Vaccination of chickens through the drinking water with a live, Pasteurella multocida, vaccine.

Broiler-type chickens were vaccinated orally at several ages with various dilutions of the Clemson University (CU) strain of Pasteurella multocida vaccine and then challenged orally with virulent strain P-1059 or strain X-73 of P. multocida to determine the degree of protection produced by vaccination. When vaccinated at 8 and 12 weeks of age for 2 consecutive days with a 1:133 dilution of the vaccine and then challenged at 17 and 19 weeks of age with strain X-73 and P-1059 P. multocida, respectively, no significant levels of protection were elicited in the vaccinates. Significant levels of protection were elicited in the vaccinates for 2 consecutive days at 9 weeks and at 13 weeks with 1:133 and 1:50 dilutions of the vaccine respectively, and then challenged at 16 weeks with strain X-73 and at 20 weeks with strain P-1059. Broilers vaccinated at 12 and 16 weeks for 3 consecutive days and then challenged at 20 weeks with strain X-73 showed a highly significant level of protection upon challenge when compared to the controls.

Subcutaneous vaccination of chickens with a live, avirulent Pasteurella multocida, Vaccine.

The immunogenic responses to various routes of vaccination of broiler-type chickens to the Clemson University strain of Pasteurella multocida were evaluated. Broilers were vaccinated at 9 or 10 weeks of age using the oral (drinking water), palatine cleft, ocular, or subcutaneous injection routes. All birds were challenged at 11 or 12 weeks of age with virulent X-73 strain of P. multocida by the palatine cleft method. The degree of efficacy of the various vaccination routes differed among three experiments. Nevertheless, the subcutaneous route produced the greatest degree of protection in all experiments and in two experiments differences were highly significant (P less than .01). Protection levels as high as 95% and 97.5% were attained in broilers vaccinated subcutaneously and no undesirable lesions or cheesy masses formed under the skin in the back of the necks of broilers.

The effect of sulfaquinoxaline feed medication on the immunologic response to a Pasteurella multocida vaccine administered to turkeys via drinking water.

Five groups of turkeys received C.U. strain Pasteurella multocida vaccine in the drinking water for one day. One group received the 0.1% level of sulfaquinoxaline feed medication at the time of vaccination, while 4 other groups received the feed medication 1, 2, 3 and 4 days after vaccination, respectively. Two weeks after vaccination all groups were exposed to a virulent P-1059 strain of P. multocida by the drinking water route. The results suggest that turkeys on the feed medication at the time of vaccination and possibly those receiving the initial fed medication the next day, failed to experience a satisfactory immunologic response. The possible ill effects of the sulfaquinoxaline feed medication on the duration of the immunity was not determined. A schedule and level of feed medication approved by the Food and Drug Administration was used; namely, 2 days on the 0.1% level, 3 days on a normal ration, and then 2 additional days on the 0.05% level of sulfaquinoxaline feed medication.

The ability of blood plasma from drinking water vaccinated turkeys to protect against a lethal challenge of Pasteurella multocida.

Turkeys were vaccinated against fowl cholera with the Clemson University avirulent Pasteurella multocida vaccine strain (C.U. strain), using the drinking water route. Plasma was harvested from these turkeys, which later withstood challenge with a highly virulent P-1059 strain of P. multocida. Baby chicks were injected between the thigh and abdominal cavity with the immune plasma and simultaneously, into the breast muscle, with the same highly virulent strain referred to in the foregoing. The results demonstrated that plasma from turkeys vaccinated by the drinking water route protected baby chicks against intramuscular challenge with a virulent strain of P. multocida and suggest that a favorable systemic immunologic response did occur. This is in contrast to the Minnesota M-2283 strain which, reportedly, produces a localized protection only, when used as a drinking water vaccine.

Immunologic response to turkey poults of various ages to an avirulent Pasteurella multocida vaccine in the drinking water.

Fowl cholera has been reported in turkey poults in South Carolina between 5 and 6 weeks of age. An experiment was conducted to determine the earliest age that poults could be vaccinated with the Clemson University Pasteurella multocida strain (using the drinking water route) that would result in an effective immunity at 5 to 6 weeks of age. In group of vaccinates challenged with a virulent P. multocida (P-1059 strain) at 5 weeks of age, none were infected in groups vaccinated at either 20 days or at 25 days, 1 of 10 vaccinated at 15 days, 3 of 10 vaccinated at 10 days, 6 of 10 vaccinated at 5 days, and 8 of 10 became infected of those vaccinated at 1 day of age. Eight of 10 of each of 2 group of nonvaccinates developed evidence of infection. In groups of vaccinated challenged at 12 weeks of age, 2 of 10 turkeys became infected that had been vaccinated at 25 days of age, 4 of 10 that had been vaccinated at 20 days, 8 of 10 vaccinated at 15 days, 8 of 10 vaccinated at 10 days, 8 of 9 vaccinated at 5 days, and 8 of 9 became infected of those vaccinated at 1 day of age. All 10 of one group of nonvaccinates and all 9 of a second group developed evidence of infection. These results suggest, under the conditions of this experiment, the turkey poults vaccinated at 35 days of age and poults vaccinated at 20 days of age experienced an excellent immunological respone by 5 weeks of age. This response was less evident but, for the most part, still present, at 12 weeks of age.