instance. Flock 1, the birds wore maintained on two farms sovoral milns apart and a 

 hichly acute form of the disease occurred on one farm. Control measures were 

 inefTective in checkinc the spread of the disease, which prompted the owner to 

 ilispose of the flock. The hirds on the other farm were tested and revealed three 

 reactors. Salmonella pitUortim was isolated from one bird. A retest of the entirr 

 flock on this farm revealed no additional infected birds. 



Flock 2 represented replacements on a farm that had experienced a serious 

 outbreak of pullorum disease among mature layinp birds. These laying birds were 

 sold after several tests and before the replacement stock reached sexual maturity. 

 \o reactors were detected among the replacement stock when tested for the disease. 

 Flock 3 also had birds on two separate farms. On one farm acute pullorum 

 disease appeared in one building which resulted in serious losses. Medication, test- 

 ing, and partial depopulation were resorted to as measures for tlie elimination of 

 the disease from the premises. 



In all three outbreaks the disease was very costly to the flock owner and the 

 laboratory. A total of 27,44.5 samples was tested from the three flocks. 



Flock 4, an egg-laving flock, revealed an acute outbreak of pullorum disease 

 among pullets that had become sexually mature. This outbreak is being controlled 

 bv depopulation of the farm. 



Also, 1,011 chickens were tested at the Boston Poultry Show in Januarv, 10.^9. 

 Among birds exhibited by Massachusetts exhibitors, infection was detected in onlv 

 one entry. This case has been discussed in previous sections. 



No cases of pullorum infection were detected among chicks during the testing 

 year which is most encouraging. 



The five cases of pullorum disease, one among a small breeding flock and four 

 acute outbreaks among laying flocks, reveal that pullorum disease is still present 

 in Massachusetts and mav cause serious losses not only in breeding flocks but also 

 in nonbreeding flocks. The number of pullorum diseased flocks is gradually de- 

 clining, and it is hoped that in the near future no cases will be detected. 



It should be noted that fowl typhoid was not identified in either tested breed- 

 ing flocks or among cases submitted for routine diagnosis during the testing year. 



The cooperation received from the flock owners has been most gratifying in 

 our eff'orts to eliminate the known foci of infection. Also, appreciation should be 

 extended to the County Extension Service and the Massachusetts Department of 

 Agriculture for the valuable assistance given in the eradication of these flock in- 

 fections. Credit should also be given to the diagnostic laboratories at Waltham and 

 Amherst for identifvinsj these outbreaks. 



OTHER SALMONKLLA INFECTIONS 



In September. 19.^8, one breeding flock tested with pullnriun antigen rcn'ealed 

 three doubtful reactors. The agglutination reaction obtained with serum from 

 one of the reactors appeared very suspicious of infection. When this bird was 

 examined at the laboratory. Salmonella enteritidia was recovered. Since so few 

 reactors were detected, it was interpreted that this infection might not be of sig- 

 nificance. However in March, 1959, the breeder-hatcher encountered an acute 

 outbreak of salmonellosis in two chick flocks that proved to be caused by S. enteriddis. 

 The breeder-hatcher was advised to retest that portion of the flock that had earlier 

 revealed S. enteritidis infection. A total of 940 hens was retested and 4.68 percent 

 reactors were detected. Four reactors were submitted to the laboratory and S. 



11 



