Lymphoproliferative Disease Virus and Reticuloendotheliosis Virus Detection and Disease in Wild Turkeys ( Meleagris gallopavo ) Kayla G. Adcock, 1,6 Roy D. Berghaus, 2 Chloe C. Goodwin, 1,3 Mark G. Ruder, 1 Michael J. Yabsley, 1,4,5 Daniel G. Mead, 1 and Nicole M. Nemeth 1,3,6 1 Southeastern Cooperative Wildlife Disease Study, University of Georgia, 589 D.W. Brooks Drive, Athens, Georgia 30602, USA 2 Department of Population Health, University of Georgia, 501 D.W. Brooks Drive, Athens, Georgia 30602, USA 3 Department of Pathology, University of Georgia, 501 D.W. Brooks Drive, Athens, Georgia 30602, USA 4 Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, 180 E. Green Street, Athens, Georgia 30602, USA 5 Center for Emerging Infectious Diseases, University of Georgia, 140 E. Green Street, Athens, Georgia 30602, USA 6 Corresponding author (emails: kjg@uga.edu, nmnemeth@uga.edu) ABSTRACT : Lymphoproliferative disease virus (LPDV) and reticuloendotheliosis virus (REV) are oncogenic retroviruses that can cause disease in wild and domestic fowl. Lymphoproliferative disease virus infections are common and widespread in Wild Turkeys ( Meleagris gallopavo ) in the US and east-central Canada, while REV has been detected worldwide in numerous avian host species. We tested tissues (spleen, liver, and/or bone marrow, plus neoplastic tissue, if present) from 172 Wild Turkeys that underwent necropsy from December 2018 through October 2021 for both viruses using PCR. We evaluated demographic, geographic, temporal, and seasonal data by chi-square test of independence and logistic regression for turkeys infected with LPDV and/or REV. At least one of these retroviruses was detected in 80.8 % (139/172) of Wild Turkeys from 15 US states, with significantly more turkeys being positive for LPDV (72.1 % , 124/172) versus REV (43.6 % , 75/172; P , 0.001). Both viruses (coinfections) were detected in 34.9 % (60/172) of turkeys. Among LPDV-infected turkeys (including coinfections), bone marrow had the highest detection rate (38/58, 65.5 % ), significantly higher than spleen (30/58, 51.7 % ) and liver (20/58, 34.5 % ; P , 0.001). In REV-infected turkeys, bone marrow had the highest detection rate (24/58, 41.4 % ). All three tissues (spleen, liver, bone marrow) concurrently tested positive in most (15/25, 60 % ) REV- infected turkeys. These results suggest LPDV tissue tropism for bone marrow, whereas REV may have broader tissue tropism. Histopathology consistent with lymphoid proliferation and/or neoplasia characteristic of lymphoproliferative disease was evident in 29/172 (16.9 % ) turkeys assessed, including two REV-only–infected turkeys. Season was significantly associated with LPDV prevalence (highest in winter); year and season were both significantly associated with REV prevalence (highest in 2020 and winter). These data contribute to optimizing diagnostic strategies that may aid in pathogen monitoring and improve detections to increase our understanding of the potential impacts of these viruses on Wild Turkey populations. Key words: Coinfection, lymphoproliferative disease virus, Meleagris gallopavo , neoplasia, reticulo- endotheliosis virus, retrovirus, Wild Turkey. INTRODUCTION The Wild Turkey ( Meleagris gallopavo ) is a popular game species and conservation icon in North America (Baumann et al. 1990). By the early 1900s, drastic declines led to extirpation of some populations due to habitat degradation, overhunting, and disease; restoration efforts in the US and Canada involved translocation via trap and transfer programs (Eriksen et al. 2015). Although some populations reestablished, more recent declines in some regions have caused concern over possible disease impacts (Byrne et al. 2015; Casalena et al. 2015; Eriksen et al. 2015; Pollentier et al. 2021). Further, translocations introduced naı ̈ve populations to new environments, potentially facilitating pathogen introduction or spillover between introduced and established Wild Tur- keys and other wild avian species, as well as between wild and domestic turkeys (MacDon- ald et al. 2019b; Stewart et al. 2019; Caleiro et al. 2020). Finally, reduced habitat availabil- ity and quality may indirectly facilitate disease among wildlife (Stauffer et al. 2017), which 139 DOI: 10.7589/JWD-D-23-00012 Journal of Wildlife Diseases , 60(1), 2024, pp. 139–150 Ó Wildlife Disease Association 2024 Downloaded from https://jwd.kglmeridian.com at 2026-05-01 via free access may also then be more concentrated on the landscape, fueling transmission. Because of increased opportunities for patho- gen transmission among wild and domestic tur- keys and other wild birds, it is important to assess pathogen prevalence in Wild Turkey populations. Two oncogenic avian