DEPARTMENT OF VETERINARY SCIENCE AND ANIMAL PATHOLOGY 



CONTROL OF BACILLARY WHITE DIARRHOEA 



1924-1925 



By p. E. Bransfield 



During the present season the Massachusetts Agricultural Experiment Sta- 

 tion, through its Department of Veterinary Science and Animal Pathology, has 

 continued its activities to control bacillary white diarrhoea of poultry in the 

 State and to eradicate it as far as possible. The attempt this year has been 

 in particular to establish disease-free flocks, from which day-old chicks and 

 hatching eggs may be obtained. The men whose flocks were last year free from 

 disease, or in whose flocks there was only a small percentage of infection, have 

 been given the preference, in so far as was possible, in the order of testing. 

 The establishment of the Massachusetts Association of Certified Poultry 

 Breeders has helped considerably to improve the poultry industry in Massachu- 

 setts, and this department has cooperated with this association to the fullest 

 possible extent. 



Nature of the Infection. 



Bacillarj' white diarrhoea is an infectious disease and chicks which survive 

 its onslaught may become chronic carriers, the seat of infection being the ovaries. 

 The causative agent of bacillary white diarrhoea is the oi'ganism known as 

 Salmonella pullora. The primary source of infection is the hen carrier, which 

 transmits the disease to the eggs and thence to the chicks. Other chicks not 

 originally infected may become so through infected droppings from chicks 

 hatched from infected eggs. Chicks which survive the infection may in their 

 turn become carriers of the disease, thus completing the vicious cycle of trans- 

 mission of the disease. 



The problem of bacillary white diarrhoea control is to locate these carriers 

 and to eliminate them from the breeding flock. The method used is the macro- 

 scopic agglutination test, as described in Control Bulletin No. 27, reporting the 

 work for 1923-1924. 



Service Rendered under the Poultry Disease Elimination Law for the Season 



Ending July 31, 1925. 



During the season just past 66,503 fowls, 3,076 of which were male birds, 

 have been examined for bacillary w^hite diarrhoea by the macroscopic aggluti- 

 nation test. The following tables show the geographical distribution according 

 to breeds, the location of the reactors, the amount of infection among various 

 breeds, and the niunber of flocks having certain limits of infection. 



