112 



POULTRY DISEASES 



liver cells as they are first affected (cloudy swelling); B, the cells 

 farther along in the disease process, in which it may be noted that 

 the nucleus has disappeared and the cell is disintegrating (necro- 

 sis) ; C, the congested vessels (passive congestion); D, white blood 



'cells (eosinophiles) referred 



may also be 

 areas giant 



to above. There 

 noted in these 

 cells. 



Fig. 47, b, illustrates a giant 

 cell; a, protozoa causing the 

 disease. A like microscopic 

 examination of sections from 

 the kidneys indicates that 

 poisonous products have been 

 taken up by the blood, for in 

 these sections we find degen- 

 erative changes (congestion, 

 cloudy swelling and focal ne- 

 crosis). 



Fig. 48 shows a microscopic 

 field from a blood smear from 

 a turkey affected by entero- 

 hepatitis. It will be noted 

 that there is an intense eosino- 

 philia. Fig. 49 shows a field 

 from a portion of the kidney, 

 in a state of cloudy swelling 

 and focal necrosis — evidence 

 of absorbed poisonous sub- 

 stance. Fig. 50 shows one of 

 the ceca with a small ulcer- 

 ation caused by the protozoa. 



Symptoms. — Enterohepa- 

 titis is common in turkeys 

 between the ages of one month and one year, although I have 

 seen the disease in birds that were much ohier. Several out- 

 breaks have been studied in this laboratory. Only one ease 

 was found in the hen. It has been reported in the peacock. 



The symptoms are not manifest till the disease has pro- 

 gressed to a considerable extent. The bird is first noticed to 

 be dull, later the wings and tail may droop; the feathers 

 become ruffled and the bird sits around much of the time; 

 diarrhea sui)ervenes, the discharge being of a greenish-yellow 

 color; there is a loss of appetite; the bird grows gradually 

 weaker, showing muscular weakness, droopy wings, and usu- 

 ally dies in from three to ten days after the first symptoms 

 of the disease become noticea])le. In the cases that run hmger 

 the l)ird liecomes emaciated. The head nuiy or may not \\irn 

 purple. Prom the cases in which the head turns purple the 

 disea.se gets its name — blackhead. 



Although turkeys of all ages are susceptible to blackhead, 

 youth suffers most. Cases seldom appear before the thir- 



Fig. 45. Enterohepatitis Ix a Turkey. 

 A, yellowish-white necrotic areas. This 

 liver weighed 452 grams, nearly one pound. 



