Report of the Departmental Committee on Foot-and-Mouth Disease, 1952-1954.

  • Great Britain. Ministry of Agriculture and Fisheries. Committee on Foot and Mouth Disease.
Date:
[1954]
Catalogue details

Licence: Public Domain Mark

Credit: Report of the Departmental Committee on Foot-and-Mouth Disease, 1952-1954. Source: Wellcome Collection.

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    animal and on any material contaminated externally. Experiments at Pir- bright have shown that the virus remains active on hay, for example, for at least 15 weeks.* The possible ways in which it may be introduced into this country were divided by the 1924 Committee into the “ uncontrollable ” and the “controllable”. We shall adopt the same convenient division. Uncontrollable 13. The uncontrollable agents that come under suspicion are now, as they were then. birds and the wind. Birds 14. The possibility that birds may bring the virus to us from the Con- tinent has attracted so much interest that we have added an appendix (Appendix VIII) setting out in detail the evidence given to us on the sub- ject. Here we will only record our conclusions with a brief statement of . the reasons for them. 15. It has been proved that the virus can be carried mechanically by any moving agency. The possibility of its carriage by birds has been demon- strated by small-scale experiments carried out at Pirbright Research Insti- tute. A starling was externally contaminated on the feet and feathers, and the virus was recovered from the bird 91 hours later. These experi- ments also included the infection of some starlings by the mouth, and virus was recovered from their droppings from 10 to 26 hours after ingestion of the contaminated material. But the experiment did not show that star- lings actually contract the disease and multiply the virus. The present evidence is that, if they are carriers, they are purely mechanical ones. 16. It is known that starlings migrate to England in large numbers from countries in Europe where the disease is endemic, that their cruising speed is about 40 miles an hour, and that their numbers have (been increasing in recent years. They could come from an infected farm on the Continent to an English pasture well within the time that virus has been found active on their feet and feathers in artificial conditions. Whether it would survive as long in natural conditions, exposed to the sun, rain and wind, we do not know, but we have no ground for saying it is impossible. 17. There is therefore strong evidence that the starling is a potential carrier. There is no direct evidence that the disease is in fact brought by him; no witness put it any higher than that in some places flocks of starlings had been in the neighbourhood before an outbreak occurred. The case against the starling as an actual carrier rests on circumstantial evidence only ; in the epidemic of 1951-52 primary outbreaks of obscure origin were relatively more frequent within 15 miles of the coast between Lincolnshire and Dorset than elsewhere ; the type of virus was the same as that on the other side of the North Sea and English Channel ; as the epidemic moved south-west along the Continental coast outbreaks followed it on this side: and no other explanation seems as probable. 18. The case against the starling is thus formidable, but it has not been proved. One of our witnesses suggested that a test should be made by arranging for a small herd to be constantly fed and grazed beside a * We have been told of an outbreak in the U.S.A. of which no other explanation could be found than that it might have been caused by hay infected a year before during an outbreak at the same farm. A partly-used store of hay had been built up after the first outbreak and the second occurred when the store had been reduced to its original level. 12: