Lymphoproliferative Disease Virus in Wild Turkeys (Meleagris gallopavo) from Manitoba and Quebec, Canada.

This study describes the first recognized clinical case of lymphoproliferative disease virus (LPDV) in Canada and extends the range of LPDV in Canada through its detection in Manitoba and Quebec. We assessed the prevalence of LPDV in eastern wild turkeys (Meleagris gallopavo silvestris) with the use of whole, clotted blood from live birds in Manitoba (n = 65) and tissue samples collected postmortem in Quebec (n = 4). We tested for LPDV proviral DNA through PCR amplification and sequencing of a portion of the gag (p31) gene. Samples were also tested for reticuloendotheliosis virus (REV) by PCR. Twenty-four birds (34.8%) were positive for LPDV, including all diagnostic cases. One bird (1.4%) from Quebec had gross and microscopic lesions consistent with LPDV. Two turkeys (2.9%) were REV positive, one (1.4%) of which was co-infected with LPDV. Phylogenetic analysis of LPDV strains from Quebec and Manitoba grouped with previously sequenced samples from Ontario and publicly available sequences from a North American lineage. This study contributes valuable information toward ongoing surveillance and monitoring of LPDV in North America.

Virus de la enfermedad linfoproliferativa en pavos silvestres (Meleagris gallopavo) de Manitoba y Quebec, en Canadá. Este estudio describe el primer caso clínico reconocido del virus de la enfermedad linfoproliferativa (LPDV) en Canadá y extiende el rango de detección de este virus a través de su detección en Manitoba y Quebec. Se evaluó la prevalencia del virus de la enfermedad linfoproliferativa en pavos silvestres (Meleagris gallopavo silvestris) de la parte oriental, mediante el uso de sangre coagulada de aves vivas en Manitoba (n = 65) y de muestras de tejidos recolectadas postmortem en Quebec (n = 4). Se analizó el ADN proviral del virus de la enfermedad linfoproliferativa del pavo a través de la amplificación por PCR y la secuenciación de una parte del gene gag (p31). Las muestras también se analizaron para detectar el virus de la reticuloendoteliosis (REV) mediante PCR. Veinticuatro aves (34.8%) resultaron positivas para la presencia del virus de la enfermedad linfoproliferativa, incluyendo todos los casos diagnósticos. Un ave (1.4%) de Quebec tenía lesiones macroscópicas y microscópicas compatibles con este virus. Dos pavos (2.9%) fueron positivos a la presencia del virus de la reticuloendoteliosis, uno (1.4%) de los cuales se co-infectó con el virus de la enfermedad linfoproliferativa. El análisis filogenético de cepas del virus de la enfermedad linfoproliferativa de Quebec y Manitoba agrupó a estos virus con muestras previamente secuenciadas de Ontario y secuencias disponibles públicamente de un linaje de América del Norte. Este estudio aporta información valiosa para la vigilancia y el monitoreo continuos del virus de la enfermedad linfoproliferativa en América del Norte.

DETECTION OF LYMPHOPROLIFERATIVE DISEASE VIRUS IN CANADA IN A SURVEY FOR VIRUSES IN ONTARIO WILD TURKEYS ( MELEAGRIS GALLOPAVO).

The successful reintroduction of Wild Turkeys ( Meleagris gallopavo) to Ontario, Canada, has led to established populations in southern portions of the province and currently allows for biannual hunting seasons. These populations geographically overlap Domestic Turkey farms, an important sector of the provincial agri-food industry. Potential pathogen transmission between Wild Turkeys and Domestic Turkeys ( Meleagris gallopavo) is a concern, because they are susceptible to infection with many of the same pathogens and have direct and indirect contact in outdoor or open farm settings and contaminated environmental substrates. However, data concerning potential poultry pathogens in Wild Turkeys in Canada are scarce. Thus, we assessed the prevalence and geographic distribution of geographically relevant viruses in Ontario Wild Turkeys. Oropharyngeal and cloacal swabs were tested for avian influenza viruses (AIV) by real-time reverse transcriptase (RT)-PCR ( n=207), pooled tissues for lymphoproliferative disease virus (LPDV; n=183) and reticuloendotheliosis virus ( n=119) by PCR, and gross skin lesions by real-time RT-PCR for avian poxvirus ( n=8). We sequenced a fragment of the gag polyprotein (p31) gene of LPDV on a subset ( n=10) of LPDV-positive samples for phylogenetic analysis and tested additional upland game bird species ( n=39) and domestic fowl for LPDV ( n=17). To the best of our knowledge, we document the first detection of LPDV in Wild Turkeys in Canada, with a prevalence of 65% (119/183). Phylogenetic analysis revealed that LPDV sequences from Ontario were genetically similar to other North American strains and did not group into separate clades. Reticuloendotheliosis virus was detected in 4% (5/119) of LPDV-positive Wild Turkeys. Grossly evident skin lesions from five Wild Turkeys tested positive for poxvirus, and all turkeys tested negative for AIV. This study provides evidence of LPDV circulation in Canada and provides a baseline for comparison with future Wild Turkey pathogen surveillance and monitoring in Ontario and elsewhere.

