A RETROSPECTIVE STUDY OF CAUSES OF SKIN LESIONS IN WILD TURKEYS (MELEAGRIS GALLOPAVO) IN THE EASTERN USA, 1975-2013

Experimental infection of domestic turkeys with lymphoproliferative disease virus of North American origin

Lymphoproliferative disease virus (LPDV) was first documented in wild turkeys in North America in 2009. LPDV infection is often subclinical but can manifest as lymphoid proliferation or round cell neoplasia. Despite high prevalence across many sampled areas corresponding to declining populations of wild turkeys, knowledge regarding LPDV pathogenesis, risk factors for disease development, and associated impacts on population dynamics are unknown. To understand transmission, viral shedding, and tissue tropism, we inoculated 21 domestic turkeys via the oral cavity, crop, nasal cavity, subcutis, or coelomic cavity. For 12 weeks, oropharyngeal swabs, cloacal swabs, and whole blood were collected weekly. At 1 week postinoculation, 3 turkeys (3/21; 14%) had detectable LPDV proviral DNA in blood by polymerase chain reaction, and 10 developed DNAemia (50%; 10/20) by 12 weeks. LPDV proviral DNA was intermittently detected in oropharyngeal and cloacal swabs. Splenomegaly was the most consistent gross finding in DNAemic birds (8/11; 73%). Lymphoid hyperplasia in the spleen was the most significant microscopic finding (9/11; 82%). Three turkeys (3/11; 27%) developed round cell neoplasia characterized by sheets of pleomorphic, round to polygonal cells in the adrenal gland, bone marrow, skin, small intestine, and/or spleen. LPDV was detected in the spleen and bone marrow from all turkeys with DNAemia and all neoplasms. Our study establishes that infection and disease with North American LPDV from wild turkeys can be experimentally reproduced in domestic turkeys, laying the groundwork for future investigations into LPDV pathogenesis, development of diagnostic techniques, and understanding the impacts of LPDV on wild turkey populations.

NOVEL AVIBACTERIUM SPECIES ASSOCIATED WITH SINUSITIS AND CONJUNCTIVITIS IN A MERRIAM'S WILD TURKEY (MELEAGRIS GALLOPAVO MERRIAMI) FLOCK IN COLORADO, USA

A Merriam's Wild Turkey (Meleagris gallopavo merriami) with periocular swelling and periocular skin crusting in Pueblo County, Colorado, USA, was diagnosed with severe catarrhal and fibrinous sinusitis and conjunctivitis. A novel clade of Avibacterium was detected in the exudate from this bird. Although eight additional turkeys culled from the affected flock did not have clinical signs or gross lesions, histologically all had mild-to-moderate chronic sinusitis, and infraorbital cultures yielded the same novel clade of Avibacterium that was found in the symptomatic turkey. The presence of this Avibacterium species in the absence of significant disease in some birds suggested that other factors might have been involved in the development of severe sinusitis and conjunctivitis in the symptomatic Wild Turkey. Negative culture results from a distant flock of Wild Turkeys, acquired with similar methods to the affected flock, suggested that this novel species of Avibacterium was not widespread throughout Wild Turkeys in Colorado.

Characterization of Avian Pox in a Ruffed Grouse (Bonasa umbellus) from Pennsylvania

A free-ranging, adult male ruffed grouse (Bonasa umbellus) was harvested by a hunter during November 2019 in Forest County, PA. The bird was submitted for necropsy due to a skin mass on its left leg. Upon necropsy, two proliferative skin masses were grossly visible, one on the left leg and one on the cere. An additional mass was present on the oropharyngeal mucosa covering the hard palate. These masses were diagnosed as avian pox based on histopathologic and cytologic findings, including marked epithelial hypertrophy, hyperplasia, vacuolar degeneration with eosinophilic stippling, and intracytoplasmic inclusion bodies. An avipoxvirus was detected using PCR and was identified as fowlpox virus through sequencing of the 4b core gene segment. The avipoxvirus from this case showed genetic similarity to isolates from Eastern wild turkeys (Meleagris gallopavo silvestris).

