Iowa Wild Turkeys Carry Diverse LPDV Strains Without a Clear Geographic Pattern
Wild turkeys in Iowa are now part of a much larger story than harvest numbers alone. A molecular survey of lymphoproliferative disease virus in hunter-harvested birds found substantial genetic diversity across the state, but no evidence that the virus strains clustered by county, agricultural region, or any single external source of introduction.
The findings matter because Iowa sits inside a broader restoration history that reshaped wild turkey populations across North America. After near extirpation in the early 1900s, wild turkeys were re-established through large-scale translocation programs. Those efforts succeeded, but they also created the conditions in which infectious agents can move along with relocated birds. LPDV, first detected in the United States in 2009, has been under close watch ever since because its emergence overlaps with renewed population declines in multiple states.
This study focused on whether Iowa’s virus strains showed a geographic signature that might point to a local introduction route or a more limited spread pattern. The answer was no. Instead, the sequence data pointed to a broad and mixed viral population already established across the state.
Sequencing 77 Positive Samples Across Iowa
Investigators collected tarsi from hunter-harvested wild turkeys between 2019 and 2021, and also included a small number of road-killed birds and diagnostic submissions from the Iowa Department of Natural Resources. In total, 1,022 turkeys were sampled for the broader surveillance effort. From that pool, 77 samples that tested PCR positive for the viral gag gene were sequenced, spanning eight of Iowa’s nine agricultural regions.
The laboratory workflow was designed to reduce contamination risk at each step. Bone marrow was removed with sterilized instruments, DNA was extracted with a commercial kit, and samples were processed into standardized working concentrations before downstream analysis. The study design reflects a practical surveillance question rather than an experimental challenge: if LPDV is present in Iowa, how many strain types are circulating, and do they point to a single origin?
The sequencing effort identified 73 unique Iowa strains. That number alone signals a virus with substantial local variation rather than a uniform lineage moving through the state in a single wave.
No Evidence of Statewide or External Clustering
Phylogenetic analysis did not show Iowa strains grouping by geography within the state. Birds from different areas were not arranged into neat regional clusters, and the sequences also failed to align with any one outside location as a likely source of introduction. In plain terms, the virus did not behave like a single imported strain spreading outward from one identifiable point on the map.
The absence of clustering does not mean the virus is harmless. It means the evolutionary signal is complicated, with multiple related lineages circulating across Iowa rather than one dominant genetic track. For wildlife disease surveillance, that pattern makes source tracing far more difficult.
It also weakens any simple explanation that ties the current Iowa situation to one recent introduction event. The data do not support a connection to a particular geographic origin external to Iowa.
Why LPDV Draws Concern in Restored Turkey Populations
LPDV is an oncogenic exogenous avian retrovirus first identified in domestic turkeys outside North America. In wild turkeys, infection is often clinically silent in hunter-harvested birds, although not always. When signs do appear, they tend to be nonspecific. That makes field detection difficult and leaves molecular surveillance as one of the few reliable ways to track the virus in free-ranging populations.
The biology of the virus fits the surveillance concern. Prior work has suggested horizontal transmission is possible, and prior phylogenetic studies have already shown that LPDV is not confined to one narrow region. Earlier analyses found two major clades, with one grouping linked to the Israeli prototype and another to North American strains. Other studies identified complex patterns across the United States and Canada, including clusters that crossed geographic boundaries in ways consistent with translocation history.
Iowa’s restoration history makes that background especially relevant. The state relied on birds moved from Missouri and later from re-established Iowa populations to rebuild its turkey numbers. Wildlife translocation can restore a species and still move pathogens at the same time. The current study does not prove that restoration efforts introduced LPDV into Iowa, but it places the virus inside a framework where historical movement of birds remains a plausible contributor to its wider spread.
What the Iowa Data Add to the Broader LPDV Picture
The main contribution of this study is not a single dramatic outbreak signal. It is the demonstration of high genetic diversity in a midwestern population where the virus had not been mapped in this level of detail before. Eight of Iowa’s nine agricultural regions were represented, and the sequences did not sort into localized groups. That pattern fits a virus that has been present long enough, and moved often enough, to blur the geographic footprints that epidemiologists usually look for.
From a surveillance perspective, that creates a practical problem. When a pathogen shows little spatial structure, traditional assumptions about nearby birds sharing closely related strains become less useful. Management teams then need broader sampling and more complete sequence data to understand whether the virus is being maintained locally, repeatedly introduced, or both.
The study also reinforces a point that matters beyond Iowa. Wild turkey restoration remains one of North America’s major conservation successes, yet pathogen monitoring has to move alongside those efforts. A recovered population can still carry the legacy of earlier translocations, and a virus with broad genetic diversity can persist without producing obvious clinical warning signs in the field.
Surveillance Will Need Wider Genomic Coverage
The current findings stop short of identifying a source for LPDV in Iowa, and they do not link the virus to a single restoration event or a single outside region. What they do show is a statewide population of genetically varied strains with no clear geographic sorting.
For future work, that leaves a narrower but important task: expanding genomic surveillance across more sites and more time points to determine whether the observed diversity reflects longstanding circulation, repeated introductions, or both. The present dataset establishes the baseline. It does not settle the question of how the virus entered Iowa, and it does not explain whether the strain diversity has changed over time.