Regional Pathogen Surveillance of Free-Ranging Wild Turkeys (Meleagris gallopavo) in North Carolina, USA.

Abstract

Wild Turkeys (Meleagris gallopavo, hereafter turkeys), an important North American game species, have experienced declines throughout their eastern range. Growing concern over turkey population sustainability has renewed interest in investigating potential disease threats. We conducted pathogen surveillance in turkeys in three North Carolina, USA ecoregions-Mountains, Piedmont, and Coastal Plain-in 2020-22 to provide baseline data relevant to the southeastern USA. We collected samples from 586 live free-ranging turkeys plus 22 recaptured individuals (n=608: 194 males, 414 females; 159 juveniles, 449 adults) to test for exposure to or infection with selected pathogens. Molecular testing revealed infections with Haemoproteus spp. (57%), lymphoproliferative disease virus (LPDV; 46.8%), Mycoplasma spp. (39.8%), Leucocytozoon spp. (8.8%), and reticuloendotheliosis virus (REV; 3.4%). We detected antibodies to Toxoplasma gondii (21.3%), West Nile virus (WNV; 15.4%), and avian influenza virus (2.0%). No turkey coronavirus, Plasmodium, Borrelia, or Salmonella infections were detected. There were no prevalence differences between sexes, except for REV (females=5%, males=1%). Prevalence was higher in adults than in juveniles for LPDV (adult=52%, juvenile=33%), WNV (adult=19%, juvenile=6%), Haemoproteus (adult=60%, juvenile=49%), T. gondii (adult=24%, juvenile=14%), and Leucocytozoon (adult=11%, juvenile=3%). Prevalence of LPDV differed significantly across ecoregions, with the highest prevalence in the Piedmont (62%), followed by the Mountains (51%) and the Coastal Plain (27%). Prevalence of WNV antibodies was higher in the Piedmont (24%) than in the Mountains (8%). Haemoproteus and Leucocytozoon prevalence increased over a regional gradient, with detections of 24% and 0% in the Mountains, 65% and 6% in the Piedmont, and 85 and 21% in Coastal Plain, respectively. Mycoplasma spp. prevalence was higher in the Mountains (45%) and the Coastal Plain (47%) than in the Piedmont (27%). Our data highlighted sex-, age-, and region-based differences in prevalence for several pathogens, thereby enabling managers to tailor management strategies and researchers to investigate effects of these pathogens on turkey survival and movement.