Experimental studies on Marek's disease in Japanese quail (Coturnix coturnix japonica)

Day-old quails experimentally infected with Marek's disease (MD) virus of quail origin developed lymphoid tumors. The severity of the disease increased considerably with serial passage. Tumor transplants could be made with cells derived from gross tumors in skeletal muscles, spleen cells, and blood from MD-affected quails. After five to six serial transplants, the tumor could not be transplanted further. Marek's disease tumor-associated surface antigen (MATSA) was demonstrated in lymphoid cells of spleen and peripheral blood lymphocytes of MD-affected quails. The MATSA of quail differed from the MATSA of chicken. Chickens were susceptible to MD virus isolated and propagated in quails.     

Immunopathology of Marek's disease in quails: presence of antinuclear antibody and immune complex.

Antinuclear antibody (ANA), a marker for autoimmune reactions, was detected in the sera of quails with Marek's disease (MD). The autoantibody was detected 3 weeks after infection in quails infected with chicken Marek's disease virus and 4 weeks after infection in quails infected with quail Marek's disease virus. The ANA titers were low and ranged from 10 to 40. A speckled type of nuclear fluorescence was the characteristic staining feature. In addition to the presence of ANA, immune complexes (IC) were also detected in the kidney glomeruli of quail infected with Marek's disease virus. Initially about 25-30% of the glomeruli in the kidneys of infected quails had IC deposits. In subsequent periods, the amount of IC deposit and the number of glomeruli showing IC also increased considerably. The findings of the present study suggested autoimmunity may play a pathogenic role in MD.     

A TRANSMISSIBLE CHICKEN TUMOUR ASSOCIATED WITH RETICULOENDOTHELIOSIS VIRUS INFECTION

Histiocytic lymphosarcomas of the intestine, liver, spleen and sciatic nerve were found at necropsy in a 36-week-old laying hen that was culled from a flock of 1800 birds because of emaciation. Type C particles were observed in ultrathin sections of liver and spleen. The serum of the hen contained reticuloendotheliosis virus (REV) antigen, and antibody against REV, but lacked antibodies reactive with Marek's disease virus or subgroups A and B of Rous sarcoma virus. The tumour was transmitted to chickens using a suspension of the initial tumours. These experimental tumours were then transmitted to further chickens, using cultured spleen cells, viable spleen cells that had been stored frozen, and disrupted spleen cells. The tumours, which developed after incubation periods as short as 2 weeks, were histologically similar to those in the original hen. A few chickens also developed feather abnormalities. The chickens with experimentally transmitted tumours developed antibody against REV and REV antigen was demonstrated in cultured cells from these chickens. The chickens failed to develop antibody against Rous sarcoma virus and only 1 of 29 developed antibody against Marek's disease virus.     

A study of Marek's disease in Japanese quails vaccinated with herpesvirus of turkeys

In a study of outbreaks of Marek's disease in quails, 220 adult quails vaccinated with herpesvirus of turkeys (HVT) were examined pathologically and serologically for Marek's disease (MD). Forty-three of the 220 quails exhibited microscopic lesions similar to those of chickens with MD. MD-virus-specific antigen was found in feather tips of 44 of the 220 birds, and the HVT-specific antibody was found in sera of 56 of the 220 birds by agar gel precipitation. There was a positive correlation between the incidence of lymphomatous changes and the presence of MD-virus-specific antigen, and there was a negative correlation between the incidence of lymphomatous changes and the presence of antibody against HVT on a flock basis.     

Anatomical distribution of T- and B-lymphocytes in Marek's disease--an immunohistochemical study

Neural lesions of Marek's disease, Marek's disease tumours in the ovary, liver, and kidney, as well as spleen and bursa of Fabricii of chickens bearing Marek's disease tumorous infiltrations, were examined by a new immunohistochemical technique basing upon Sternbergers unlabelled antibody enzyme method which allows the exact localization of lymphoid cells based on their surface antigens. Type C neural lesions contained T-lymphocytes almost exclusively. Type B neural lesions had relatively high proportions of T- and B-lymphocytes, and severe type A neural lesions possessed one part of heavily labelled T-lymphocytes and a number of cells stained weakly by rabbit-anti-chicken-T-cell-globulin. Tumorous infiltrations had similar characteristics as type A neural lesions. Spleen and interfollicular spaces of bursa of Fabricius were infiltrated by T-lymphocytes.     

