88 Fowl Cholera, 



(1879) and later Pasteur (1880) coiiliniuHl their findings and succeeded 

 in growing the bacteria in artificial ])ouillon, thus enabling them to 

 study their pathogenic characteristics. Pasteur carried out his first 

 fundamental experiments on the attenuation of bacterial cultures and 

 on immunization with such attenuated cultures with the bacilli of fowl 

 cholera. Valuable contributions regarding the etiology of the disease 

 were also furnished by Kitt and Lignieres. 



Occurrence. Fowl cholera occurs extensively in Europe 

 (with the exception of Great Britain), in North America and 

 in South Africa, and causes very heavy losses, especially among 

 the liner breeds. The extent and value of the losses cannot 

 be accurately estimated; as a matter of fact, in some of the 

 localities, occasionally half or even a larger proportion of the 

 flocks are annihilated. Aside from the money value of the 

 dead and slaughtered fow^ls, the total loss is considerably in- 

 creased by the temporary retrogression of fowl breeding in 

 the affected localities as well as by the reduction of the egg 

 production. 



In the year of 1908, 14,397 chickens, 13,877 geese, 4,795 ducks, 272 pigeons and 

 256 other fowls died or were slaughtered in 776 townships in Germany on account 

 of cholera. The greatest number of losses occurred in the government districts, 

 Potsdam, Bromberg, Oppeln, Allenstein, andPosen (in the last 3 years the number of 

 cases was reduced from 74,329 to 33,597). The looses of the other countries are 

 not known, but the disease exists at the present time to a great extent in "Russia, 

 Italy, Austria, Hungary, France, Bulgaria, California, etc. 



Etiology. The bacillus (bipolaris) avisepticus (bacillus 

 eholerae gallinarium s. avicida, pasteurella avium) belongs to 

 the smallest of the bipolar bacilli w^ith wdiich it, however, cor- 

 responds in the morphological and cultural characteristics (see 

 page 79). In fowd blood the bipolar staining is particularly 

 well marker! (see fig. 24 on page 79) ; peptone bouillon is made 

 uniformly cloudy with or without the formation of a slimy sedi- 

 ment (according to Hertel the bacilli sometimes pass through 

 a porous Berkefeld filter). 



Tenacity. The bacteria of fowl cholera remain alive in manure for at least 

 3 months (Gaertner), in putrefactive carcasses and in garden soil for 3 months 

 (Kitt), in water with the exclusion of air and at a temperature of 5 to 6 de- 

 grees for 18 days (Hertel). They also show a considerable resistance to cold 

 (according to Kitt they resist freezing for 14 days, and according to Hertel their 

 virulence is gradually reduced at minus 13 degrees), but they are less resistant 

 towards other harmful influences. Thus, when dried in exudate in the air, and 

 under the influence of sunlight they lose their virulence in 48 hours, if the light is 

 excluded in 72 hours (Heifer), whereas organs of carcasses are sterilised by a 

 temperature of 45 to 50° C. in % hour, and in 10 minutes at a temperature of 

 80-85°C. (Kitt). The following disinfectants have a destructive action on the organ- 

 isms: 1% carbolic acid, %% sulphuric acid (Salmon), 17o chlorate of lime, and 5% 

 milk of lime (Jiiger). The blood and loose excrements are positively disinfected 

 by thoroughly mixing them with a 5% copper sul])hate solution (Colin). Turf 

 dust has also a disinfecting action (Ulmic acid), for when bloody intestinal con- 

 tents are mixed with it the infectiveness of the bacilli is destroved in 48 hours 

 (Hertel). 



Pathogenicity. The blood of chickens affected with cholera 

 as well as fresh pure cultures produce the disease in fowls after 



