Western
Meeting of Poultry
Clinicians and Pathologists
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Clinicians and Pathologists
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Pathogenicity Study of an Unidentified Mycoplasma Spp. Imported into Alberta with Eastern Wild Turkeys D. Onderka Provincial Veterinary Laboratory
In late spring of 1992, 98 Eastern wild turkey poults were imported into Central Alberta. They originated from a hatchery in Minnesota, were less than 36 hours old and, therefore accepted by Agriculture Canada under domestic poultry provisions although the import manifest did identify them as wild turkeys. They were raised by a private individual and released in fall in the Olds area to "enhance local wildlife". Presently Alberta has two population of Miriam, wild turkeys, one in the Cyprus Hills and one in the Porcupine Hills. Both are located in Southern Alberta. Release of wildlife is regulated and this particular release of wild turkeys was no approved by Fish and Wildlife. Subsequently, the owner was charged under the wildlife act, convicted and fined. Most of the habitat in which the turkeys were released were unsuitable and in late fall some of the birds became an agricultural nuisance since their survival depended on farm visits. In October of 1992, a young tom was live captured. In March of 1993, five more birds were shot and frozen before submission to the laboratory. A young female was also live captured and in April of 1993 and a second female in June. We blood tested these birds for Salmonella pullorum and used a choanal swab for Mycoplasma cultures. The live birds were kept for observation and no clinical signs were observed. The local poultry industry was informed in the fall of 1992 of this release and was warned not to allow these wild turkeys onto their premises since they had an unknown disease status. The three birds submitted live tested negative for Salmonella pullorum, but a rapidly growing Mycoplasma spp was isolated from the tom, one of the live hens and four of the five frozen birds. The isolate was sent to Guelph (Louise Ruhnke) where it was tested against avian isolates (Mg, Ms, Mm, Mi, M. gallopavonis, M. columbinasale, and M. gallinacaeum). From two birds, M. gallinacaeum was identified, but the other four isolates could not be identified. A large portion of Eastern wild turkey (up to 80%) is seropositive for M. gallopavonis. This strain has been shown to be lethal to chick and turkey embryos. We, therefore, wanted to establish the transmissibility and pathogenicity of our unknown isolate. In May of 1993, we had a collection of one wild tom that was Mycoplasma culture positive and two wild hens, which were Mycoplasma negative. To these we added a spent domestic bronze breeder hen, which was also Mycoplasma negative. The birds were housed in an outside enclosure of about 12x20 feed with a shelter. They shared a water and feed bucket. In July, all four turkeys were recultured with the following results: The male was still positive. The hen added in early spring remained negative while the domestic hen and the second wild hen (added in June) became culture positive. Pathogeniticy Study Sixteen-day-old turkey poults were inoculated intratracheally with 0.1 ml of a Mycoplasma culture broth using two birds each for three concentrations. These were estimated by color change, but too concentrated to count at 15 μl aliquots. Four control birds were inoculated with the growth medium only.
Results There were no clinical signs. Birds were necropsied at 3, 5, and 12 days post inoculation. At 3 and 5 days post inoculation, there was lymphocytic interstitial pneumonia and bronchitis, but this lesion apparently resolved, as it was not observed at 12 days post inoculation. The control birds showed minor lymphocytic reactions, which can be expected in the avian lung.
Serology Culture positive birds gave a false positive agglutination test for Mg (HI negative), but not for Ms. One bird tested positive for Mm on rapid plate test.
Conclusion The unknown Mycoplasma species isolated from Eastern wild turkeys is horizontally transmitted, causes no clinical signs and is essentially non-pathogenic for two-three weeks old domestic turkey poults. Its affect on other domestic or wild birds is unknown. The isolate may cross react with Mg plate agglutination and interfere with screening tests of commercial poultry.
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