Vaccine Development Against Pasteurella Haemolytica Infections in Sheep

Donachie, W.

doi:10.1007/978-1-4899-0978-7_3

Cited by 10 publications

(8 citation statements)

References 34 publications

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“…Although resistance to A2 disease correlates with antibody titers, the capsular polysaccharide associated with A2 specificity is less immunogenic than capsular antigens associated with other serotypes (Adlam, 1989). Protective immunity to an A2 strain was enhanced in domestic sheep by inclusion of iron regulated proteins (IRP) produced by organisms when grown in vivo (Donachie, 1995). Bacteria in the environment besides P. haemolytica A2 strains stimulate production of cross-reacting antibodies (Adlam, 1989) and may have been responsible for a portion of the antibodies detected against A2 cells in sera of bighorn and domestic sheep in our study.…”

Section: Discussionmentioning

confidence: 67%

“…Jones et al (1989) determined that disease resistance in domestic sheep correlated with serum antibody titers and that sheep could be passively immunized by intravenous or intraperitoneal infusion of sera from sheep convalescent from experimentally induced pasteurellosis or immunization. Antibodies against antigenic components have been found to confer protection against disease associated with heterologous Pasteurella strains as well as the homologous vaccine strains (Donachie, 1995). Mosier et al (1989) found that vaccination of calves with A1 P. haemolytica resulted in production of antibodies against numerous antigens; however, only a portion of the antibodies were found to be associated with disease resistance.…”

Section: Discussionmentioning

confidence: 99%

“…within hours of birth (Al-Sultan and Aitken, 1985). Although lambs at 4 and 8 wk of age did not have evidence of antibody production against these organisms nor components of a Pasteurella vaccine, older conventionally reared domestic sheep develop antibodies, believed to be in response to colonization, and associated resistance to naturally occurring and experimental induced disease (Gilmour and Donachie, 1995). Antibodies present in sera of sheep in our study prior to vaccination and those in NV groups appear to have resulted, at least in part, due to response to stimulation by organisms which colonized their mucous membranes.…”

Section: Discussionmentioning

confidence: 99%

“…Biotype T organisms commonly colonize the mucosa of the upper respiratory tract and tonsils of bighorn and domestic sheep. Antibodies detected in the sera of conventionally reared domestic sheep has been attributed to antigenic stimulation from these organisms (Donachie, 1995).…”

Section: Discussionmentioning

confidence: 99%

“…Leukotoxin neutralizing antibodies resulting from vaccination of bighorns #6 and #9 did not remain elevated in these animals longer than 16 wk PV as it did in bighorns which had experienced pneumonic pasteurellosis or in domestic sheep without a history of disease. Neutralizing antibody titers have also been found to correlate with disease resistance (Gentry et al, 1985, Donachie, 1995. Incorporation of IRP's and leukotoxoid in vaccines may provide a means of stimulating immunity to disease associated with a broad spectrum of biotype A serotypes.…”

Section: Discussionmentioning

confidence: 99%

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Immunologic Responses of Domestic and Bighorn Sheep to a Multivalent Pasteurella Haemolytica Vaccine

Ward

Hunter

Rudolph

et al. 1999

Journal of Wildlife Diseases

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The efficacy of a Pasteurella haemolytica vaccine (serotypes A1, A2, and T10) to induce humoral antibodies and alter colonization of the upper respiratory tract by related P. haemolytica spp. strains was evaluated in 10 bighorn (Ovis canadensis canadensis) and 10 domestic (Ovis aries) sheep. Sheep of each species were divided into five pairs based on age and history of respiratory disease. One sheep in each pair was vaccinated twice 2 wk apart with 2 ml of vaccine (VAC group) and the remaining animals (NV group) were injected with 2 ml of sterile saline. Mild, transient lameness was the only observed adverse effect. Blood sera from the sheep were tested for agglutinating antibodies against whole cells of A1, A2, and T10 and for leukotoxin neutralizing antibodies. Antibody titers were expressed as the reciprocal log 2 of the highest reactive dilutions. Domestic sheep Ͼ1-yr-old and two bighorn sheep with a history of A1 infection had higher titers throughout the study against A1 cells than domestic sheep Ͻ1-yr-old and bighorns without a history of A1 infection. Both domestic and bighorn sheep had log 2 titers of 8 to 12 against A2 cells and 6 to 12 against T10 cells during this time. Bighorn sheep in the VAC group had 2 to 32 fold titer increases for A1 cells by 2 wk post-vaccination (PV) compared to 0 to 2 fold increases in VAC domestic sheep. Two to 16 and 0 to 8 fold increases in antibodies titers to A2 and T10 cells, respectively, were detected in sera of both VAC groups. Sera of bighorn sheep with a history of respiratory disease and all domestic sheep had log 2 leukotoxin neutralizing antibody titers of 4 to 14 in contrast to Յ2 in sera of bighorn sheep without a history of respiratory disease. Neutralizing antibody titers of two bighorns without a history of respiratory disease in the VAC group increased from log 2 0 to 5 in one and from 0 to 9 in the other 2 wk PV. Antibody increases in these animals were no longer evident at 16 wk PV while titers of animals with histories of disease remained relatively stable. The types and numbers of Pasteurella spp. isolated from nasal and pharyngeal swabs varied throughout the study without conclusive evidence of suppression of colonization. Although the animals were not experimentally challenged to determine the efficacy of the vaccine, one VAC and one NV bighorn sheep died following introduction of an A2 P. haemolytica strain when leukotoxin neutralizing antibodies had returned to pre-vaccination levels. This vaccine appeared to be safe for use in bighorn sheep and stimulated moderate but transient increases in antibody levels which should provide some protection against naturally occurring disease. A vaccine which would induce production of high and maintained antibodies against multiple strains of P. haemolytica would be valuable for use in bighorn sheep maintained in captivity or when captured for relocation.

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Section: Discussionmentioning

confidence: 67%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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