Infectious Disease Survey of Rio Grande Wild Turkeys in the Edwards Plateau of Texas

Abstract

State wildlife agencies have translocated thousands of wild turkeys (Meleagris gallopavo) since the 1930s to reestablish this species. Because of threats to the domestic poultry industry and wild birds, screening for selected infectious agents has become routine since the early 1980s. One of the principal sources for Rio Grande wild turkeys (M. gallopavo intermedia) for translocation purposes was the Edwards Plateau of Texas (USA). Unfortunately, turkey abundance has declined in the southern Edwards Plateau since the late 1970s. Surprisingly few studies have addressed wild turkeys in this region, perhaps reflecting its status as the heart of Rio Grande turkey range. We surveyed 70 free-living Rio Grande wild turkeys from Bandera and Kerr counties, Texas, for evidence of exposure to Salmonella typhimurium, S. pullorum, Mycoplasma gallisepticum, M. meleagridis, M. synoviae, Chlamydophila psittaci, and the avian influenza, Newcastle disease, turkey corona, and reticuloendotheliosis viruses. Of these, 80% (56) were seropositive for both M. gallisepticum and M. synoviae on the serum plate antigen test. Ten of these individuals (14% of total) were positive for M. synoviae by hemagglutination inhibition testing. All other serologic tests were negative. Two adult females sampled in Kerr County, whose body mass was significantly less than that of other adult females trapped in the area, tested positive for reticuloendotheliosis virus (REV) proviral DNA on polymerase chain reaction. Reticuloendotheliosis virus was isolated from one of these individuals. The pathogenesis, transmission, and/or population-level influences of M. gallisepticum, M. synoviae, and REV in Rio Grande wild turkeys deserves further study.

Impacts of poultry vaccination on viruses of wild bird

“…The initial dissemination of REV, which appears to have originated as a mammalian virus transmitted into birds during experimental passage of a model Plasmodium species in ducks [27 ], has its origins in contamination of both fowlpox virus (FPV) and MDV vaccines, with extensive dissemination particularly linked to integration of the REV genome into the genome of FPV vaccine strains. Thus infection and disease associated with REV in wild birds, including wild turkeys [30,31], can be presumed to have been derived from contamination in vaccines.…”

Flooding-induced landscape changes along dendritic stream networks and implications for wildlife habitat

“…The Edwards Plateau of Texas traditionally was considered excellent habitat for wild turkeys (Beasom and Wilson, 1992), and directly or indirectly served as the source for most translocations of this subspecies (Peterson et al, 2002). Beginning in the late 1970s, however, wild turkey abundance declined in the southeastern portion of the Plateau while it exhibited no long-term changes in population trends elsewhere in this physiographic region (Randel et al, 2005;Schaap et al, 2005;Collier et al, 2007;Randel et al, 2007).…”

“…The first efforts to restore wild turkey populations in Texas were taken by the state's legislature in 1881 (Beasom and Wilson, 1992). Over time, restocking proved to be one of the most effective strategies (Beasom and Wilson, 1992), with most birds originating directly or indirectly from remnant flocks in semi-arid rangelands used for livestock grazing from the Edwards Plateau and South Texas (Peterson et al, 2002).…”

“…The reasons for this decline remain unclear. Possible factors include habitat changes (Hubbard et al, 1999), increased human population (Beasom and Wilson, 1992), decreased availability of foraging resources (Thogmartin, 2001), and predation, disease, and natural disturbances (Peterson et al, 2002).…”

Detection of reticuloendotheliosis virus by immunohistochemistry andin situhybridization in experimentally infected Japanese quail embryos and archived formalin-fixed and paraffin-embedded tumours

“…Additional non-defective REV strains have been isolated from geese, pheasants, peafowl, Japanese quail, Greater prairie chickens (Tympanuchus cupido pinnatus), and Attwater's prairie chickens (Tympanuchus cupido attwateri). Natural or experimentally induced reticuloendotheliosis, an oncogenic and immunosuppressive disease, has also been reported in a variety of wild birds (Ley et al, 1989;Hayes et al, 1992;Peterson et al, 2002;Witter & Fadly, 2003;Zavala et al, 2006;Barbosa et al 2007a,b).…”