INFECTION STUDIES ON A RETICULOENDOTHELIOSIS VIRUS CONTAMINANT OF A COMMERCIAL MAREK''S DISEASE VACCINE

Reticuloendotheliosis virus (REV) was isolated in cell cultures from commercial Marek's disease (herpesvirus of turkeys) vaccine and re-isolated from the organs of vaccinated chickens. Runting and feathering abnormalities were produced when 1-day-old specific pathogen free chickens were inoculated with REV. Histopathological lesions in infected chickens were hypoplasia of the thymus, bursa and spleen, and inflammation of the proventriculus, kidneys and liver. Serological responses to REV were detected by the indirect immunoflorescence test in chickens directly inoculated with contaminated vaccine, and spread of REV infection to in-contact chickens was demonstrated by histopathological and serological investigations.     

In situ detection by monoclonal antibody D-35.1 of cells infected with Marek's disease virus that interact with splenic ellipsoid-associated reticulum cells

Immuno- and enzyme-histochemical staining procedures were used to investigate in vivo the interaction of Marek's disease virus (MDV) with splenic non-lymphoid cells. The newly developed monoclonal antibody D-35.1, which recognizes all three MDV serotypes, was used to study the localization of MDV at various times after intramuscular inoculation of 1-day-old chicks with MDV strain K. The D-35.1-positive cells were detected in the bursa of Fabricius, spleen, thymus, proventriculus, and cecal tonsils, and the number of chickens showing the cells increased between days 4 and 10. From day 21, the skin of the chickens contained D-35.1-positive feather follicles. The D-35.1 monoclonal antibody did not stain any cells in peripheral blood, nerves, kidney, and gonads at any time. In addition, D-35.1-positive cells were not detected in lymphoproliferative lesions in visceral organs and peripheral nerves. Double staining procedures on serial sections using monoclonal antibody CVI-ChNL-68.2, specific for splenic ellipsoid-associated reticulum cells, revealed that the majority of D-35.1-positive cells were situated in the peri-capillary sheath of reticulum cells at day 10. The sheath of cells detected by monoclonal antibody CVI-ChNL-68.2 was disrupted, and they were clustered around D-35.1-positive cells. These results support the hypothesis that ellipsoid-associated reticulum cells are involved in the early pathogenesis of Marek's disease.     

Experimental reproduction of enteritis in bobwhite quail (Colinus virginianus) with Cryptosporidium and reovirus

Five-day-old bobwhite quails were inoculated with reovirus and Cryptosporidium previously isolated from the intestinal contents of young, commercially raised bobwhite quails experiencing severe enteritis. Quails inoculated with reovirus alone did not develop clinically apparent disease, infection was localized principally in the intestinal tract, and no lesions were detected. Quails inoculated with Cryptosporidium, alone or with reovirus, developed severe enteritis with high mortality and marked growth depression. Cryptosporidia caused blunting of intestinal villi and provoked a mononuclear cell response in the lamina propria. The severity of intestinal lesions correlated with numbers of parasites. An apparent synergistic effect in dually infected quails was indicated by enhanced Cryptosporidium oocyst shedding, greater numbers of cryptosporidia in the intestinal tracts, and systemic reovirus infection. In addition, multifocal liver necrosis was detected in dually infected quails but was absent in quails infected with only reovirus or Cryptosporidium. The results suggest that Cryptosporidium promoted systemic spread of reovirus, and reovirus intensified Cryptosporidium infection, but no significant synergistic effect on mortality or weight gain was detected. The most important agent in the naturally occurring acute enteritis of bobwhite quails was Cryptosporidium.     

