ANNUAL REPORT, 1947-48 73 



and Variant forms and apparently were in active form variation at the time of 

 isolation. This was supported by the fact that after several transfers on arti- 

 ficial media their antigenic form tended to become Standard. It is ol interest 

 to note that to date all infected flocks (including Standard, Intermediate, and 

 Variant forms of infection) were originally identified by the Standard form anti- 

 gen. Variant form infection has not been a problem in the establishment and 

 maintenance of pullorum-free flocks in Massachusetts thus far. 



Previous to March 31, 1948, twenty-seven 5. pulloriiin cultures, isolated from 

 specimens representing acute infections in nine flocks, were typed for antigenic 

 characteristics. One culture was Variant in form. Cultures from eleven birds 

 from two chick flocks, both of which were hatched from eggs laid by a flock in- 

 fected with an Intermediate form organism, showed mixed culture forms. Stan- 

 dard, Intermediate, and Variant forms being found in individuals. The remain- 

 ing fifteen cultures from six flocks were of Standard form. 



Additional work is being done to determine the practical significance of form 

 variation in S. pullorum as it aff'ects antigenic response and agglutination reac- 

 tions. 



3. Diagnostic Service. During the calendar year of 1947, 4,627 specimens 

 were received in 1,010 consignments, of which 660 were delivered in person. 

 This represents a considerable increase in the number of consignments, 146 of 

 which were for immunity tests in order that the flocks might be included in the 

 infectious bronchitis and Newcastle disease programs. The specimens were 

 classified as follows:- 4,116 chickens; 393 turkeys; 30 canaries; 12 canine feces; 

 11 each of mink, and rabbits; 10 pheasants; 6 each of fish and pigeon; 4 rats; 

 3 each of bovine semen, ducks, and ruffed grouse; 2 each of bovine feces, equine 

 semen, grosbeaks, guinea pigs, and swine; and one each of bovine, bovine fetus, 

 bovine organs, bovine pus, goat feces, meat, ovine organs, rabbit liver, and swan. 



Tumors (110), coccidiosis (82), and fowl paralysis (57), which in past years 

 have been consistently among the most common diagnoses, were displaced by 

 infectious bronchitis (150) and Newcastle disease (115). In 113 cases of respira- 

 tory infection a definite diagnosis was not made. Avian tuberculosis was identi- 

 fied on two premises. Fowl cholera was diagnosed on 18 premises. Eleven of 

 these represent new known foci of infection, and on two others there had been 

 no evidence of infection for four and seven years, respectively. Fowl typhoid 

 was identified in 24 outbreaks on 20 premises, 15 of which represent new known 

 foci of infection. 



The number of outbreaks of fowl typhoid during the past four years suggests 

 that this disease, if not checked, may become a serious problem to the industry. 

 During the past two years, each flock was visited or the owner was otherwise 

 contacted to assist in formulating an eradication program. Agglutination tests 

 are conducted in flocks which are not depopulated and where testing seems indi- 

 cated. The flock owners are contracted during the year following the outbreak to 

 obtain information on the success of the eradication program. Attempts are 

 being made to inform those engaged in the poultry industry concerning the prev- 

 alence and potential dangers of the disease. Infection reappeared in 1947 on 

 four of the 19 premises which were known to have been infected in 1946. The 

 effort to eradicate infection on two of these premises was believed to have been 

 insufficient. Infection on the third was believed to have been carried over in 

 an uncleaned pig pen adjacent to the range. An explanation was not found for 

 the reappearance of infection on the fourth premise. 



A severe conjunctivitis and keratitis in young chickens was present in five 

 consignments. This apparently is a relatively new condition as only five cases 



