ERADICATION OF PULLORUM DISEASE 1931-32 49 



with an aqueous suspension of 5. pidloriim found that agglutinins appeared in 

 the blood stream within 3 to 12 days. Hinshaw, Upp, and Moore (46) were able 

 to infect half-day-old chicks by either swabbing or inoculating the organism 

 into the nostrils. Tittsler (89) advanced the hypothesis that pullorum disease 

 may be disseminated by moisture exhaled from an infected lung of a chick and 

 inhaled by a normal chick. Beck and Eber (4) were successful in reproducing 

 the disease in adult hens by subcutaneous inoculation, but not by intravenous 

 or oral administration. Five chicks, two days of age, succumbed to the disease 

 when 2 drops of a suspension of the organism were instilled into the nostrils. 

 Doyle and Matthews (26) reported that exposure of chicks to alfalfa dust con- 

 taining 5. pullorum caused typical pulmonary lesions of pullorum disease. Of 

 the 21 chicks which had been ex-posed to dust containing 5. pullorum, 76 per 

 cent developed typical gross lung lesions of pullorum disease. In the control 

 group, no lesions suggestive of the disease were observed. Gwatkin and Glover 

 (41) isolated 5. pullorum from the nasal passages of two among 61 adult birds 

 examined. 



Edwards and Hull (30) fed 16 pullets and 16 cockerels (9 months old) with a 

 sahne suspension of 5. pullorum having a density equal to 0.25 on the McFarland 

 nephelometer scale. Each pen was given 500 cc. of the suspension. An acute 

 infection was produced. Agglutinins were detected on the first test 7 days after 

 feeding, and on the fourteenth day 16 birds reacted. Seven birds became per- 

 manent reactors and from them S. pullorum was isolated. Miessner (65) reported 

 that Ansorg, Nusshog, and Hof found 5. pullorum in the cloacae of live hens. 

 Weldin and Weaver (97) found that infection may result from the entrance of 

 the organism into the respiratory tract as well as into the alimentary tract, but 

 they believe that the seat of post-hatching infection is more often in the digestive 

 tract than in the respiratory tract. They also reported that chicks inoculated 

 intratracheally revealed no pulmonary lesions, but 2 chicks fed capsules contain- 

 ing the organism showed a pulmonary infection. They stated that "quite evi- 

 dently infection can take place in the chick regardless of portal of entry." 



While it is apparent that S. pullorum may gain entrance into the body through 

 various channels, more information concerning these channels and other possible 

 avenues of infection would contribute to the knowledge on dissemination, control, 

 and eradication of the disease. 



Procedure of the Experiment 



Four different avenues for introducing infective material were selected, 

 namely, instillation into the eye; oral administration; inoculation into the 

 cloaca; and instillation into a skin incision on the plantar surface of the foot. 

 Thirty-five Rhode Island Red birds were divided into three groups and each 

 group was exposed to the infective agent on a different date. Recovered 5. 

 pullorum strains in these experiments were identified by morphological, bio- 

 chemical, tinctorial, and serological characteristics. 



Group I, consisting of 4 pullorum disease-free pullets (approximately 10 

 months of age) was exposed to infection by the ocular route. The birds were 

 placed in individual cages and divided into two lots with 2 birds in each lot. 

 The infective agent was a saline suspension of a 24-hour agar growth adjusted 

 to a turbidity of tube No. 3 of the McFarland nephelometer. One strain of 

 S. pullorum recently isolated from the ovary of a hen was employed. The sus- 

 pension was administered by placing 2 drops (approximately 0.08 cc.) on the 

 conjunctiva of the left eye. Agglutination tests were made at frequent intervals 

 to determine the immunological response to the infection. Dilutions of 1:10 

 and higher were employed to ascertain the titer. Birds in both lots were first 

 exposed to infection on January 26. 