Immunological aspects of Marek's disease in chickens with maternal antibodies]

The dynamics of the production of immunoprecipitation antibodies to Marek's disease virus was studied in the serum of chickens with maternal antibodies in relation to the occurrence of the immunoprecipitation antigens of Marek's disease virus in feather follicles. One-day-old chickens were infected by the contact method with Marek's disease virus. The first occurrence of immunoprecipitation antigen was detected on the 14th day after infection and this occurrence persisted throughout the experiment, i. e. until the 112th day after infection. The antibodies were first detected the 28th day after infection and their titre kept rising until the 98th day after infection. Immunoprecipitation antibodies and antigens of Marek's disease virus were detected in some tumorously changed kidneys. Immunoelectrophoretic examination revealed in the same kidneys immunoglobulins of the class IgY, IgA and beta-globulin. The slowest-migrating fraction of IgY, together with IgA, beta-globulin and C-reactive protein were detected in the skin extracts from infected poultry. Indirect haemagglutination enabled the detection of the presence of haemagglutination antibodies in rabbit immunoglobulin to the skin antigen of Marek's disease virus, and in avian immunoglobulin to the same virus. Haemagglutination antigen was revealed in the extract from tumorously changed kidneys.     

Distribution and function of non-lymphoid cells positive for monoclonal antibody CVI-ChNL-68.2 in healthy chickens and those infected with Marek's disease virus

Immuno-enzyme histochemistry was used to study the staining pattern and tissue distribution of monoclonal antibody CVI-ChNL-68.2 that specifically reacts with a subset of non-lymphoid cells in healthy chickens and those infected with Marek's disease virus (MDV). Functional characteristics of CVI-ChNL-68.2-positive cells, e.g. antigen uptake, are determined. In the liver CVI-ChNL-68.2 recognizes reticulum cells, whereas in the bursa of Fabricius it detects single cells in the interfollicular connective tissue. In the spleen CVI-ChNL-68.2 reacts selectively with the reticulum cells of the ellipsoid. In some MDV-infected chickens the splenic reticulum cells show a different staining and distribution pattern. Furthermore, the proliferative lesions associated with Marek's disease contain many CVI-ChNL-68.2-positive cells. The possible role of CVI-ChNL-68.2-positive cells in disseminating Marek's disease virus is discussed.     

An Outbreak of Marek's Disease in Chickens in Central Ethiopia

A study was conducted on an outbreak of Marek's disease in a commercial poultry farm containing 8500 chickens in central Ethiopia. On repeated visits, farm and flock history was collected, sick birds were examined and clinical signs and daily mortality were recorded. A total of 80 (27 sick and 53 dead) birds 12-22 weeks old, were collected, autopsied and examined. The mortality rate was 46% for the first 14 weeks of the outbreak. Acute and chronic (classical) forms of the disease, the respective occurrence of which varied significantly (p<0.01) in young (14.6% vs 85.4%) and adults (48.7% vs 51.31%) were manifested. All the autopsied birds had gross and microscopic lesions indicative of Marek's disease in the peripheral nerve(s) and/or visceral organs. Lesions involving peripheral nerves and visceral lymphomas were recorded mainly in adults (28/35, 80%) and young birds (34/45, 75%), respectively. These differences in the two age groups were statistically significant (p<0.01). Young birds seem to be highly susceptible to the acute disease. Poor management, overstocking and lack of vaccination might have favoured the outbreak. Marek's disease causes considerable economic loss and is a major threat to poultry production in Ethiopia. This report emphasizes that Marek's disease should be considered as a disease of economic significance in chicken production in Ethiopia and warrants due attention.     

