DISEASES AND PARASITES OF MAMMALS 89 



erly. 2 The Texas tick-fever, against which quarantine has long been 

 maintained by some states, is also very serious. Mitchell states that the 

 suppression of the foot-and-mouth disease in 1914-1915 required the 

 destruction of 168,158 head of live stock, valued at $5,676,000. It is 

 difficult to compute or even estimate the large loss from minor diseases 

 that affect all sorts of domesticated animals, reducing their efficiency or 

 otherwise lessening their value. Angora goats are subject to the usual 

 sheep and cattle diseases and to many parasites. In 1880 an epidemic 

 of pleuro-pneumonia nearly destroyed the Angora goat and mohair in- 

 dustry of South Africa, with a loss of 40,000 goats before it was 

 checked. 3 The annual loss in Scotland from domestic animal diseases is 

 placed at nearly $5,000,000, and it is said to be four times as much in 

 England and Wales. 4 



In 1912 about two hundred species of insect enemies of domestic 

 stock were known. 5 Some of them cause the death of the animals they 

 attack, others, though not fatal in their attacks, annoy, weaken and 

 otherwise damage the stock. "Ticks and mites are among the fore- 

 most enemies of domestic animals" (Bishopp). For example, the North 

 American cattle tick transmits splenic or Texas fever among cattle and 

 one species of mite produces sheep scab, while another is responsible 

 for mange in cattle. 



Various species of gnats and flies are very troublesome to both 

 domestic and wild mammals, some of them, in addition to direct at- 

 tacks, being carriers of serious disorders. The damage caused by the 

 ox-bot, or heel-fly, alone has been estimated at $173,596,895 in I9OO. 6 

 Screwworms, tapeworms, lungworms, liver flukes, lice and many other 

 invertebrate pests are named among the enemies of the stock-grower. 

 A calendar showing what pests to guard against during the different 

 months has been recently issued. 7 



It has been mentioned that better methods of combating and pre- 

 venting disease have reduced the hazards of hog-raising. Various other 

 examples are known. For instance, in 1903, eighteen states were 



2 See Hess, Less cholera more hogs, Yearbook U. S. Dept. Agric. for 1918, 

 pp. 191-194. 



8 Angora goat and mohair industry, Interdepartmental Committee of U. S. Dept. 

 Agric. and Dept. Commerce, Miscell. Circular No. 50, p. n, 1929. 



4 Loss from animal diseases, Science, LV, 507, 1922. 



6 Bishopp, Some important insect enemies of live stock in the United States, 

 Yearbook U. S. Dept. Agric. for 1912, pp. 383-396. 



6 Bishopp, ibid., p. 388. 



7 Hall, A calendar of livestock parasites, U. S. Dept. Agric. Miscell. Pub. No. 25, 

 1928. 



