DIVISION OF POULTRY 683 



SESSIONAL PAPER No. 16 



BLACK-HEAD IN TURKEYS. 



(Entero-IIepatitis.) , 



BY 



C. H. Higgins, B.S., D.V.S., Chief Pathologist, Health of Animals Branch — 



Department of Agriculture. 



Entero-nepatitis, or black-head, in turkeys is a disease of fowl, infectious in its 

 nature, usually seen in its most aggravated and fatal form among turkeys. Other 

 fowl may be subject to the disease, but losses among them are small compared with 

 the loss among turkeys. The first investigations as to the nature and cause of the 

 malady were made by Dr. Theobald Smith, in Rhode Island, under the joint auspices 

 of the United States Department of Agriculture and the Rhode Island Agricultural 

 Experiment Station, during 1894 and 1895. Various investigators have since taken 

 up the study of the disease as it has become more widely distributed and a distinct 

 menace to the turkey-raising industry. Detailed information relative to the manner 

 in which the disease is transmitted from an affected to a healthy bird is lacking. It 

 is believed that this infection is direct from the droppings or from the ground on 

 which they have been deposited. There is still some difference of opinion as to the 

 exact organism responsible for the lesions produced, but it is generally conceded to 

 be a minute protozoan parasite. We anticipate conducting experiments and hope to 

 be able to arrive at some definite conclusions regarding these and other unsettled 

 points. 



LOSSES. 



The losses from this disease have been enormous, and I believe that it is a factor 

 lesponsible for the high price of turkeys. The extent of these losses is well indicated 

 from the fact that two decades ago a single small island (Block island) off the Rhode 

 island coast provided two tons of marketable birds each year, while 

 to-day but five hundred pounds are available from the same locality. State- 

 ments are also current that in localities in Ontario where ten carloads of birds were 

 available eight years ago it is now difficult to secure two carloads. The reason to be 

 ascribed for this falling off in production is the difficulty of rearing stock that can 

 withstand this affection. 



In Canada the disease was first mentioned by Gilbert in the Experimental 

 Farms Report for 1900. It has since been repeatedly reported upon evidence obtained 

 at this laboratory and at the Bacteriological Laboratory of the Guelph Agricultural 

 College. From the information which we have obtained through communications 

 received at this laboratory, it is evident that there is not a province in Canada where 

 entero-hepatitis does not make its presence felt with more or less severity each 

 season. In some portions of the country the disease has made such inroads on the 

 turkey industry as to almost prohibit the raising of this class of fowl. 



The usual history concerning losses is that an individual having a few fowl 

 desires to supplement his poultry operations by raising a few turkeys. He is an 

 unsuspecting buyer of parent stock or sittings of eggs until experience has made him 

 painfully aware of the fact that he has bought with the birds or eggs the infective 

 agent of this disease which later separates him from his original investment and the 



