point in foot and mouth disease science,鈥� says the report. And changes to international trade regulations this year make it easier for countries to export meat after using vaccination to halt an outbreak. Meat from vaccinated animals could still be eaten.
Concerns over whether vaccinated animals can still harbour live virus in their throats, and whether a vaccine could be given quickly enough to halt the spread of an outbreak are overstated, says Brian Follett, the biologist who headed the report team.
However, Follett鈥檚 panel rules out the precaution of vaccinating all Britain鈥檚 livestock in advance unless better vaccines become available.
Britain should lead an international research initiative to develop such 鈥渞outine鈥� vaccines (see Table).
The report doesn鈥檛 attribute any direct blame for mishandling of the outbreak, but it does identify institutional failures that must be corrected to avoid such a catastrophe happening again. To stop the disease entering the country in the first place, global, European and national surveillance measures must be stepped up and better coordinated, it says. And if the foot and mouth virus or others that cause livestock diseases such as bluetongue do break through the cordon sanitaire, then Britain should have a contingency plan at the ready, approved beforehand by Parliament. Once a contingency plan has been agreed, it should be tested each year 鈥� and it should be updated every three years to embrace new scientific and economic developments.
Animals on infected farms should still be culled, and the transport of animals should be halted immediately to stop the virus in its tracks, says the report. But better surveillance, especially routine farm visits from vets using new pen-side tests, should enable any outbreak to be spotted much earlier and allow the contingency plan to swing into action immediately.
Most of the panel鈥檚 recommendations are echoed in another report published this week by the Royal Society of Edinburgh. 鈥淭he time has come to change the way we tackle these infectious diseases and adopt more modern procedures,鈥� says Follett.