734 IOWA DEPARTMENT OP AGRICULTURE 



There is some difference of opinion as to whether the ameba is ever 

 present within the egg of diseased turkeys, but the indications are that 

 the infection is not carried in this way. It no doubt often exists on the 

 outside of the shell, from contamination when the egg passes through 

 the cloaca, and for this reason the eggs should be carefully cleaned be- 

 fore they are put under the sitting hen or into an incubator. 



An important recent conclusion is that common fowls harbor this para- 

 site, although they rarely suffer sufficiently from its attacks to show 

 marked symptoms of disease. They scatter the contagion constantly, how- 

 ever, and young turkeys, being more susceptible, contract a fatal form 

 of the disease and are nearly all destroyed by it. For this reason it is 

 very difficult to raise turkeys on or near grounds where there are com- 

 mon fowls. 



Symptovis. — The symptoms of blackhead are most frequently seen in 

 young turkeys, commonly called "poults," which are from 2 weeks to 3 or 4 

 months old. When young poults are infected experimentally by feeding 

 them diseased livers they usually die in about two or three weeks, but 

 when infected naturally they generally take in a smaller quantity of con- 

 tagion and live a longer time. 



The affected birds at first appear less lively than usual, are not so 

 active in searching for food, and when fed show a diminished appe- 

 tite. Diarrhoea is a nearly constant sypmtom, being due to the inflam- 

 mation of the ceca. As the disease progresses there is more dullness and 

 weakness, the wings and tail droop, and there is often the peculiar dis- 

 coloration of the head which led to the disease being called "blackhead." 

 There is increasing prostration and loss of weight; the affected birds, in- 

 stead of following their companions, stand about in a listless manner, 

 indisposed to move and paying little attention to what occurs about them. 



The greater part of the affected poults die within three or four 

 months after hatching; but with some the disease takes a more chronic 

 form and does not cause death for a year or more. Nearly all die 

 sooner or later from the effects of the disease, but in a small proportion 

 of these there is healing and recovery. 



The finding after death, in young turkeys, of the diseased and thick- 

 ened ceca, plugged with cheesy contents, together with the yellowish 

 or yellowish-green spots in the more or less enlarged liver are sufficient 

 indications to warrant a diagnosis of blackhead. 



Treatment. — The treatment of diseased birds has not given satisfac- 

 tory results. The remedies most often used are sulphur 5 grains, sul- 

 phate of iron 1 grain; or benzonaphthol 1 grain, salicylate of bismuth 1 

 grain; or sulphate or iron 1 grain, salicylate of soda 1 grain. These 

 remedies should be preceded and followed by a dose of Epsom salts (10 

 to 35 grains), or of castor oil (i^. to 3 teaspoonfuls). Fifteen grains of 

 catechu to the gallon of drinking water may also have a beneficial effect. 

 It seems clear, however, that it does not pay to doctor the sick poults and 

 that the only hope of success at present is in preventing their infection. 



The measures of prevention which have been suggested are (1) ob- 

 taining eggs from birds believed to be healthy; (2) wiping the eggs 

 with a cloth wet with alcohol (80 to 90 per cent) before they are placed 