retroviruses, lymphoproliferative disease virus (LPDV) and reticuloendotheliosis virus (REV), have varied virulence with subclinical to fatal outcomes (Allison et al. 2014; Thomas et al. 2015). Detec- tions of LPDV are widespread in Wild Turkeys, including in Ontario, Manitoba, and Quebec, Canada; the eastern US; and historically in domestic turkeys in Israel and England (Ianco- nescu et al. 1972; Biggs et al. 1978; Thomas et al. 2015; Alger et al. 2017; MacDonald et al. 2019a, 2019b; Cox et al. 2022; Shea et al. 2022). Lymphoproliferative disease virus infection may lead to immunosuppression and cachexia con- current with lymphoid neoplasia, which may predispose birds to severe secondary infections (Niedringhaus et al. 2019) and has been associated with mortality in Wild Turkeys (Allison et al. 2014). Similar to LPDV, REV can cause lymphoproliferative disease (LPD), with similar clinicopathologic manifestations (Ley et al. 1989; Niedringhaus et al. 2019). Reticulo- endotheliosis virus is globally distributed, with associated fatal disease documented in wild tur- keys in North Carolina and Georgia, US, and detections in Texas, US, and Brazil, and in other avian species in Brazil and China (Ley et al. 1989; Hayes et al. 1992; Thomas et al. 2015; Stewart et al. 2019; Caleiro et al. 2020; Liu et al. 2020; Shi et al. 2021). Thus far, comparisons of LPDV and REV detection in Wild Turkeys across broader regions of North America are lacking but are necessitated by unknown popu- lation health implications of these viruses. Our study aimed to compare infection and coinfection prevalence of LPDV and REV in Wild Turkeys from throughout the US from December 2018 to October 2021. Spleen, liver, and bone marrow have been deemed diagnosti- cally relevant tissues for LPDV detection in Wild Turkeys, although the singular best tissue for LPDV detection has not been assessed (Allison et al. 2014) and is similarly unknown for REV. Therefore, we also assessed and compared viral DNA tissue tropism of LPDV and REV to determine the most diagnostically relevant tissue sample(s). We also described associated pathol- ogy (lymphoid proliferation or neoplasia) attri- buted to these two retroviruses. We evaluated the relationships between LPDV infection and/or REV infection and demographic, geographic, temporal, and seasonal patterns, and docu- mented additional coinfecting pathogens. MATERIALS AND METHODS Sample collection and processing Field-collected Wild Turkey carcasses ( n ¼ 115) and tissues ( n ¼ 57) were submitted to the South eastern Cooperative Wildlife Disease Study (SCWDS) for diagnostic evaluation. Turkeys were either found dead, observed to be ill and subse- quently died naturally, dispatched because of clin- ical illness or illegal possession, hunter harvested, or predator killed. Necropsy and histopathologic exam- ination were performed on carcasses, with ancillary tests as needed for diagnoses. Tissues of all organ systems were preserved in 10 % neutral buffered formalin for 48 h, routinely trimmed, embedded in paraffin, sectioned (4 m m) and stained with H&E at an American Association of Veterinary Labora- tory Diagnosticians–accredited laboratory (Athens Veterinary Diagnostic Laboratory [AVDL], Athens, Georgia, USA). Tissues were subjectively assessed for lymphoid proliferation (beyond that expected for disseminated, nodular lymphoid tissue) and neo- plasia, based on severity, anatomic and histologic distribution, and pattern of mononuclear, primarily lymphocytic, cell invasion. Those with lesions within this spectrum were considered to have LPD (Alli- son et al. 2014; Niedringhaus et al. 2019). DNA extraction Postcollection, samples were stored in cryovials at 4 C for 24–48 h until extraction. Approximately 0.5-cm 3 samples of select tissues were collected for nucleic acid extraction using the Qiagen DNeasy Blood and Tissue Kit (Qiagen, German- town, Maryland, USA) per manufacturer’s proto- col. In addition, spleen, liver, and bone marrow were each tested individually from 58 turkeys 140 JOURNAL OF WILDLIFE DISEASES, VOL. 60, NO. 1, JANUARY 2024 Downloaded from https://jwd.kglmeridian.com at 2026-05-01 via free access based on LPDV and REV tropism for hematopoi- etic tissues in domestic turkeys (Allison et al. 2014). LPDV PCR Proviral DNA for LPDV was detected using primers targeting a 431-nucleotide portion of the gag polyprotein (partial p31/partial CA; 5 0 -ATGAG GACTTGTTAGATTGGTTAC-3 0 , 5 0 -TGATGGCG TCAGGGCTATTTG-3 0 ; Allison et al. 2014). GoTaq w Flexi DNA polymerase system (Prom- ega, Madison, Wisconsin, USA) was mixed in a 50- m L total PCR reaction with 2 l L of template and the following reagents: 10 m L of 5X Green GoTaq Flexi Buffer (1X), 3 m L MgCl 2 solution (1.5 mM), 2.5 m L dNTPs (0.5 