Infectious bursal disease virus infection in the quail-chicken hybrid

Hybrids produced from crossing Cornell K-strain white leghorn chickens and Line II Japanese quails were studied for susceptibility to infection with infectious bursal disease virus (IBDV). Quail-chicken hybrids were infected successfully following inoculation with IBDV at 14, 21, or 52 days of age. In most cases, precipitating antibodies were detected in serum by 10 days postinoculation (PI). Although no clinical signs or gross lesions were evident in the bursa of Fabricius of hybrids, histologic changes in the bursa were detected upon microscopic examination using hematoxylin and eosin staining. Chickens were successfully infected also; they had gross and microscopic lesions in the bursa and produced precipitating antibodies. In addition, staining of bursal sections with low concentrations of peroxidase-conjugated concanavalin A revealed a rearrangement of a leukocyte cell type (probably macrophages) in infected chickens and hybrids. Japanese quails were refractory to infection; they showed no bursal changes and did not form precipitating antibodies.     

Pathologic changes in the organs in chickens after infection with the turkey herpesvirus THV-BIO-I]

The objective of our work was to investigate the dynamics of pathological lesions of chicken organs after infection with high doses of turkey herpesvirus THV-BIO-I. This virus strain is commonly used in form of the Marvak vaccine against Marek's disease of poultry in Czechoslovakia. High doses of the vaccine are used in practice with respect to the epizootological situation. The incidence of pathological lesions in the organs of Brown Leghorn chickens was investigated in a five-week experiment. One-day chickens were infected intramuscularly with the HVT strain at the doses of approximately 10(2), 10(3) and 10(4) PFU in 0.2 ml of infective inoculum per chick. The body weights of ten chickens of each group were recorded at intervals of 1, 2, 3 and 5 weeks after infection, serological examination was performed for precipitating antibodies to MDV and the feather was examined for MDV-antigen. Bursae Fabricii and spleens were weighed. Thymus, bursae Fabricii, spleens, peripheral nerves (n. ischiadicus and pl. brachialis) and gonads were sampled for histopathological examination. Neither maternal nor post-infection antibodies were found in any chick. Cytolytic lesion severity of lymphoid organs was scored using the scale of immunosuppression degrees (0-4). Morphological criteria were published in a previous paper (Halouzka and Jurajda, 1991b). The differences observed in the weights of bursa Fabricii and spleen between the infected and control chickens were not statistically significant. The observed lymphoid infiltrations in the skin, gonads, nerves and other tissues following the HVT infection are well-known and correlate with the infection dose.(ABSTRACT TRUNCATED AT 250 WORDS)     

The early pathogenesis in chicken inoculated with non-pathogenic serotype 2 Marek's disease virus.

A newly cloned serotype 2 Marek's disease virus (MDV), strain ML-6, was inoculated via the nasal cavity in specific-pathogen-free chicks to examine early virus replication and the expression of Marek's disease (MD)-related antigens. Following inoculation, viral intracellular antigens (VIAs) were detected in lymphoid organs (bursas and spleens) between 5 and 14 days post inoculation (PI), in feather follicles between 14 and 30 days PI, and in lungs at 3 days PI by the immunohistopathological staining of avidin-biotin-peroxidase complex method. But, very few VIAs were expressed in the thymuses between 5 and 14 days PI. However, MD tumor-associated surface antigens were not detected in any organs. Viruses were isolated from separated spleen cells at 14 and 30 days PI. Fluorescent antibodies of convalescent sera were also detected after 10 days PI. As most of the VIAs were detectable in B-cells in bursas and spleens. B-cells were considered to be the main first target cells for the serotype 2 MDV infection.     

Comparative pathogenesis studies with oncogenic and nononcogenic Marek's disease viruses and turkey herpesvirus.