Avian erythroblastosis virus isolated from chick erythroblastosis induced by lymphatic leukemia virus subgroup A.

A new strain of avian erythroblastosis virus (AEV), designated "AEV-H," was established by serial passages of a field isolate of avian lymphatic leukemia virus subgroup A [LLV(A)] in chicks from a White Leghorn flock of line 151 chicks. One stock of AEV-H contained 10(4) focus-forming units/ml virus and 10(9) tissue culture infective dose/ml LLV(A). All of the chicks that received ip inoculations of 0.2 ml AEV-H developed erythroblastosis complicated by fibrosarcoma 16-24 days (approximately equal to 17.7 days) after inoculation. Pathologic changes of erythroblastosis were macroscopically observed, mainly in such visceral organs as the liver, spleen, and bone marrow. In addition, microscopic changes were observed in the lung, kidney, ovary, and heart. Pathologic changes of fibrosarcoma were so conspicuous that they were recognizable by the naked eye in the pancreas and in the serous membrane of the intestine.

Low incidence of lymphoid tumors in chickens continuously producing endogenous virus.

A flock of 258 male and 243 female chickens of a cross of Regional Poultry Research Laboratory lines 15B and 7(2) were kept in a filtered-air positive-pressure house and observed for tumors from 100 to more than 729 days of age. These birds produced high titers of a subgroup E endogenous virus from the middle of the embryonic incubation period through the end of the experiment. No neoplasms were observed in the males. The females had two neoplasms indistinguishable from lymphoid leukosis and three other neoplasms not involving lymphoid cells. No evidence was found of infection with exogenous lymphoid leukosis viruses, Marek's disease virus, reticuloendotheliosis virus, or adenovirus (isolated on the isolation farm). Inoculation of another sample of this cross with a lymphoid leukosis virus of subgroup A resulted in 88% mortality with neoplasms (mostly lymphoid leukosis) by 167 days of age. The conclusion is that high levels of spontaneously produced endogenous virus do not induce high levels of neoplasms in chickens susceptible to lymphoid leukosis.

["Pharaoh" line culture of Japanese quail cells as a leukosis-free system for virus reproduction]. / Kul'tura kletok iaponskikh perepelov linii faraon kak bezleikoznaia sistema dlia reproduktsii virusov.

Contamination of Japanese quail, strain Pharaoh, cell culture with oncogenous and infectious avian viruses was studied. The susceptibility of the embryonal cell cultures of the Japanese quail, strain Pharaoh, to measles, parotitis and fixed rabies viruses was also determined. It was found that the sera of pubertal quails had no antibody to Rous sarcoma virus (RSV), strains Brian, RSV (RAV-1), Schmidt-Ruppin, Carr-Zilber, as well as to Marek's disease and Newcastle disease viruses. No reverse transcriptase activity was detected in the embryonal alantoic fluid of this avian species. The quails were less susceptible, as compared to the chicken, to Schmidt-Ruppin and Carr-Zilber strains of RSV. Measles, parotitis and fixed rabies viruses reproduced actively in the Japanese quail, Pharaoh strain, embryonal cell cultures. It is suggested that the embryonal cell cultures of this avian species can be used as a leukemia-free substrate for experimental studies and manufacturing of viral vaccines.

Avian oncogenesis induced by lymphoproliferative disease virus: a neglected or emerging retroviral pathogen?

Lymphoproliferative disease virus (LPDV) is an exogenous oncogenic retrovirus that induces lymphoid tumors in some galliform species of birds. Historically, outbreaks of LPDV have been reported from Europe and Israel. Although the virus has previously never been detected in North America, herein we describe the widespread distribution, genetic diversity, pathogenesis, and evolution of LPDV in the United States. Characterization of the provirus genome of the index LPDV case from North America demonstrated an 88% nucleotide identity to the Israeli prototype strain. Although phylogenetic analysis indicated that the majority of viruses fell into a single North American lineage, a small subset of viruses from South Carolina were most closely related to the Israeli prototype. These results suggest that LPDV was transferred between continents to initiate outbreaks of disease. However, the direction (New World to Old World or vice versa), mechanism, and time frame of the transcontinental spread currently remain unknown.

Normal and dystrophic embryonic chicken pectoralis muscle cultures: III. Viral infection of normal cell cultures.

Twelve-day normal and dystrophic chick embryo breast muscle cells were cultured for up to 14 days, using normal embryo extract in the culture medium. Fluorodeoxyuridine was added on day 3 to suppress fibroblast overgrowth. Three of 6 experiments with normal cells were severely infected with avian leucosis/sarcoma (ALS) virus particles. The findings appear to lend support to the suggestion that the ALS virus is a mitochondriophage. Infected cultures demonstrated a depressed rate of total protein synthesis as reflected by incorporation of [3H]leucine. Extractable protein and total protein content were also depressed within several days after ALS particles were identified. These findings reinforce caution in acceptance of the common assumption that viral infections are an unavoidable and metabolically benign component of muscle cell cultures.