m M), 0.5 m L of each primer (0.5 m M), 0.15 m L of GoTaq DNA poly- merase (0.75 units), and 31.35 m L of nuclease- free water (Promega). Thermocycling conditions for PCR amplification were 94 C for 2 min; 45 cycles of 94 C for 45 s, 50 C for 1 min, and 72 C for 1 min; followed by 72 C for 1 min and a 4 C hold. Positive (Wild Turkey tissue) and negative controls were included. REV PCR Proviral DNA for REV was detected using prim- ers targeting a 291-nucleotide portion of the long terminal repeat spanning the entire unique 5 0 repeat region and 118 nucleotides of the unique 3 0 region (5 0 -CATACTGGAGCCAATGGTT-3 0 , 5 0 -AA TGTTGTACCGAAGTACT-3 0 ; Davidson et al. 1995). GoTaq Flexi DNA polymerase system (Promega) was mixed in a 21.5 m L total PCR reac- tion with 1.5 m L of template and the following reagents: 3 m L of 5X Green GoTaq Flexi Buffer (0.6X), 1 m L MgCl 2 solution (1.1 mM), 0.5 m L dNTPs (0.2 m M), 1 m L of each primer (2.2 m M), 0.25 m L of GoTaq DNA polymerase (1.25 units) and 13.25 m L of nuclease-free water (Promega). Thermocycling conditions for PCR amplification were 95 C for 5 min; five cycles of 95 C for 30 s, 58.5 C for 30 s, and 72 C for 1 min; 30 cycles of 95 C for 30 s, 58.5 C for 30 s, and 72 C for 1 min 50 s; followed by 72 C for 10 min, and a 10 C hold. Posi- tive (Wild Turkey tissue) and negative controls were included. Gel electrophoresis Gel electrophoresis of PCR products was per- formed on a 2 % agarose gel with ethidium bromide (Bio-Rad Laboratories, Hercules, California, USA) at 0.5 m g/mL in 1X concentration of Tris Acetate– EDTA buffer solution (Sigma-Aldrich, Saint Louis, Missouri, USA). Amplicons were visualized with an ultraviolet transilluminator. Samples with appropri- ately sized complementary DNA present on gel electrophoresis were considered positive. Ancillary diagnostic testing Avipoxvirus infection was suspected in turkeys with gross proliferative skin lesions in nonfeath- ered or sparsely feathered skin of the head, neck, or legs, as confirmed by histopathology (Niedring- haus et al. 2019). Bacterial infections were diag- nosed by gross or histopathologic evidence of inflammation or necrosis with intralesional bacte- ria, with confirmation by aerobic bacterial culture using standard protocols at AVDL. Grossly or microscopically detected parasites were identified morphologically by broad taxonomic category (i.e., nematode, cestode, trematode; Gardiner and Poyton 2006). Detection of intracellular parasites was determined by PCR and a modified aggluti- nation test (Hayes et al. 2003; Hellgren et al. 2004; Dubey 2010; Cabral et al. 2021). Virus iso- lation was performed on pooled tissues (brain, heart, and kidney) for select cases as described (Kunkel et al. 2021). Statistical analyses Year, season, region, sex, and age were assessed to determine whether they were associated with viral detection. Season was according to equinox and solstice dates for the northern hemisphere; US region was categorized as “Northeast” for tur- keys from Pennsylvania, Kentucky, and West Virginia, “Southeast” for turkeys from Georgia, Mississippi, North Carolina, Tennessee, Louisi- ana, Florida, Alabama, South Carolina, and “West” for turkeys from Kansas, Arkansas, Mis- souri, and Oklahoma; and age was juvenile/poult if , 1 yr posthatch and adult if 1 yr. Univariable associations (for year, season, region, sex and age) with virus detection prevalences were evaluated using a chi-square test of independence. Multi- variable associations with virus detection preva- lences were evaluated using logistic regression. Multivariable model selection was performed using a manual backward stepwise approach beginning with a maximum model that contained all variables that were associated ( P , 0.2) with virus detection in the univariable analysis. ADCOCK ET AL.—RETROVIRUS DETECTION AND DISEASE IN WILD TURKEYS 141 Downloaded from https://jwd.kglmeridian.com at 2026-05-01 via free access Predictors were removed from the multivariable model one by one based on their significance until only variables having P , 0.05 remained. The marginal proportions of Wild Turkeys with posi- tive results for LPDV and REV were compared using McNemar’s test. The proportions of turkeys with virus detected in paired samples of different tissue types were compared using generalized estimating equations (GEE) logistic regression with bird included as a clustering variable to account for repeated measurements on the same turkey. Robust standard errors and an exchange- able working correlation structure were used to generate GEE models. Pairwise comparisons were performed using the Bonferroni procedure to limit the type I error probability to 5 % over all comparisons. All tests assumed a two-sided