Video transcript: Foot-and-mouth disease: controlling outbreaks

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May 2011

Dr Bryan Charleston, Institute for Animal Health
Our recent research with foot-and-mouth disease virus to understand when transmission occurs between cattle have identified that the period of infectiousness is much shorter than we realised. And also, most importantly, the animals are not infectious before they show clinical signs. Previously, using measures such as virus in blood, or virus in saliva, or other bodily fluids, it was suggested that animals were infectious before clinical signs and that they were infectious for a much longer period. Now when you put those numbers about when animals became infectious and how long they are infectious into large scale models, to show spread between cattle and between herds, you get a quite different result than we would get by using our information where we've actually looked at transmission. So what we did is we mixed infected animals with non-infected animals at different time points during the course of infection and, as I say, from that we've shown that the animals are not infectious or unlikely to be infectious before clinical signs, and also, they are only infectious for approximately two days. So this will allow us to target our control measures more specifically.

Our research on foot-and-mouth disease also indicates where we can improve control measures by the development of new technologies. The major one would be the development of sensitive diagnostic tests to pick up the virus in animals before they show clinical signs. So this would be an early warning that the animals were going to become infectious and we can apply control measures before they become infectious.

During the 2007 outbreak of foot-and-mouth disease virus, attempts were used to carry out this pre-clinical diagnosis in herds that were close to animals that had been infected. And by routinely blood sampling those animals, and carrying out sensitive diagnostic tests in a laboratory, we are able to reduce the number of animals pre-emptively culled because they never became infectious, so there was no need to cull them.

So in the 2001 outbreak of foot-and-mouth-disease virus in the UK we could see the devastating effect it had on whole areas of society. This is a virus that can essentially bring the country to a halt, effect tourism, huge financial losses, and most importantly, effect the livelihood of the farming population. Some of these farming communities have bred livestock over many generations for many years and to have those animals culled goes beyond the financial implications of the disease.

We're all aware of the outbreaks of foot-and-mouth disease in the UK in 2001 and 2007, but foot-and-mouth disease is a problem worldwide everyday of the year. Controlling foot-and-mouth disease also will have a big impact on food security by improving the productivity, both in countries that have infection coming into their country when they were previously free of the virus, or if they are dealing with the virus everyday in an endemic situation. So by improving the health and welfare of these animals will improve the food supply chain for all of us.