134 SOME MINUTE ANIMAL PARASITES 



danger on the grouse moor, pheasant preserve, or 

 poultry yard, for any young birds feeding with them 

 or reared by infected foster-mothers, ingest the 

 coccidian oocysts and succumb after a short time. 

 They have been well termed "flying reservoirs of 

 disease." When epidemics occur among young 

 birds, it is always well to examine any old birds 

 associated with them, for the parasite carrier has 

 often been found to be the cause of inexplicable 

 outbreaks among previously healthy stock. 



Another feature worthy of note is that oocysts of 

 Eimeria amum can be swallowed by other birds and 

 pass unharmed through their bodies, only to be 

 voided elsewhere and cause incalculable damage. 

 For instance, a bad outbreak of coccidiosis occurred 

 on a certain farm among the fowls. Some sparrows 

 came to the farmyard for grain, and picked up not 

 only grain, but oocysts of E. amum. Visiting other 

 and healthy yards, the excrement of the sparrows 

 was dropped, and contaminated the ground with 

 oocysts, which naturally were a source of danger, 

 and other outbreaks occurred. Sparrows were shot 

 and examined, and it was shown that they contained 

 oocysts of E. avium, but were not infected thereby. 

 They were, in fact, merely mechanical carriers. 



Pigeons also will gather grain wherever they can, 

 and we have personal knowledge of whole pigeon- 

 cotes that have been exterminated by coccidiosis 

 acquired from an infected poultry-run. In the case 

 of domestic poultry kept under cover, the exclusion 

 of small birds such as sparrows can be secured. It 

 is obvious that the danger from such small birds is 