alter- native hypothesis and were considered statistically significant if P , 0.05. Analyses were performed using Stata version 17.0 (StataCorp LLC, College Station, Texas, USA). RESULTS Demographic, seasonal, and geographic data All retrovirus-positive Wild Turkeys ( n ¼ 139) were evaluated for demographic, temporal, and geographic associations. Male and female tur- keys were evenly distributed at 50.0 % (60/120 each; sex was unknown in 19). Most (85.5 % ; 112/131) were adults, with 13.7 % (18/131) juve- niles and 0.7 % (1/131) poults (age was unknown for eight). For retrovirus-positive turkeys, 24.5 % (34/139) were collected in winter (December– February), 21.6 % (30/139) in spring (March– May), 24.5 % (34/139) in summer (June–August), and 29.5 % (41/139) in fall (September–Novem- ber). Turkeys in which retrovirus infections were detected originated in the Northeast (46.8 % ; 65/139), the Southeast (46.0 % ; 64/139), and the West (7.2 % ; 10/139; Fig. 1). F IGURE 1. Map showing states with counties where lymphoproliferative disease virus (LPDV, black), reticu- loendotheliosis virus (REV, light gray) and coinfections (medium gray) were detected by PCR in Wild Turkeys ( Meleagris gallopavo ) from the USA (December 2018 to October 2021). Some coinfected counties include LPDV-only and/or REV-only–infected turkeys as well, but for simplicity were depicted as coinfections because both viruses were detected. 142 JOURNAL OF WILDLIFE DISEASES, VOL. 60, NO. 1, JANUARY 2024 Downloaded from https://jwd.kglmeridian.com at 2026-05-01 via free access Clinical signs and gross findings Of the 139 turkeys from which retroviruses were detected, manner of death was reported in 124 cases as follows: 17 (13.7 % ) died natu- rally after being witnessed alive, 61 (49.2 % ) were dispatched because of illness, 33 (26.6 % ) were found dead, 10 (8.1 % ) were hunter har- vested, and three (2.4 % ) died because of domestic canine predation. Clinical signs (e.g., ataxia, lethargy, reduced mobility, reduced fear of humans, skin abnormalities) were evident in 87/97 (89.7 % ). Of 91 evaluated carcasses, nutritional condition ranged from emaciated to excellent, with 69.2 % (63/91) in a poor or emaciated condition. Gross skin lesions (i.e., proliferative nodules) and splenomegaly were observed in 35.1 % (39/111) and 4.5 % (5/111), respectively. Twelve Wild Turkeys had gross lesions consistent with LPD in other organs, including liver ( n ¼ 5); kidney ( n ¼ 3); heart, lung, spleen, crop, proventriculus, and subcu- tis ( n ¼ 2 each); and uterus and cecum ( n ¼ 1 each). Retrovirus prevalence with seasonal, temporal, and demographic associations Samples from 172 Wild Turkeys collected from 2018 through 2021 were tested for LPDV and REV by PCR. At least one retrovi- rus was detected in 80.8 % (139/172). The percentage of birds with LPDV detection (124/172; 72.1 % ) was significantly higher than that with REV detection (75/172; 43.6 % ; McNemar’s test, P , 0.001). Both LPDV and REV were detected in 60/172 (34.9 % ) turkeys; only LPDV was detected in 64/172 (37.2 % ) turkeys; only REV was detected in 15/172 (8.7 % ) turkeys; neither virus was detected in 33/172 (19.2 % ) turkeys (Table 1). Univariable associations with LPDV and REV prevalences are provided in Table 2. Only season was sig- nificantly associated with LPDV prevalence in the univariable analysis ( P ¼ 0.027), while REV prevalence was associated with year ( P ¼ 0.010), season ( P ¼ 0.001) and sex ( P ¼ 0.036). In the multivariable analysis, REV prevalence was sig- nificantly associated with year and season, but not sex (Table 3). Compared with samples sub- mitted in 2018–19, the odds of detecting REV were 1.7 times higher in 2020 and 0.63 times as high (37 % lower) in 2021, after adjusting for season. Compared with samples submitted in winter, the odds of detecting REV were low- ered by 78 % in spring, 65 % in summer and 27 % in fall, after adjusting for year. Coinfections Additional pathogens were detected through diagnostic investigations in the 139 Wild Tur- keys with retrovirus infections. Poxviral disease was diagnosed in 39 (28.1 % ) of these. Bacterial infections were diagnosed in 36 (25.9 % ) Wild Turkeys and were most commonly attributed to Escherichia coli (8/36) and Staphylococcus spp. (7/36). Parasites (metazoa and protozoa) were observed in 44 (31.7 % ) cases; some had both parasite types. For metazoa, both nematodes and cestodes were recorded in seven cases, nematodes only in 18, and cestodes only in four. The most common protozoans detected were Histomonas meleagridis (9/26), Sarcocystis spp. (7/26), and Toxoplasma gondii (4/26). Virus iso- lation on tissues from 11 turkeys yielded no isolations. T ABLE 1. Lymphoproliferative disease virus (LPDV), reticuloendotheliosis virus (REV), and LPDV-REV coinfection prevalence as determined by PCR test in 172 Wild Turkeys ( Meleagris gallopavo ) submitted for diagnostic evaluation to the Southeastern Cooperative Wildlife Disease Study from December 2018 to October 2021. Total % including coinfections (No. positive/total) Single virus % (No. positive/total) LPDV 72.1 (124/172) 37.2 (64/172) REV 43.6 (75/172) 8.7 (15/172) LPDV and REV coinfection 34.9 (60/172) — ADCOCK ET AL.