Enzootic Reticuloendotheliosis in the Endangered Attwater's and Greater Prairie Chickens

Abstract

Reticuloendotheliosis (RE) in captive greater prairie chickens (GPC, Tympanuchus cupido pinnatus) and Attwater's prairie chickens (APC, Tympanuchus cupido attwateri) was first reported in 1998. RE is caused by avian reticuloendotheliosis virus (REV), an oncogenic and immunosuppressive retrovirus infecting multiple species of wild and domestic birds. During August 2004 through May 2006 a captive population of prairie chickens was affected simultaneously with a neoplastic condition and also avian pox, the latter being detected in 7.4% (2 of 27) of all birds submitted for histopathology. A survey for REV was conducted in order to examine its possible role in mortality observed primarily in juvenile and adult specimens of prairie chickens. The investigative procedures included postmortem examinations, histopathology, molecular detection, and virus isolation. In total, 57 Attwater's prairie chickens and two greater prairie chickens were included in the study. REV infection was diagnosed using virus isolation or polymerase chain reaction (PCR) or both in 59.5% (28 of 47) of blood samples and/or tumors from suspect birds. Lymphosarcomas were detected in the tissues of 37% (10 of 27) of the birds submitted for histopathology. Such lymphosarcomas suggestive of RE represented the most frequent morphologic diagnosis on histopathology among 27 separate submissions of naturally dead prairie chickens. Overall, REV was detected or RE diagnosed in 34 of 59 prairie chickens (57.62%). The average death age of all birds diagnosed with lymphosarcomas on histopathology was 2.2 yr, ranging from <1 to 4 yr. Although deaths associated with neoplasia occurred in males and females in equal proportions based on submissions, overall more males were diagnosed as REV infected or RE affected (16 males vs. 7 females, and 11 birds of undetermined gender). Reticuloendotheliosis virus was confirmed as a significant cause of mortality in captive prairie chickens.

Co-Infection with Marek’s Disease Virus and Reticuloendotheliosis Virus Increases Illness Severity and Reduces Marek’s Disease Vaccine Efficacy

“…REV has extensive avian hosts, including chickens, turkeys, ducks, mallards, geese, peafowl, pheasants, pigeons, Hungarian partridges, Chinese partridges, Attwater’s prairie chickens, and many other wild birds [32,33,34,35,36,37,38,39]. REV infection of susceptible hosts, such as chicks, usually causes atrophy of the thymus and bursa of Fabricius, impairing the development and immune system functions of infected hosts, resulting in the suppression of host immune responses to some avian vaccines [40,41,42].…”

Characterization of reticuloendotheliosis virus isolates obtained from broiler breeders, turkeys, and prairie chickens located in various geographical regions in the United States

“…However, using monoclonal antibodies (Cui et al, 1986(Cui et al, , 1988, REV isolates can be classed into three distinct subtypes, 1, 2 and 3 (Chen et al, 1987). REV infects chickens, Attwater prairie chickens, Greater prairie chickens, turkeys, ducks, geese, pheasants, quail, and probably many other avian species (Witter et al, 1970(Witter et al, , 1981Purchase et al, 1973;Dren et al, 1983Dren et al, , 1988Dren et al, , 1998Fadly et al, 1996a;Crespo et al, 2002;Chen et al, 2006;Zavala et al, 2006;Barbosa et al, 2007;Fadly et al, 2008b;Lin et al, 2009). Based on virus or antibody detection assays, REV infection has been shown to be common, if not ubiquitous, in most countries (Witter & Johnson, 1985;Bagust et al, 1993;Fadly et al, 2008b).…”

Detection of reticuloendotheliosis virus by immunohistochemistry andin situhybridization in experimentally infected Japanese quail embryos and archived formalin-fixed and paraffin-embedded tumours

“…Total RNA from the REV strain APC-566 was used for synthesis of the riboprobe. This REV strain is an isolate from APC, which is a genome very similar to all other published REV sequences (Zavala et al, 2006;Barbosa et al, 2007a,b). First-strand cDNA was synthesized using 2 mg RNA, an oligo-dT(18) primer, 0.25 mM dNTPs, and Superscript reverse transcriptase (Invitrogen, Carlsbad, California, USA), according to the manufacturer's instructions.…”

“…Additional non-defective REV strains have been isolated from geese, pheasants, peafowl, Japanese quail, Greater prairie chickens (Tympanuchus cupido pinnatus), and Attwater's prairie chickens (Tympanuchus cupido attwateri). Natural or experimentally induced reticuloendotheliosis, an oncogenic and immunosuppressive disease, has also been reported in a variety of wild birds (Ley et al, 1989;Hayes et al, 1992;Peterson et al, 2002;Witter & Fadly, 2003;Zavala et al, 2006;Barbosa et al 2007a,b).…”