278 



CALIFORNIA FISH AND GAME 



foot-and-mouth disease. The last deer showing old lesions was killed 

 on September 12, 1925, and all quarantine was removed on June 10, 

 1926. Perhaps the most important lesson to be learned from this 

 tragic experience is that such infectious diseases are similar to forest 

 fires. Prevention is much better than cure, and where an outbreak 

 or fire does occur it should be controlled promptly while still in the 

 "ten-acre" class. 



INTERNAL PARASITES 



Internal parasites such as lung worms, round worms and tape 

 worms, cause considerable loss of mule deer in California at certain 

 times when climatic and other conditions engender a heavy infestation 

 of such parasites among the deer. As regards ordinary conditions when 



Fig. 107. California mule deer doe protecting: her nose from attack of deer 

 bot fly. Note position of nose between hind leg and body. Yosemite June 20, 1927. 

 Mus. Vert. Zool. No. 5416. 



the deer are in good physical condition and well scattered over the 

 entire range losses from this source are relatively small, but when the 

 deer are in poor flesh and are concentrated on limited areas as some- 

 times occurs on winter range during heavy snowy winters, then losses 

 from internal parasites may become acute. These parasites usually 

 kill indirectly by so weakening the deer tliat during the stress of a hard 

 winter such infected deer frequently die off through exposure and cold 

 or become so weak that they are easily captured by predators. In 

 California the most serious infection of lung worms noted among deer 

 has occurred in the Columbian black-tailed deer in the Trinity region. 

 In my experience with deer in California, I have found the various 

 races of mule deer to be relatively free from this disease. Now and 