—RETROVIRUS DETECTION AND DISEASE IN WILD TURKEYS 143 Downloaded from https://jwd.kglmeridian.com at 2026-05-01 via free access Retroviral tissue tropism In LPDV-infected Wild Turkeys (including those coinfected with REV), bone marrow most commonly tested positive (102/104; 98.1 % ). Similarly, in REV-infected turkeys (including those coinfected with LPDV), bone marrow most commonly tested positive (22/57; 38.6 % ). Among the 58 birds for which all three target tissues (spleen, liver, bone marrow) were indi- vidually tested, all three tissues tested positive in 15/25 (60.0 % ) REV-infected turkeys and 19/40 (47.5 % ) LPDV-infected turkeys. Among individually tested spleen, liver, and bone marrow ( n ¼ 58; Fig. 2, Table 4, and Sup- plementary Material Table S1), percentages of each tissue that tested positive differed sig- nificantly for LPDV ( P , 0.001) and REV ( P ¼ 0.008). The percentage of birds with LPDV detected in bone marrow was significantly higher than spleen, which was significantly higher than liver. The percentage with REV detected in bone marrow was significantly higher than liver; the percentage with REV detected in spleen did not differ significantly from the other two tissue types (Table 4). Histopathology Characterized by histologic evidence of proliferative or neoplastic mononuclear cell, primarily lymphoid, infiltrates, LPD was diag- nosed in 29/139 (20.9 % ) turkeys in which LPDV and/or REV was detected (Fig. 3). The percentages of turkeys diagnosed with LPD did not significantly differ among those in which both viruses were detected (13/60, 21.7 % ), only LPDV was detected (14/64, T ABLE 2. Univariable associations with lymphoproliferative disease virus (LPDV) and reticuloendothelial disease virus (REV) detection prevalences in 172 Wild Turkeys ( Meleagris gallopavo ) submitted for diagnostic evaluation to the Southeastern Cooperative Wildlife Disease Study from December 2018 to October 2021. LPDV REV Variable No. positive/No. samples ( % ) P a No. positive/No. samples ( % ) P a Year 2018–19 2020 2021 33/47 (70.2) b 48/64 (75.0) b 43/61 (70.5) b 0.81 21/47 (44.7) bc 36/64 (56.3) c 18/61 (29.5) b 0.010 Season Winter Spring Summer Fall 30/36 (83.3) c 27/48 (56.3) b 33/42 (78.6) bc 34/46 (73.9) bc 0.027 19/36 (52.8) cd 12/48 (25.0) b 15/42 (35.7) bc 29/46 (63.0) d 0.001 Region Northeast Southeast West 60/77 (77.9) b 56/81 (69.1) b 8/14 (57.1) b 0.20 33/77 (42.9) b 38/81 (46.9) b 4/14 (28.6) b 0.44 Sex e Female Male 54/71 (76.1) b 53/77 (68.8) b 0.33 38/71 (53.5) c 28/77 (36.4) b 0.036 Age e Adult Juvenile/poult 101/143 (70.6) b 15/20 (75.0) b 0.69 64/143 (44.8) b 10/20 (50.0) b 0.66 a Chi-square test P -value. b,c,d Within columns, category percentages with a superscript in common do not differ with a level of significance of 5 % over all comparisons. e Information on sex and age was only recorded for 148 and 163 birds, respectively. 144 JOURNAL OF WILDLIFE DISEASES, VOL. 60, NO. 1, JANUARY 2024 Downloaded from https://jwd.kglmeridian.com at 2026-05-01 via free access 21.9 % ), and only REV was detected (2/15, 13.3 % ; v 2 test, P ¼ 0.75). Histopathology was evaluated for LPD in 29 birds (14 with only LPDV detected; 13 with LPDV and REV detected; two with only REV detected). Tissue types varied significantly with respect to the percentage of birds that had abnormal proliferation of predominantly lymphoid cel- lular infiltrates ( P , 0.001; Supplementary Material Table S2). Skin, gastrointestinal tract, and heart, followed by liver and lung, were the most commonly affected tissues. DISCUSSION Multidecade population declines in por- tions of the Wild Turkey range have led to concern regarding potential health impacts of pathogens (Byrne et al. 2015; Eriksen et al. 2015), such as LPDV and REV. We detected both of these retroviruses, which also can infect domestic galliforms (Biggs et al. 1978), at high prevalence (72 % for LPDV; 44 % for REV) in Wild Turkeys across a large US region. These results are similar to those in New York, US, but contrast with those in Ontario, Canada, and in Maine and Texas, US, in which concurrent testing for LPDV and REV revealed lower prevalences: 65 % and 4 % for Ontario; 59 % and 16 % for Maine; and 4 % and 4 % for Texas (Alger et al. 2015; MacDonald et al. 2019a; Cox