Health status of free-ranging ring-necked pheasant chicks (Phasianus colchicus) in North-Western Germany

Being a typical ground-breeding bird of the agricultural landscape in Germany, the pheasant has experienced a strong and persistent population decline with a hitherto unexplained cause. Contributing factors to the ongoing negative trend, such as the effects of pesticides, diseases, predation, increase in traffic and reduced fallow periods, are currently being controversially discussed. In the present study, 62 free-ranging pheasant chicks were caught within a two-year period in three federal states of Germany; Lower Saxony, North Rhine-Westphalia and Schleswig-Holstein. The pheasant chicks were divided into three age groups to detect differences in their development and physical constitution. In addition, pathomorphological, parasitological, virological, bacteriological and toxicological investigations were performed. The younger chicks were emaciated, while the older chicks were of moderate to good nutritional status. However, the latter age group was limited to a maximum of three chicks per hen, while the youngest age class comprised up to ten chicks. The majority of chicks suffered from dermatitis of the periocular and caudal region of the head (57-94%) of unknown origin. In addition, intestinal enteritis (100%), pneumonia (26%), hepatitis (24%), perineuritis (6%), tracheitis (24%), muscle degeneration (1%) and myositis (1%) were found. In 78% of the cases, various Mycoplasma spp. were isolated. Mycoplasma gallisepticum (MG) was not detected using an MG-specific PCR. Parasitic infections included Philopteridae (55%), Coccidia (48%), Heterakis/Ascaridia spp. (8%) and Syngamus trachea (13%). A total of 8% of the chicks were Avian metapneumovirus (AMPV) positive using RT-PCR, 16% positive for infectious bronchitis virus (IBV) using RT-PCR, and 2% positive for haemorrhagic enteritis virus (HEV) using PCR. All samples tested for avian encephalomyelitis virus (AEV), infectious bursal disease virus (IBDV) or infectious laryngotracheitis virus (ILTV) were negative. The pool samples of the ten chicks were negative for all acid, alkaline-free and derivative substances, while two out of three samples tested were positive for the herbicide glyphosate. Pheasant chick deaths may often have been triggered by poor nutritional status, probably in association with inflammatory changes in various tissues and organs as well as bacterial and parasitic pathogens. Theses impacts may have played a major role in the decline in pheasant populations.

Diseases of wild birds in southern Rio Grande do Sul, Brazil

ABSTRACT: Necropsy protocols of the “Laboratório Regional de Diagnóstico” of “Faculdade de Veterinária” of the “Universidade Federal de Pelotas” were reviewed, ranging the period from 2000 to 2018. Three hundred eighty one necropsies, 25 refrigerated and/or formaline fixed organs, and seven biopsies were received, representing 413 samples. Most of these materials were sent by the “Núcleo de Reabilitação da Fauna Silvestre” of “Universidade Federal de Pelotas” (NURFS-CETAS-UFPel) and were from municipalities within the range area of LRD-UFPel influence. Of the 413 cases 55 (13.31%) corresponded to metabolic/nutritional diseases; 50 (12.10%) to trauma; 35 (8.47%) to bacterial diseases/toxi-infections; 30 (7.26%) to parasitic diseases; 28 (6.77%) to fungal diseases; four (0.97%) to viral diseases and 17 (4.11%) to other diseases. Cases where it was not possible to determine the etiology, were in severe autolysis or were inconclusive totaled 194 (46.97%). Metabolic/nutritional diseases and traumatic injuries were the main cause of death in wild birds’, being Passeriformes the most affected order.

