CHICKEN-PEST. 



Definition. A deadly form of hsemorrhagic septicaemia caused 

 by an invisible, filtrable microbe, and leading to hyperthermia, 

 great prostration, dullness, stupor and early death with exten- 

 sive petechiation, blood extravasation, and exudation in the bow- 

 els, mucosa, serosse, liver, lungs, spleen, kidneys, etc. 



Synonyms. Chicken typhus ; Chicken typhoid ; Exudative 

 typhus ; Vogelpest ; Birdpest ; Henpest ; Kyanolophia. 



History. Described by Centanni as prevailing in Italy in 1891, 

 this deadly affection extended to the Tyrolean Alps, was found 

 in Brunswick in 1901, and soon in Wurtenberg, Hesse, Belgium, 

 Oldenburg, and North Prussia. 



Cause. That the disease is most virulently contagious has 

 been abundantly proved, and that the germ is self-multiplying is 

 unquestionable, 400. of a solution of virulent blood (1:125.000.- 

 000) proving fatal to a hen of 370 grams, and such successful 

 inoculations from hen to hen for four or more removes losing 

 nothing of the virulence (Maggiora and Valenti). Yet the most 

 careful staining and the highest powers of the microscope have 

 hitherto failed to detect the germ, which passes readily through 

 a Berkefield filter. Maggiora and Valenti failed to pass it through 

 a Chamberland K filter. It is evidently one of the infinitesimal, 

 invisible microbes like those of rabies, lung plague. Rinderpest 

 and Aphthous fever. 



Virulent blood dried at room temperature and kept in the dark, 

 remained virulent for 22 days, but not for 42. In dull (diffuse) 

 light, virulence lasted 15 days, in bright sunlight, less than 40 

 hours. It is destroyed in half an hour at 158° F., in 4 per cent, 

 carbolic acid in 15 minutes, in mercuric chloride (1:1000) in 10 

 minutes, and even in concentrated milk of lime. 



Pathogenesis. The virus is deadly to chickens and turkeys, 

 while ducks, geese, swans, pigeons, mice, Guineapigs, and rab- 

 bits are immune. 



Symptoms. The affected chicken becomes listless, with ruffled 



feathers, blood-red or dark leaden comb, drowsiness, coma and 



atony. The first day the affected hen leaves the flock and is 



found apart, dull and apathetic, with slightly elevated tempera- 



199 



