EXPERIMENTAL REPRODUCTION OF PSEUDOTUBERCULOSIS IN ANIMALS 111 



Intraperitoneal injection is fatal in 24 to 36 hours. Post mortem, there is a rich fibrinous 

 exudate, containing enormous quantities of plague bacilli. Infection by the mouth, nasal 

 mucosa, and vaginal mucosa is not constant. 



The animals are very sensitive to conjunctival infection. By inhalation or intratracheal 

 inoculation it is possible to set up an acute primary pneumonia. Symptoms appear in 

 48 hours, and death occurs in about 72 hours. At necropsy there is a confluent broncho- 

 pneumonia with oedema or commencing necrosis of the lung tissue (Bessonowa, Kotelnikow, 

 and Semikoz 1927, Bablet and Girard 1933). However infection occurs, the organisms 

 sooner or later gain access to the blood stream. At post mortem they can be isolated 

 from the blood, spleen, liver, lung, and bone marrow. After bacteraemia has developed, 

 the organisms may often be found in the bile, urine, and less frequently in other excretions 

 (Semikoz, Bessonowa, and Kotelnikow 1927). 



Rabbits are less susceptible to plague than rats and guinea-pigs, but they can generally 

 be infected by subcutaneous inoculation (Dieudonne and Otto 1912). 



Monkeys vary in susceptibility. The German Commission (Report 1899) infected 

 Macacus radiatus by subcutaneous and intraperitoneal inoculation, and by feeding. This 

 species was not nearly so susceptible, however, as Preshytes entellits {Semnopithecus entellus) 

 which succumbed after minute quantities of plague culture subcutaneously. 



Experimental Reproduction of Pasteurellosis in Aninia,ls. 



Most animals are susceptible to experimental infection with Pasteurella. On 

 primary isolation, a strain from one species of animal may prove of low infec- 

 tivity for other species (Karlinski 1890), but this is by no means always true. 

 Magnusson, for example, found that his reindeer organism was pathogenic to 

 mice, guinea-pigs, rabbits, sheep, dogs, and pigeons. The most suitable animals 

 for inoculation are the mouse, rabbit and pigeon. 



Mice. — Subcutaneous inoculation of a small quantity of a 24-hour8' broth culture 

 proves fatal in 24 to 48 hours. Post mortem, there may be local oedema and congestion, 

 with practically no other signs. Mcroscopically the bacilli are found in large numbers 

 in the blood and viscera. If very few organisms are injected, or a culture of relatively 

 low virulence is used, the mouse does not die for 2 to 8 days, or even longer ; at necropsy 

 there is a fibrino-purulent pericarditis, a layer of fibrin over the pleura, partial consolidation 

 of the lungs, and not infrequently a purulent exudate in the peritoneum. Bacilli are 

 plentiful in the blood and organs. Intraperitoneal inoculation is more rapidly fatal. 



Rabbits can be infected by subcutaneous, intraperitoneal, intravenous, intratracheal, 

 or intranasal inoculation. Death occurs in 2 to 5 days as a rule after intraperitoneal 

 injection, with lesions similar to those in mice. In addition there may be a hsemorrhagic 

 tracheitis (Magnusson 1914), and hypersemia of the kidneys and intestine (Poels 1886). 

 Intranasal insulflation of the bacilli is often followed by snuffles or pleuro-pneumonia 

 (Beck 1893, Webster 19246, 1926), and sometimes by purulent otitis media (Smith and 

 Webster 1925). 



Pigeons are very susceptible to intravenous or intraperitoneal, less so to intramuscular, 

 injection. Death occurs in 24 to 48 hours. Bacilli are abundant in the blood. 



Experimental Reproduction of Pseudotuberculosis in Animals. 



The term pseudotuberculosis is used to refer to a number of diseases that are 

 caused by different organisms (see Chapter 73). We shall restrict ourselves here 

 to the lesions due to Past, pseudotuberculosis. The experimental disease can be 

 produced in guinea-pigs, rabbits, rats, mice, and according to Pallaske (1933), to 

 whom reference should be made for a detailed account of the lesions produced, in 

 cats, pigeons, canaries, and turkeys. For laboratory purposes the guinea-pig is the 

 most suitable animal to study. 



