PREVENTIVE MEDICINE 289 



has been present with the exception of the years 1909 and 1917. 

 In 1912 there were 83 outbreaks. 



It will thus be noted that the striking fact with regard to 

 foot-and-mouth disease in this country is its great liability to appear 

 in spite of the stringent regulations which are in operation to 

 prevent its introduction. Another point which is common to nearly 

 all outbreaks in this country, and in any country to which the disease 

 is normally exotic, is that it is often impossible to say how the con- 

 tagium has been introduced. It can certainly be said to be by 

 mediate methods, and it has been remarked that outbreaks here 

 usually coincide with a rise in the prevalence of the disease in 

 continental countries. The Departmental Committee appointed 

 in 1911 gave special consideration to the means by which the disease 

 is imported into the United Kingdom. They considered that " any 

 imports such as hides, &c., which may have formed part of an in- 

 fected animal or been exposed to infection, and other goods such 

 as grain, food-stuffs, &c., which may have been in contact with them 

 must be considered dangerous if such articles are subsequently 

 brought into contact with susceptible animals in this country." 

 They observed that the risk was greater with certain articles, es- 

 pecially hay and straw, milk and milk products, hides and skins, 

 carcases of calves in skins, heads and feet, vaccine seed lymph, hoofs, 

 horns, bone and other animal offals, persons and their clothing. 

 The importation of hay and straw from all other countries, except 

 those scheduled as being free from the disease, is now prohibited, 

 but hay and straw used as packing is a likely mode of introduction, 

 especially as such material usually finds its way into manure. The 

 chief danger attaching to milk is the possible infection of pigs. 

 From hides and skins the danger is that such may contaminate 

 feeding-stuffs either in the ship or in railway trucks, &c., or through 

 the clothing of those unloading the ship. The possibility of sea- 

 crossing birds carrying infection from the Continent to this country 

 on their feet, or in their intestines after feeding on infected animals, 

 is recognised. The disease spreads very rapidly once its introduc- 

 tion has taken place, chiefly by contact between animals, the virus 

 probably entering abrasions, e.g., of the intestinal tract. 



Mediate methods are very largely responsible for the spread 

 of foot-and-mouth disease, and these may be many and varied. The 

 infection may be carried on the hands, clothes and boots of persons, 

 by litter, dung or ships' fittings, birds, dogs, and other animals. The 

 contagium is not air borne, except in so far that a high wind may 

 blow saliva a very considerable distance. Water-troughs or ponds 

 from which diseased animals have drunk are dangerous distributors, 

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