An apparently nononcogenic Marek's disease virus (SB-1) and turkey herpesvirus could be readily isolated from spleen, bursa of Fabricius, thymus, and peripheral blood lymphocytes of chickens beginning 4 to 6 days after inoculation, but unlike infections with two isolates of oncogenic Marek's disease virus (JM-10 and CU-2), virus replication in these cells was rare, and necrosis in the organs was essentially absent. Splenic enlargement was observed regularly during the first 4 to 11 days after inoculation, and Marek's disease tumor-associated surface antigen was observed on splenic and other lymphocytes in the four viral inoculation groups. Cellular cytotoxicity of splenic lymphocytes was demonstrated in vitro with cultured Marek's disease tumor cells (MSB-1 lymphoblastoid cell line) as the target in a chromium-release assay. The four viral infections induced sensitized lymphocytes.     

Effects of IgY antibody on the development of Marek's disease.

The effects of passive immunization with immunoglobulin Y (IgY) on the pathogenesis of Marek's disease (MD) were examined in an experimental line of White Leghorn chickens highly susceptible to MD. Purified IgY with anti-MDV antibody activity, when injected into chicks, delayed the development of MDV viremia and lesions until 9 days postinoculation (PI) with Marek's disease virus (MDV). The blastogenic response of spleen cells to concanavallin-A was depressed at 6 days PI in the birds without passive immunization, whereas it was not totally depressed until 17 days in birds passively immunized with IgY anti-MDV antibody.     

雏鸡马立克氏病强毒感染后脂质过氧化物的含量变化

１日龄雏鸡马立克氏病强毒（ｖＭＤＶ）人工感染马立克氏病（ＭＤ）发病率６２％,ＭＤ死亡率３４％;脾脏、胸腺、法氏囊、心脏、肝脏、肾脏、性腺脂质氧化物（ＬＰＯ）含量高于（Ｐ＞０．０５）或显著高于健康对照雏鸡（Ｐ＜０．０５）。     

Cyclophosphamide-induced amelioration of Marek's disease in Marek's disease-susceptible chickens.

Bursa- and thymus-dependent functions were examined in Marek's disease (MD)-susceptible normal chickens and in chickens treated with 5 and 16 mg of cyclophosphamide (CY) at the time of hatching. Chickens not exposed to Marek's disease virus (MDV) and treated with CY temporarily lost mitogenic response to concanavalin A but regained full response after 5 weeks. Bursa-dependent functions, such as presence of germinal centers in spleen and cecal tonsils, morphologic features of bursa, and sheep red blood cell antibody response were completely lost in chickens treated with 16 mg of CY and only partly retained in chickens treated with 5 mg of CY. In chickens exposed to MDV, the degree of thymus-dependent spleen cell mitogenic response was directly related to frequency and severity of MD. Chickens treated with 16 mg of CY had a mild mitogenic depression and low frequency and severity of MD lesions, whereas those treated with 5 mg of CY and those not treated had marked mitogenic depression and high frequency and severity of MD. Suppressions of bursa- and thymus-dependent functions by MDV alone were also evident when comparing MDV-exposed and nonexposed chickens. The results also indicate that presence of small, residual amounts of humoral factor(s) may enhance MDV oncogenesis.     

Violet mink develop an acute disease after experimental infection with Aleutian disease virus (ADV) isolate ADV SL3

Six-Aleutian (aa)-genotype violet mink were infected intraperitoneally with the Aleutian Disease Virus (ADV) bone marrow derived isolate ADV SL3. All animals developed virus-specific antibodies and hypergammaglobulinaemia. Mortality during the fourteen week duration of the infection was 50%. The virus induced (histo)pathological lesions typical for Aleutian Disease. By immunohistochemical examination using a virus capsid-specific monoclonal antibody viral antigen was detected in lymph nodes, spleen, kidneys and once in hepatic Kupffer cells. By Southern blot and in situ hybridization studies with strand-specific RNA probes able to distinguish viral replicative forms from merely sequestered genomic DNA, ADV replication was detected in mesenteric lymph nodes and spleen. In one mink DNA replicative forms were also found in bone marrow cells or mononuclear cells of the peripheral blood, respectively. Only single-stranded viral DNA was detected in liver, kidney, gut and lung of infected animals. From Southern blot hybridization results a different, possibly organ-specific permissiveness of ADV in vivo is suggested.