"GROUSE DISEASE " COCCIDIOSIS 261 



the epithelium of the gut may be able to recover itself, when the bird gradually 

 increases in weight and makes partial or entire recovery. This recovery is some- 

 times aided by infiltration of connective tissue into the lesions. If, however, the 

 infection has been heavy, the epithelium cannot regenerate itself, and the bird 

 becomes exhausted and dies. 



V. RELATIVE RESISTANCE OF DIFFERENT BREEDS OF FOWLS AND PIGEONS 



TO COCCIDIOSIS. 



Young chicks are far more susceptible to Coccidiosis than adult birds. 1 Very 

 young fowl chicks (up to eight days old) die in a few days after being fed with 

 coccidian oocysts. Chicks first dosed with cysts when fourteen days old do not 

 succumb so readily ; they may live for some weeks, or some may become chronics, 

 when daily examination of their faeces shows periodic small crops of oocysts. 



Older chicks are more likely to recover from Coccidiosis. For example, a 

 Grouse chick aged thirteen weeks was fed on oocysts, and when killed three weeks 

 later very few Coccidia were observed. Again, a young Grouse which had been 

 picked up dead on the moors in Inverness-shire was received on September 15th r 

 1909. In its caeca numbers of both coccidian oocysts and Trichostrongylus pergracilis 

 were found. The bird had probably survived an attack of Coccidiosis and in its 

 weakened condition had fallen a victim to Strongylosis. 



Different breeds of fowls have varying powers of resisting Coccidiosis. Pure- 

 bred Leghorn and Minorca chicks died from the disease in a comparatively short 

 time. Plymouth Rock chicks were attacked quickly, but had greater resisting 

 powers than pure Leghorns or Minorcas. Cross-bred Leghorns were far more 

 resistant to the disease than the pure-bred birds. 



Regarding pigeons, Fantails are more susceptible than the ordinary pigeons, 

 though squabs of any variety seem easily attacked and overcome by Coccidiosis. 



VI. THE DISSEMINATION OF COCCIDIOSIS OVER TRACTS OF COUNTRY. 



Coccidiosis outbreaks spread with fair rapidity, but though many birds in one 

 locality become diseased, adjoining estates may be free. Epizootics of Coccidiosis 

 also disappear very quickly. 



Infection has been shown experimentally to be due to the ingestion of oocysts 

 (cysts), either by way of the food or drink. Coccidian cysts may occur on the 



1 Old birds may become chronics and thus infect the moors. In this connection infected foster-mothers 

 in Pheasant-rearing may be dangerous. 



