ASPERGILLOSIS

A disease that exists more commonly than is usually suspected, and is the cause of the death of large numbers of young chickens

Symptoms. Fowls gradually lose weight, mope, and die without any pronounced ailment except difficulty in breathing. In adults the disease may be mistaken for tuberculosis and in chickens for white diarrhea. Aspergillosis of chickens is dealt with under brooder pneumonia. tem symptoms are whitish or yellowish growths on the windpipe, that can only be definitely diagnosed under the microscope.

Cause. A fungoid growth in the windpipe and bronchial tubes, sometimes extending to the lungs and liver. Fig. 8 shows the spores and filaments of the species of aspergillosis most commonly responsible

Post-mor

FIG. 8.-ASPERGILLOSIS

On left-Windpipe cut open. On right-A fungus that causes aspergillosis

for this disease. Infection may be due to musty grain or dirty straw.

Treatment. No medicines are of any avail. Protection lies in not using musty grain or moldy litter. Burn dead birds.

BLACKHEAD OF TURKEYS

A very serious disease, making the successful rearing of turkeys difficult and in some cases impossible.

Symptoms. Young turkeys, or poults, are most commonly attacked; there is loss of weight and loss of appetite; the bird appears listless and stands by itself with

drooping wings and tail. Diarrhea is generally one of the symptoms. The comb often turns a dark purple-a symptom that has given rise to the name blackhead. Death generally follows an attack fairly rapidly, but in some cases the disease may take a chronic form, while it is believed that recovery is occasionally effected.

Post-mortem symptoms. The cæca (see Fig. 32) are enlarged, are diseased in parts, and are more or less plugged with cheesy matter and pus. The liver is diseased, being sometimes very much enlarged and covered with yellowish necrotic areas, generally depressed in the centre (see Fig. 24d). In cases of an acute attack, especially in young birds, one of the cæca only may be affected and the liver may not be invaded. The extent of the necrotic areas and the degree of the enlargement of the infected organs may vary greatly in different cases.

Cause. The cause of blackhead has been shown by Drs. Cole and Hadley to be a coccidium. A full account of their work is published in Bulletin 141 of the Rhode

Island Experiment Station. Coccidia enter the digestive tract of the healthy turkey by means of food or water infected by the excrement of a sick bird. The organisms. pass along the alimentary canal until they reach the cæca, the lining of which they attack, giving rise to the conditions mentioned under post-mortem symptoms. How the infection spreads from the cæca to the liver is not clear.

It has been conclusively proved that fowls, as well as pigeons, sparrows, etc., act as hosts for these parasites. Although adult fowls have a great degree of resistance themselves, they are a means of carrying infection to turkeys.

Eggs may be one of the means of spreading the disease, as they may become contaminated in the oviduct or the cloaca of birds affected with blackhead.

Treatment. No remedy or satisfactory method of prevention has been discovered. The difficulty of effecting a cure is obvious when the nature of the disease is con

sidered. Drs. Cole and Hadley summarize measures of prevention as follows:

1. Protect the yards and flocks which may have the good fortune to be uninfected with the blackhead organism by a thorough examination of all new stock, whether turkeys, fowls, geese or other domestic birds.

2. Keep the turkeys on grounds which are as fresh as can be obtained, and above all, keep them isolated from fowls and other domestic birds.

3. Keep every turkey in the flock under close observation in order to separate and at once isolate any bird which gives evidence of the disease. To facilitate such observations it is helpful to leg-band each individual, and to record its weight from time to time. Such a course makes it possible to learn whether any birds are losing weight, and if this is the case, these birds must be regarded with suspicion, and separated from the rest of the flock.

4. If it is known that blackhead is present in any of the poultry, the yard should be kept free from English sparrows, and the poultry houses and grain boxes from rats and mice, which have been shown to carry the causative organism.

5. When it is desired to fatten birds for the market, begin to increase the rations gradually. Never attempt to fatten birds which, in successive weighings, show a loss of weight. Overfeeding does not cause blackhead, but frequently causes the sudden death of birds in which blackhead is present.

6. When birds have died of blackhead, their bodies should be promptly burned or buried in order to prevent the dissemination of the coccidia, either through the ravages of rats or skunks, or consequent to the natural processes of decay.

BREAKDOWN

Not often seen in the poultry yard

Symptoms. The abdomen becomes en