et al. 2022; Shea et al. 2022). Additionally, in our study over 80 % of Wild Turkeys were infected with one or both viruses and approximately F IGURE 2. Comparison of tissue tropism for lym- phoproliferative disease virus (black) and reticuloen- dotheliosis virus (gray) by PCR in Wild Turkeys ( Meleagris gallopavo ) from the USA (December 2018 to October 2021). Only turkeys from which individual spleen, liver, and bone marrow samples were concur- rently tested ( n ¼ 58) are included. T ABLE 3. Multivariable logistic regression model for the prediction of reticuloendotheliosis virus prevalence in 172 Wild Turkeys ( Meleagris gallopavo ) submitted to the Southeastern Cooperative Wildlife Disease Study from December 2018 to October 2021. Variable Coefficient (SE) Odds ratio (95 % confidence interval) P a Year 2018–19 2020 2021 Reference 0.54 (0.41) 0.46 (0.44) Reference 1.7 (0.76–3.8) 0.63 (0.27–1.5) 0.038 0.19 0.29 Season Winter Spring Summer Fall Reference 1.51 (0.46) 1.05 (0.46) 0.31 (0.47) Reference 0.22 (0.09–0.55) 0.35 (0.14–0.87) 0.73 (0.29–1.86) 0.004 0.001 0.024 0.52 Constant 0.41 (0.38) NA a Wald test P -value. ADCOCK ET AL.—RETROVIRUS DETECTION AND DISEASE IN WILD TURKEYS 145 Downloaded from https://jwd.kglmeridian.com at 2026-05-01 via free access 35 % were coinfected with LPDV and REV. This contrasts with Wild Turkeys sampled in Maine and Texas, in which coinfection preva- lences were 10 % and 0.5 % , respectively (Cox et al. 2022; Shea et al. 2022). Prevalence variation may be due in part to differing sam- ple sizes; sources of birds (e.g., sick or dead birds vs. hunter harvests and live captures); sample collection timing (e.g., seasonal vs. year-round), regional translocation histories; and geographic region size and location. Despite high prevalences of LPDV and REV infections in Wild Turkeys in numerous regions in the US and Canada, associated neo- plastic disease has been uncommonly docu- mented (Alger et al. 2015; Thomas et al. 2015; MacDonald et al. 2019b). For example, only 7 % of Wild Turkeys had evidence of lymphoid neoplasia among SCWDS diagnostic cases ( n ¼ 851) in a previous long-term study from 1980 to 2017 (Niedringhaus et al. 2019). In contrast, we detected a higher percentage of LPDV- and/or REV-infected Wild Turkeys with associated lymphoid disease (20.9 % of 139 birds) from 2018 to 2021. Higher disease prevalence in our study may be due to increased vigilance and interest in submitting sick and dead turkeys during the more recent study period or increased awareness by diagnos- ticians, or, alternately, it may reflect increased LPDV infections and thus LPD incidence in the study area. In our study, LPD-associated histopathology (lymphoid proliferation and/or lymphoid neoplasia) were most commonly observed in skin, gastrointestinal tract, and heart, followed by liver and lung. Further, ana- tomic distribution of LPD histopathology in our study is similar to previous research that docu- mented disseminated LPD involving skin, liver, heart, lung, brain, kidney, muscle, gastrointesti- nal tissues, and spleen (Niedringhaus et al. 2019). Additionally, we observed LPD histopa- thology in other tissues (adrenal gland, bone marrow, pancreas, uterus, ovary), reinforcing the notion that LPDV can cause severe, widely disseminated neoplasia in Wild Turkeys. Wild Turkeys with LPD that were infected with REV but not LPDV also had multiorgan neoplastic dissemination, involving brain, heart, lung, kid- ney, and liver. Our findings highlight the impor- tance of testing Wild Turkeys with evidence of lymphoid proliferation or neoplasia for both LPDV and REV, given that clinical signs, gross lesions, and histopathology can be similar for both viruses (Allison et al. 2014; Niedringhaus et al. 2019). Although similarities between LPDV and REV epidemiology are numerous, their avian host ranges differ greatly. In addition to Wild Turkeys, REV can infect and cause disease outbreaks in other wild and domestic species including the endangered Attwater’s Prairie Chicken ( Tympanuchus cupido attwateri ), domestic geese ( Anser anser domesticus ), layer hens ( Gallus gallus domesticus ), and domestic turkeys, with recent reemergence in yellow-chickens (a breed of domestic chickens) in Southern China and emergence in Muscovy Ducks ( Cairina moschata domes- ticus ) in China and Brazil and in Mallards T ABLE 4. Detection of lymphoproliferative disease virus (LPDV), reticuloendotheliosis virus (REV) in paired samples of spleen, liver, and bone marrow collected from 58 Wild Turkeys ( Melleagris gallipavo ) submitted to the Southeastern Cooperative Wildlife Disease Study from December 2018 to October 2021. No. Positive/No. Samples ( % ) Virus Spleen Liver Bone Marrow P a LPDV 30/58 (51.7) c 20/58 (34.5) b 38/58 (65.5) d , 0.001 REV 20/58 (34.5) bc 16/58 (27.6) b 24/58 (41.4) c 0.008 a Wald test P -value. b,c,d Within rows, percentages with a superscript in common do not differ with a level of significance of 5 % over all comparisons. 