Multicentric Round Cell Neoplasms and Their Viral Associations in Wild Turkeys (Meleagris gallopavo) in the Southeastern United States

Multiple oncogenic viruses, including lymphoproliferative disease virus (LPDV) and reticuloendotheliosis virus (REV), have been detected in wild turkeys (Meleagris gallopavo). The prevalence of infection with these viruses appears to be more common than overt disease; thus, data on the manifestation of associated disease in wild turkeys are scarce. Diagnostic records from wild turkeys submitted to the Southeastern Cooperative Wildlife Disease Study from 1980 to 2017 were reviewed to identify cases of neoplasia. Neoplasia was reported in 59 of 851 (6.9%) wild turkeys submitted. Of the cases of neoplasia tested by polymerase chain reaction, LPDV was detected in 34 of 58 (59%), REV in 10 of 39 (26%), both viruses in 3 of 39 (8%), and no retroviruses detected in 5 of 39 (13%) turkeys. The most common gross lesions observed among turkeys with neoplasms were emaciation (30/40; 75%); nodules in the skin (26/59; 44%), liver (17/59; 29%), or spleen (9/59; 15%); and splenomegaly (14/59; 24%). Microscopically, nodules were composed of pleomorphic round cells with large eccentric nuclei and prominent nucleoli resembling lymphocytes or lymphoblasts (57/59; 97%) except for 2 cases, one of myeloid cell origin and the other with primarily spindloid cells. This study indicates the need to characterize the pathogenesis and potential health threat posed by REV and LPDV to wild turkeys. Experimental infection studies and the development of additional diagnostic tests to confirm the role of retroviruses in lymphoproliferative disease are warranted.

Evaluation of Cytology for Diagnosing Avian Pox in Wild Turkeys ( Meleagris gallopavo)

Avian pox virus is a common cause of proliferative skin disease in wild turkeys ( Meleagris gallopavo); however, other etiologies may produce grossly indistinguishable lesions. Common methods for diagnosing avian pox include histopathology, virus isolation, and PCR. While these methods are sufficient in most cases, each has their limitations. Cytology is a cost-effective and rapid approach that may be useful when traditional diagnostics are not feasible. The objective of this study was to evaluate the performance of cytology relative to histopathology and PCR for avian pox diagnosis in wild turkeys. Fifty wild turkeys were submitted for necropsy due to nodular skin lesions on unfeathered skin of the head. Of these, five had similar skin lesions on the unfeathered legs and 26 had plaques on the mucosa of the oropharynx or esophagus. Representative skin, oropharyngeal, and esophageal lesions from all birds were examined with cytology and histopathology. Skin lesions on the head of each bird were also tested for avian pox virus via PCR. Histopathology and PCR were equally sensitive in diagnosing avian pox from skin lesions on the head. There were no significant differences between cytologic and histopathologic diagnosis of avian pox from skin lesions on the head (sensitivity = 97.4%, specificity = 100.0%), legs (sensitivity = 75.0%, specificity = 100.0%), or from lesions in the oropharynx and esophagus (sensitivity of 62.5%). Similarly, there were no significant differences between PCR and cytology for diagnosis of pox viral skin lesions of the head. Relative to PCR detection of avian pox virus, cytology had a sensitivity of 90.0% and a specificity of 90.0%. These results suggest that cytology is a useful tool for diagnosis of avian pox in wild turkeys.

Galliformes and Columbiformes

Galliformes and columbifomes are closely associated with humans and some species have been domesticated for well over 5000 years. Both orders remain diverse, ranging from the common domestic poultry species (e.g., chicken, turkey, and squabs) to the more exotic species found in the wild and in zoological collections. While many species have been benefited from human activities and have increased their ranges, others have declined in numbers and some have become threatened (e.g., Trinidad piping-guan and wood quail) or even extinct (e.g., dodo and passenger pigeon). Nondomestic galliformes and columbiformes are susceptible to many of the same diseases that occur in domestic species, yet predisposition may be different. Furthermore, disease prevalence depends on exposure and potential risk factors. Infectious diseases that tend to be more common under intensive commercial production may not pose as great a risk to exotic and free-living species.