Exploration of lymphoproliferative disease virus strains in wild turkeys (Meleagris gallopavo) in Iowa, USA

Wild turkeys (Meleagris gallopavo) were nearly extirpated in the early 1900's and extensive restoration efforts utilizing translocated wild turkeys were employed to restore populations. Although these efforts were successful, populations have again been in decline due to unknown causes. Lymphoproliferative disease virus (LPDV) was first detected in the United States in 2009. The coinciding appearance of LDPV and declining populations have led to studies in several states and provinces in North America to characterize its prevalence and distribution due to concerns about its potential role in population declines. The spread of disease agents is a common outcome during translocation programs and could be related to the spread of LPDV. Prior studies have performed phylogenetic analyses to examine genetic variation across and geographic clustering among strains. In this study we aimed to identify the diversity of LPDV strains present in wild turkeys in Iowa and if there was geographic clustering within the state or with other locations where LPDV has been detected. We sequenced a subset (n = 77) of hunter-harvested samples covering eight of the nine agricultural regions in Iowa that tested PCR positive with the viral gag gene. We performed phylogenetic analysis on 73 unique Iowan strains as well as previously catalogued strains from other regions retrieved from the National Center for Biotechnology Information (NCBI) GenBank database. Overall, Iowa strains did not show geographic clustering within the state or with any other specific geographic regions. Our study demonstrated that there is a high level of genetic diversity among LPDV strains in Iowa and did not provide evidence of connection with a particular location external to Iowa as a source of introduction of LPDV to the state.