146 JOURNAL OF WILDLIFE DISEASES, VOL. 60, NO. 1, JANUARY 2024 Downloaded from https://jwd.kglmeridian.com at 2026-05-01 via free access ( Anas platyrhynchos ) in China (Jiang et al. 2014; Ferro et al. 2017; Liu et al. 2019; Caleiro et al. 2020; Liu et al. 2020; Li et al. 2021; Shi et al. 2021; Su et al. 2021). In con- trast, turkeys (domestic and wild) are the only avian species known to be susceptible to natural LPDV infections (Biggs et al. 1978; MacDonald et al. 2019b). Recently docu- mented REV detections have elevated global interest in determining REV prevalence and potential health impacts on a variety of bird species (Caleiro et al. 2020; Li et al. 2021; Shi et al. 2021). Transmission mechanisms of REV have been well delineated in domestic F IGURE 3. Examples of characteristic gross and microscopic lesions of lymphoproliferative disease associ- ated with LPDV and REV, which are grossly and histopathologically indistinguishable, in Wild Turkeys ( Melea- gris gallopavo ). A. Markedly thickened and discolored (tan to yellow) skin over the head and neck corresponding to lymphoma in an adult female Wild Turkey hen from which both REV and LPDV were detected. B. Markedly thickened skin and soft tissues over the intertarsal joint (arrows) of the same Wild Tur- key in image A. C. Neoplastic lymphocytes (lymphoma) in the renal interstitium (arrows) of a male, juvenile (poult) Wild Turkey with only REV detected (LPDV not detected); renal tubules are markedly dilated and con- tain secretory product (arrowheads). D. Marked expansion of the dermis of the skin over the leg by neoplastic lymphocytes (lymphoma; arrows) in an adult male Wild Turkey from which only LPDV was detected (i.e., REV not detected). E. Neoplastic lymphocytes (lymphoma; arrows) that invade the myocardium of an adult male Wild Turkey from which only REV was detected (i.e., LPDV not detected). F. Widespread neoplastic lymphocytes in the hepatic parenchyma (arrows) of the same Wild Turkey in image E. ADCOCK ET AL.—RETROVIRUS DETECTION AND DISEASE IN WILD TURKEYS 147 Downloaded from https://jwd.kglmeridian.com at 2026-05-01 via free access fowl but remain poorly understood in wild birds. Transmission occurs both horizontally (bird to bird) and vertically (maternally or via copulation; Witter and Salter 1989; Su et al. 2021). The transmission modes remain unknown for LPDV. Tissue collection protocols should be tai- lored to targeted pathogens based on surveil- lance or research goals, while considering the distinction between viral detection and virus- associated disease. Based on previous studies in Wild Turkeys, spleen, liver, and bone mar- row are deemed diagnostically useful for LPDV detection, raising the question of whether these tissues also are useful for REV detection (Allison et al. 2014; Thomas et al. 2015; Niedringhaus et al. 2019). Our compari- son of LPDV and REV detection in these tis- sues reveals that bone marrow, although not producing a 100 % detection rate, is a better target tissue for diagnostic testing for both LPDV (65.5 % detection rate) and REV (41.4 % detection rate) compared with spleen and liver. This result differs from previous research that found no significant difference in LPDV detec- tion between liver, spleen, and bone marrow in Wild Turkeys submitted for diagnostic eval- uation, although their sample number was smaller than in our study ( n ¼ 20 vs. 58, respec- tively; Thomas et al. 2015). Skin is an important organ for health assessments in Wild Turkeys, as it is highly visible to hunters and biologists, and abnor- malities in the skin often are the impetus for submitting Wild Turkeys for diagnostic evalu- ation. In our study, skin had occasional LPDV and REV detections, and grossly and micro- scopically evident proliferative skin lesions were attributed to LPDV (i.e., LPDV-only– infected turkeys), but also occurred in turkeys with LPDV and REV coinfection. However, skin was not routinely evaluated via histopa- thology unless gross lesions were observed, and no gross skin lesions were observed in any REV-only–infected turkeys. Infections with LPDV and REV are suspected to cause immunosuppression in Wild Turkeys, which may have indirect health effects, including predisposing to secondary or exacerbating concurrent infections, such as with avian poxvi- rus (Alger et al. 2015; Thiemann et al. 2022). In approximately 28 % of the birds infected with LPDV, REV or both in our study, pox was also detected, often manifesting as grossly nodular skin