Pasteurella anatipestifer infection in turkeys

In a case of excessive mortality in seven-week-old turkeys, the primary lesion at necropsy was severe fibrinous pericarditis and epicarditis. After 48 hours of incubation at 37 C, Pasteurella anatipestifer was isolated. The infection responded to antibiotic therapy with a combination of neomycin and oxytetracycline in the drinking water. The lesions suggested chlamydial infection, but cultural procedures for chlamydia were negative.     

Pasteurella anatipestifer infection in commercial meat-type turkeys in California

A disease outbreak characterized by respiratory signs, occasional neurologic signs, and increased mortality in commercial meat turkeys from four separate companies in central California was investigated in the late summer and early fall of 1986. The disease syndrome affected turkeys from 6 to 15 weeks of age and caused a severe fibrinous pericarditis, perihepatitis, and airsacculitis. Bacteriologic and serologic examinations as well as virus- and chlamydia-isolation attempts initially failed to implicate an etiologic agent. Eventually culture attempts were made in a 5% CO2 incubator, resulting in isolation of Pasteurella anatipestifer. The disease syndrome was reproduced in young turkeys and broiler chicks inoculated with the organism.     

Genetic variation in resistance of turkeys to experimental challenge with Pasteurella multocida.

Six hundred fifty-five male and female turkeys representing four genetic lines were challenged in 10 experiments over a 3-year period with a field isolate of Pasteurella multocida. Poults were challenged at 45 days of age with 1 ml of an inoculum containing 1.2 x 10(7) bacteria per ml. The lines of turkeys included two randombred control lines (RBC1 and RBC2), a subline (E) of RBC1 selected for increased egg production, and a subline (F) of RBC2 selected for increased 16-week body weight. The number of days from exposure to severe clinical signs or death for Line F (5.8 days) differed significantly from that of Line E (8.2 days), Line RBC1 (8.0 days), and Line RBC2 (8.2 days). There were no significant differences due to sex of poult for number of days from exposure to severe clinical signs or death. Overall mortality observed was 51.2%. Mortality was highest for Line F (72.1%) and differed significantly from that of the other lines. Mortality among male poults did not differ significantly from mortality among female poults.     

Polypeptides associated with Pasteurella multocida infection in rabbits.

Polypeptides from whole cell preparations of Pasteurella multocida serotypes A:12 and A:3 were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to nitrocellulose paper. Antigens were detected by immunoblot analysis, using sera from 3 groups of rabbits. Sera were obtained from rabbits inoculated intranasally with P multocida serotype A:12 or A:3, from rabbits maintained in a rabbitry with enzootic P multocida A:12 infection, and from rabbits maintained in a rabbitry with enzootic P multocida A:3 infection. Immunoblot analyses of pre- and postinoculation sera from experimentally infected rabbits, using serotype A:12 antigen, revealed 3 polypeptides with approximate molecular mass of 28, 30, and 37 kDa that consistently detected antibodies after P multocida-induced infection. Sera from rabbits naturally infected with either serotype, tested against serotype A:12 and A:3 antigens, detected the same polypeptides in both serotypes. Thus, immunologic reactivity to these polypeptides may be useful for serologic detection of P multocida infection.     

Dermal necrosis caused by Pasteurella multocida infection in turkeys

Severe dermal necrosis caused by Pasteurella multocida Serotype 1 was diagnosed in three dressed turkey carcasses and two live turkeys from a commercial flock. The dressed carcasses were among several condemned at a processing plant. The isolate, P. multocida Serotype 1, produced progressive dermal necrosis when experimentally inoculated into injured skin of turkeys. The organism was reisolated from the dermal lesions. The turkey houses were found to be infested by mice; the skin injury and infection with P. multocida probably originated from mouse bites.     

实验性鸭疫里氏杆菌病病理学动态变化

对90只11日龄鸭通过颈部皮下人工接种鸭疫里氏杆菌,分别在感染后12h、24h、36h、48h、60h、72h剖杀,观察其动态病理变化。结果表明,鸭在感染24h后就开始出现浆液纤维素性心包炎、肝周炎、气囊炎,并持续整个病理过程。组织学病变主要为肝脏、心脏、脾脏、气囊等表面增厚,有大量浆液纤维素性渗出物,其中有嗜中性粒细胞和单核细胞浸润;心肌细胞和肾小管上皮细胞颗粒变性,肝细胞脂肪变性和凝固性坏死,脾脏淋巴细胞减少,脑膜水肿充血。证实了鸭疫里氏杆菌主要侵害浆膜和肝脏,引起多发性浆膜炎和肝坏死。     

Laboratory assessment of protection given by experimental Pasteurella anatipestifer vaccine

An experimental, inactivated P. anatipestifer type 'G' vaccine was produced containing 10(9) CFU/0.5 ml and aluminium hydroxide adjuvant (25% final concentration). From comparative pathogenicity studies of field isolates type 'A', 'D' and 'G', the 'G' serotype was selected as being most virulent and suitable for challenge. Vaccination trials, in the laboratory, showed that a single subcutaneous inoculation (0.5 ml) of the above vaccine at 14 days provided the best protection against challenge up to 5 weeks of age. During the course of investigations, maternal antibodies were encountered in ducklings up to the age of 6 days and natural resistance to infection in adults from 5 weeks upwards. Evidence has also been provided of cross antigen-antibody reactions detected in the ELISA, between the 'A', 'D' and 'G' serotypes. A threefold 'protective index' system is described which provides a very sensitive measurement of effective vaccination.     

