Schantyr, ignoring the cocci, describes three bacilli which cause three different diseases (distemper, abdominal typhus, and typhoid), but the distinctions are not clear nor generally accepted.
Lignieres and Even, in Argentina, and dealing with the more susceptible high bred dogs (fox terriers, great Danes and carlins), found constantly in the blood of the dog, in the early stages of the disease, a long, delicate bacillus, nonmotile and easily stained in aniline, but not by Gram’s method. Inoculated on the Guinea pig it shortens, approximating rapidly in successive passages to a cocco-bacillus, and assumes the general characters of Lignieres’s pasteurella. Different bacteria may be found in the lungs, bronchial and nasal mucus, tears and vesicles.
Lignieres’s pasteurella is inoculable on the Guinea pig, mouse, rabbit, and dog, producing the symptoms of local or general infection. Two centigrammes, subcutem, in the Guinea pig, produced a local œdema, disappearing in four or five days and securing immunity. Five cc. subcutem proved fatal in 48 hours; intraperitoneal in 24 hours. In the rabbit 1cc., subcutem, caused local œdema for 2 days and hyperthermia (104°) for 3 days; 1cc. intravenously, caused fever for 3 weeks, diffluent blood and hæmorrhagic lesions in lungs, liver, kidneys, bowels, spleen, and serosæ. In the mouse, 4 to 8 drops, subcutem, caused œdema, and recovery or death in 2 to 4 days. In such cases the microbe was found in pure cultures in the blood or inoculated tissues.
Inoculations of the pure cultures on dogs produced in different cases, gastro-enteritis, pneumonia, pleuro-pericarditis, and arthritis, in various combinations. If the animal survives it is immune.
Grown on peptonized bouillon, neutral or slightly alkaline, the bacillus forms, in 24 hours, small granular colonies which fall to the bottom, leaving the liquid clear. The addition of serum renders this more abundant without causing opacity.
On pancreatic bouillon the growth is very free without indol.
On gelatine plates there are fine punctiform colonies, transparent, but becoming white and opaque in 8 or 10 days. Similar colonies form in stab and streak cultures. The gelatine is not liquefied. Cultures in milk cause neither coagulation nor acidity. There is little or no growth in hay tea, on potato, nor in vacuum. The cultures have the peculiar odor of the pasteurella.
Virulent Products. Infection is present sooner or later in all the morbid animal products. The nasal mucus, bronchial exudate, saliva, tears, contents of the cutaneous vesicle, milk, contents of the bowels, and the blood have been successfully inoculated on susceptible subjects. Inoculations with blood failed with Bryce, but proved successful with Konnhauser, Krajewski, Even, Lignieres and Physalix, so that the first named cases may be explained by a prior immunity, or by a too advanced stage of the case which furnished the matter. The virulence is not lost nor even diminished by drying at ordinary temperatures, freezing (10° F.), nor by moderate dilution in water. Prolonged exposure at ordinary temperature, however, reduces the virulence, which is greatly impaired in 15 to 25 days (Laosson), or, if dried, in three months and upward (Krajewski). Virulence is easily destroyed by disinfectants,—thorough washing (Menard) hypochlorous acid (Trasbot), chloride of lime, mercuric chloride, etc.
Forms of Distemper. This disease is extremely protean in its manifestations. Many cases, in country districts especially, are manifested by a slight fever, with a catarrhal condition of the mucosæ of the nose, eyes, and throat. In other cases there may be simply a slight conjunctivitis or keratitis, and in still others a cutaneous eruption, papular, vesicular or pastular. In some instances there is slight gastric or hepatic disorder with inappetence nausea, and vomiting or some irregularity of the bowels. In such cases recovery may take place in eight or ten days.
In the more severe forms, especially seen in house and city dogs, and in high bred and confined dogs generally, the fever is high and persistent and the disorders often predominate in particular organs, hence we see a catarrhal form, a conjunctival, a bronchitic, a pulmonary, a gastro-intestinal and hepatic, a cutaneous and a nervous. The severe cases may last for twenty or thirty days or even in their sequelæ for several months. Exposure to cold contributes greatly to a pulmonary attack even in inoculated cases (Lignieres).