disease of the head and neck. Similarly, in Mississippi, some Wild Turkeys that had LPDV and REV coinfection ( n ¼ 8), LPDV only ( n ¼ 8) and REV only ( n ¼ 2) also had pox (Thiemann et al. 2022). In general, Wild Turkeys with LPDV and/or REV were in poor overall health, as indicated by poor nutritional condition, mul- tiple pathogen infections, or both. Demographic and seasonal data analysis among Wild Turkeys infected with LPDV, REV, or both is important because of their potential impacts on disease dynamics. Univari- ate analysis for LPDV and REV in our study revealed season as the only variable that was sig- nificantly associated with LPDV prevalence and not REV prevalence. Winter was most highly associated with LPDV prevalence, followed by summer. In a New York study, a lack of associa- tion between LPDV prevalence and study year was noted, consistent with our results (Alger et al. 2017). Although annual REV prevalence has not previously been assessed, in our study, REV univariable association prevalence was sig- nificantly associated with year, season, and sex. Multivariable analysis, however, revealed that REV prevalence was significantly associated with year and season, but not sex. After adjusting for annual variation, the odds of detecting REV were significantly higher in fall and winter com- pared with spring and summer. Seasonal influ- ences on REV infection prevalence may occur because of varied foraging strategy in colder months, or by facilitated transmission through bird congregation during food scarcity (Alger et al. 2017). In contrast to previous studies, we did not find that age or sex played a role in LPDV or REV infection status (Alger et al. 2017; MacDonald et al. 2019a; Niedringhaus et al. 2019). This may reflect biases towards visi- ble (e.g., adult) sick or dead turkeys (with 50 % females, 50 % males) compared with other stud- ies that had a higher female to male ratio and fewer adult turkeys tested (Alger et al. 2017; 148 JOURNAL OF WILDLIFE DISEASES, VOL. 60, NO. 1, JANUARY 2024 Downloaded from https://jwd.kglmeridian.com at 2026-05-01 via free access MacDonald et al. 2019a). Finally, our analysis did not reveal significant differences in LPDV and REV prevalence by geographic region. Importantly, paucity of knowledge on viral trans- mission routes for both viruses limits our ability to interpret annual, seasonal, regional, and demographic associations. Further, the variety and, in some cases, paucity of results across cur- rently published LPDV and REV studies per- taining to associations among these factors and LPDV and REV infection prevalence in Wild Turkeys warrant longer-term studies that repre- sent diverse demographic groups and expanded geographic regions to elucidate these poorly understood host-pathogen systems. With recent Wild Turkey population declines across much of its range, disease concerns abound based on a variety of circulating pathogens, among which LPDV and REV should be at the forefront of further investigations (Niedringhaus et al. 2019). More information about tissue tropism of these viruses is needed, along with development of advanced diagnostic modalities to distinguish the two viruses microscopically within lesions (e.g., immunohistochemistry, in situ hybridization). Additional surveillance, continued diagnostic evaluation, and controlled infection studies in Wild Turkeys would help answer these and other questions to advance our understanding of their pathogenesis and potential environmental associations, and ultimately to consider potential population-level health impacts of these viruses on Wild Turkeys. ACKNOWLEDGMENTS We thank Charbel Gerges and Sydney Burke (Southeastern Cooperative Wildlife Disease Study [SCWDS], University of Georgia) for their assis- tance with sample processing. We also thank SCWDS diagnostic service members for sample collections and valuable contributions to diagnos- tic case results, as well as University of Georgia Histopathology Laboratory staff for processing tis- sues for histopathology. We thank member state wildlife management agencies of SCWDS for sup- port provided by the Federal Aid to Wildlife Res- toration Act (50 Stat. 917), and the United States Fish and Wildlife Service and the United States Geological Survey Ecosystems Mission Area for their continued support. SUPPLEMENTARY MATERIAL Supplementary material for this article is online at http://dx.doi.org/10.7589/JWD-D-23-00012. LITERATURE CITED Alger K, Bunting E, Schuler K, Jagne J, Whipps CM. 2015. Diagnosing lymphoproliferative disease virus in live wild turkeys ( Meleagris gallopavo ) using whole blood. J Zoo Wildl Med 46:806–814. Alger K, Bunting E, Schuler K, Whipps CM. 2017. 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