This disease occurs throughout the country wherever poultry is produced and in recent years has become the most hazardous infectious disease of turkeys. Host range is extensive and includes chickens, turkeys, pheasants, pigeons, waterfowl, sparrows and other free-flying birds.
The causative organism of fowl cholera is Pasteurella multocida. The organism can survive at least one month in droppings, three months in decaying carcasses and two to three months in soil. Pasteurella apparently enters tissues of the mouth and upper respiratory tract. The disease is not transmitted through the egg.
Major sources of infection include:
- Body excreta of diseased birds that contaminate soil, water, feed, etc.,
- Carcasses of birds that have died of the disease,
- Contaminated water supplies such as surface tanks, ponds, lakes and streams,
- Mechanical transmission by contaminated shoes or equipment.
Studies indicate that animals other than birds may serve as reservoirs of infection and actively spread the disease. These animals include raccoons, opossums, dogs, cats, pigs, and vermin.
The disease is seldom seen in chickens under four months of age, but is commonly seen in turkeys under this age. In the peracute form, symptoms may be absent; in the acute form some birds may die without showing symptoms, but many others are visibly ill before death. Characteristic symptoms include stupor, loss of appetite, rapid weight loss, lameness resulting from joint infection, swollen wattles, difficult breathing, watery yellowish or green diarrhea and cyanosis or darkening of the head and wattles.
Lesions may be lacking in birds dying during peracute outbreaks. When present, lesions may resemble those associated with any acute septicemic bacterial infection, often those of fowl typhoid. Typical lesions may include pinpoint hemorrhages in the mucous and serous membranes and/or abdominal fat; inflammation of the upper third of the small intestine; light, firm "parboiled" appearance of the liver; enlarged and congested spleen; creamy or solid collection of material in joints; and cheesy material in the internal ear and air spaces of the cranium of birds having twisted necks. Turkeys may have pneumonia with solidification of one or both lungs.
A tentative diagnosis may be made on flock history, symptoms and postmortem lesions. A definite diagnosis depends upon isolation and identification of the organism.
Properly administered bacterins are helpful in preventing fowl cholera, particularly in turkeys. Their use must be combined with a rigid program of sanitation. In general, as it applies to the use of bacterins in turkeys, complete protection is unrealistic. Follow the manufacturer's recommendations for use of the bacterin. Vaccination in conjunction with treatment is not recommended.
Sanitation practices that aid in preventing the disease are:
- Complete depopulation each year with definite breaks between older birds and their replacements,
- Implement a rodent control program,
- Dispose of dead birds properly,
- Provide safe, sanitary water,
- Clean and disinfect all houses and equipment after disposing of flock,
- Keep birds confined to the house and away from wild feral birds and animals,
- Allow contaminated ranges or yards to remain vacant for at least three months.
Although drugs usually alter the course of a fowl cholera outbreak, affected birds remain carriers and the disease has a tendency to recur when treatment is discontinued. This may necessitate prolonged treatment with drugs added to the feed and water. Sulfa drugs and broad spectrum antibiotics (Penicillin) usually control losses.