Molecular epidemiology of Pasteurella multocida in turkeys.

Pasteurella multocida isolated from turkeys during an outbreak of fowl cholera was characterized by serotype and heterogeneity of genes encoding rRNA (ribotype) to investigate the epidemiology of the organism. Isolates were collected between October 1985 and July 1986. The M9 or Clemson University fowl cholera vaccine-like strain was detected in 17% of the flocks with fowl cholera. One particular strain, isolated only from breeder flocks, was recovered from 7 of the 10 breeder flocks examined in this study. Intracompany transmission appeared to be common, implying a failure in biosecurity. Circumstantial evidence indicated that in the field; the incubation period of P multocida in a turkey flock may be between 2 to 7 weeks. Wildlife did not appear to be an important reservoir of P multocida for turkeys during this study period. Ribotyping results tended to discount several of the possible interflock transmissions, as suggested by examination of serotyping results alone; however, serotyping in combination with ribotyping proved helpful in understanding the epidemiology of P multocida in turkeys.     

Acute airsacculitis in turkeys inoculated with Pasteurella multocida

Thirty female turkeys, inoculated into the caudal thoracic air sacs with Pasteurella multocida were examined from 0 to 6 hours post-inoculation (PI). The air sac reacted rapidly and intensely with exudation of heterophils. Circulating leukocyte and thrombocyte numbers remained normal except for an absolute lymphopenia by 6 hours PI. P. multocida was initially isolated from blood at 3 hours PI. Total cell counts increased markedly in air sac lavage fluids by 1.5 hours PI and continued to increase until 6 hours PI. Heterophils predominated in lavage fluids (greater than 94%), with macrophages comprising the remaining cells. Microscopically occasional heterophils were present within air sac blood vessels and perivascularly by 0.5 hour PI. They became more numerous by 1.5 and 3 hours PI when transepithelial migration into the air sac lumen was seen. By 6 hours PI, there was diffuse, severe swelling of air sac epithelium and mesothelium, and bacteria were located in air sac interstitium. Ultrastructurally, endothelial and air sac epithelial cells were swollen and vacuolated Interdigitating processes of air sac epithelial cells were separated. These results indicate that air sacs can be the portal of entry for P. multocida into the systemic circulation, probably via damaged air sac epithelium.     

Genetic variation in resistance of turkeys to experimental infection with Newcastle disease virus.

Seven hundred eighty male and female turkeys representing four genetic lines were challenged in four experiments with the Texas GB strain of Newcastle disease virus (NDV). The lines of turkeys included two randombred control lines (RBC1 and RBC2), a subline (E) of RBC1 selected for increased egg production, and a subline (F) of RBC2 selected for increased 16-week body weight. Mortality in turkeys of subline F (32.5%) was significantly higher than that in turkeys of line RBC2 (15.8%), subline E (17.5%), and line RBC1 (18.4%). At the end of each experiment, surviving birds were tested for antibody to NDV using the enzyme-linked immunosorbent assay (ELISA) and hemagglutination-inhibition (HI) test. Turkeys of subline E and line RBC1 had significantly lower ELISA antibody titers than those of subline F and line RBC2. Subline F had the highest HI antibody titers, followed in decreasing order by lines RBC2 and RBC1 and subline E. No apparent correlation was found between antibody response and mortality after NDV challenge.     

Infection of duck plague carriers with Pasteurella multocida and P. anatipestifer

Mallards (Anas platyrhynchos platyrhynchos) and white pekin ducks (Anas platyrhynchos domesticus) were infected with duck plague virus and challenged with LD20's of Pasteurella multocida and P. anatipestifer. There was no difference between mortality rates of duck plague-infected ducks and controls, suggesting that these organisms do not act synergistically under the conditions of our experiments. There was a difference of about 500-fold between the LD20 of P. multocida for mallards and that for white pekin ducks, indicating that mallards are much more susceptible to avian cholera than white pekin ducks.     

Protection of ducklings with a broth-grown Pasteurella anatipestifer bacterin

Pasteurella anatipestifer (PA) serotypes 1, 2, and 5 grew to high densities in tryptic soy broth and tryptose broth (TB) when the media were continuously shaken or aerated. Growth in 100 ml to 15 liters of TB exceeded an absorbance of 1.0 at a wavelength of 525 nm (about 0.7 for a 1/3 dilution) and contained more than 10(10) colony-forming units per ml. A bacterin was prepared from the three serotypes of PA grown in aerated TB. Two subcutaneous injections of this bacterin protected 70% to 85% of ducklings against experimental challenge with each of the three PA serotypes, which killed 90% to 100% of unimmunized controls. The bacterin could be diluted 1/5 without decreasing protection below 80%. Field studies on Long Island duck farms in 1980 and 1981 demonstrated significant reductions in mortality with the use of the broth-grown PA bacterin.