An abundant, wholesome, easily digested diet, pure air, a dry stall and protection against cold are essential.
CHICKEN CHOLERA. FOWL CHOLERA. CHICKEN TYPHOID. CHICKEN PASTEURELLOSIS.
Definition. Historic notes. Bacteriology: Bacterium choleræ gallinaceæ, nonmotile, with polar stain, bleached by iodine, non-liquefying, causes septicæmic lesions. Lignieres’ bacillus, culture features non-gasogenic, acidifies dextrose; vitality in disinfectants; survives drying. Accessory causes: new birds in flock, or eggs for hatching, mingling of flocks, manure, watershed, streams, ponds, dust, wild birds, buzzards, rabbits, insects, infected soil. Susceptible animals: hens, doves, peafowl, pheasants, parrots, ducks, small birds, guinea pigs, rabbits, white and gray mice. Effect on sheep, horse, man, cow, frog. Incubation 18 to 48 hours. Symptoms: in fulminant cases rarely seen, in acute, anorexia, depression, debility, apathy, ruffled feathers, sunken head, neck, wings, tail, tremors, nasal and buccal discharge, hyperthermia, sighing, violet comb and wattles, thirst, pultaceous fæces, later glairy, green and fetid. Temperature becomes subnormal, inability to rise, stupor, convulsions, death in 1 to 3 days. Mild cases last 7 days. Cases caused by one microbe have slough only. Lesions: congested, petechiated, hæmorrhagic intestinal mucosa; contents of bowels watery, frothy, bloody; epithelial degeneration and desquamation; abrasions, croupous exudates, enlarged congested lymph glands, fermenting contents of crop. Petechiæ general, spleen and liver swollen, congested, friable; kidneys congested; lungs hyperæmic or blood gorged. Blood diffluent with microbe. Anæmia. Emaciation. Arthritis. Diagnosis: by rapid spread, infection origin, early excessive mortality, hæmorrhagic lesions, microbe in blood and liquid ingesta. Prognosis: Mortality 90 to 95 per cent. at outset. Prevention: Quarantine new birds, inside screens in summer; burn or acidify manure; exclude buzzards, vermin, wild birds, and visitors; separate sick, kill, burn, disinfect; divide infected flock in small lots; prevent wandering in fowls, destroy insects. Phenic acid subcutem. Immunization: inoculate in breast with one microbe (Salmon): or with weakened virus (Pasteur). Limitations. Treatment: gastric and intestinal disinfection—copperas, mineral acids, carbolic or salicylic acids, aromatics, quinine, naphthol, tar, phenic acid subcutem.
Definition. A febrile hemorrhagic septicæmia of chickens and other fowls (pigeons, ducks, geese, parrots, etc.) communicable to certain rodents and other animals, and characterized by a short incubation, rapid progress, great prostration, violent diarrhœa usually greenish, and a high mortality (90 to 95 per cent.).
History, Geographical distribution. It is quoted as prevalent in Lombardy in 1789, in East India in 1817, in France in 1825, and generally in Europe and America in the last half century.
The losses from the ravages of this disease are far greater than the average value of the individual animal would lead one to suppose, but with domestic fowls numbering 300,000,000 and a yearly egg crop bordering on a billion dozens it may well be called enormous.
Bacteriology. Chicken cholera is caused by a very small ovoid bacterium (B. Choleræ gallinaceæ) about 0.3 to 1.8μ long, as found in the blood and tissues of the fowl. It has the general characters of the groups which cause hemorrhagic septicæmia, thus: 1. It fixes, above all at the poles, the ordinary anilin colors; 2. It is decolorized by the methods of Gram and Wiegert (iodine solutions); 3. It grows on gelatine without liquefying it; 4. It produces acute septicemic lesions; 5. It tends to polymorphism when grown under different conditions. In the peritoneum of the guinea pig it forms cocco-bacilli tending in acute and violent cases to diplococci. Fed to rabbits it appears in the fæces as a minute bacillus. Even the mode of staining causes a difference in appearance. Fixed in alcohol-ether, and then stained in Ziehl’s phenated preparation, coloring is polar, and the central area clear. If in place of Ziehl’s fluid, hot fuchsin solution is used warm for ½ a minute, bacillus or cocco-bacillus is shown (Lignieres). It is nonmotile, though some observers have been misled by Brownian movements. There are no flagella. In old bouillon cultures short chain forms are met with. No spores are formed.
From fresh cultures, in flask or in animals, the bacterium grows readily in alkaline culture media. In bouillon a turbidity ensues, and after some days pellicles form on the surface and walls, and the liquid slowly clears. The addition of a little blood serum, sugar or glycerine encreases and hastens the growth, while acid retards or prevents. This is common also to other septicemic germs. In gelatine growth is tardy, but in two or three days there are whitish glistening colonies, becoming opaque later, and appearing granular if slightly magnified. In punctures minute colonies form along the line of culture and one at the surface, at first translucent; later opaque. On agar the colonies grow faster with similar appearance. On gelose at 37° C. the colonies are blueish and iridescent, at first, and later opaque. If the germ has been repeatedly passed through the Guinea pig, they are more translucent. On potato with alkaline surface, there is a delicate grayish yellow growth after 48 hours; if acid, growth ceases. In milk there is no coagulation nor acidification for four weeks; then it becomes slowly clear and opalescent. With sugars it is not gas producing. With dextrose it forms an acid solution; with saccharose or lactose an alkaline one. Cultures in peptone gave a strong indol reaction (V. A. Moore). Lignieres found no indol in cultures in pancreatic bouillon.
The bacterium perishes when heated to 58° C. for fifteen minutes. It dies in carbolic acid solution (1:100) in five minutes; in sulphuric acid solution (0.25:100) in ten minutes; in lime water in ten minutes; and in sulphur fumes in three hours. Easily destroyed by disinfectants, it remains potent for months in flasks or buildings that are not subjected to disinfection. It is not killed by drying (T. Smith and V. A. Moore) nor by zero temperature maintained for seventeen hours.
The cultures, especially those made in agar have a very characteristic odor.