• Journal of the korean veterinary medical association
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• v.25 no.5
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• pp.282-291
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• 1989

Incidence of infectious bronchitis virus(IBV) infection in vaccinated breeder chickens was investigated by hemagglutination inhibition(HI)test for IBV using Mass 41 antigen. In the breeder chickens with the reduced egg production. chalky deposit. wrinkled

• Korean Journal of Poultry Science
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• v.19 no.1
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• pp.13-16
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• 1992

Avian infectious bronchitis virus(IBV) was propagated in SPF eggs and purified by sucrose density gradient centrifugation in order to prepare the antigen. Several fusions were made between mouse myeloma cells and spleen cells from BALB/c mouse immunized with IBV antigen and two hybridoma clones producing specific monoclonal antibody(MCA) against the IBV were established. The MCAs were classified as IgG type and revealed no neutralizing and hemagglutination inhibition activity. Using the MCA IBV antigen was detected by IFA method in tracheal smears made from chickens infected with IBV during the experimental period of 10 days.

• Korean Journal of Veterinary Service
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• v.14 no.1
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• pp.27-40
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• 1991

In order to investigate the biological properties, pathogenicity and immune responses in artficially infected SPF chickens with Avian infectious bronchitis virus that was isolated from chickens showing IB like signs in southern region of Chung buk. Results obtained throuth the experiments are summarized as follows. 1. From 15 IB suspected cases, two strains of IB virus were isolated, one each from the tracheas and lungs. 2. Infectious bronchitis specific embryo lesions were observed after four serial passages of the isolates in chicken embryos. 3. The field isolates and M-41 strain of IB virus interfered with the replication of Newcastle disease virus in chicken embryos. 4. When specific pathogen free chickens, two week old, were inoculated with the IB virus isolates, clinical respiratory signs as dyspnea, coughing were observed. Airsacculitis was observed by necropsy. 5. AGP antibody positive rates of inoculated SPF chickens were highest on day 14 and lowest on day 36, while HI antibody responses were detected on day 14 in all Groups, the reinoculated Group was shown highest titers. 6. By Indirect immunofluorescence antibody assay of artificially infected SPF chickens, the viral antigens were detected in tissues of larynx, trachea and lung on the 4 th to 7 th days post inoculation.

• Korean Journal of Poultry Science
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• v.35 no.1
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• pp.85-99
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• 2008

Avian reovirus (ARV) is a causative agent of viral arthritis/tenosynovitis, and malabsorption syndrome in broiler. The characteristics of malabsorption syndrome caused by ARV are diarrhea, poor feed conversion and stunting. Therefore, ARV infection has been recognized as one of the most important disease in the poultry industry because of economical losses. However, few study of ARV infection in broiler industry has been conducted in Korea. To evaluate the presence of ARV infection in broiler farms, epidemiological survey such as serological test and virus isolation has been conducted. For the serological survey using ELISA method, we selected five broiler farms which were located at different area and had a history of growth retardation, lameness, diarrhea and poor feathering. From these farms serum samples were collected at 1 day, 14 days and market age. All these farms had no history of vaccination against ARV. In addition to serological survey, we tried to isolate ARV from birds of designated farms at market age and collected feces and tissue samples such as cecal tonsil, intestine and liver. We were identified ARV by RT-PCR and transmissible electron microscopy. The samples were inoculated into 9-day-old embryonated eggs via the chorioallantoic membrane to observe the pock formation. For the pathogenicity test of ARV isolates, we inoculated with the isolates to the right footpad of 3-week-old SPF chicks and observed clinical signs and pathological changes for 14 days after challenge. Most broilers sampled for serological survey have maternal antibodies which were widely distributed at 1 day and decreased by 14 days. However, at the market age several broiler farms showed fairly high antibody titer against ARV. This increase of antibody titer at market age means the possible infection of ARV during the grow-out period. Among total 15 samples for the isolation of ARV. 2 samples were positive by RT-PCR and finally identified as a ARV. We inoculated these isolates in the SPF birds and observed that the antibody titer was increased from 7 days after challenge. However, we did not find any clinical signs both control and challenge groups. Based on the above results, it is clear that the ARV infection has been circulated in the broiler industry and caused significant economic losses. Further study is needed to evaluate the virulence of the isolates in the digestive system of broiler and the molecular characteristics of isolates.

• Parasites, Hosts and Diseases
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• v.29 no.4
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• pp.315-324
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• 1991

Each of SPF chicken(Hi-Line strain, 2-day-old males) was inoculated with 2.5 or $5\times10^4$ oocysts by stomach tube. The oocyst was the medium type of Cryptosporidium previously isolated from Korean chicken origin, and passed in 2-day-old SPF chicken. The patterns of oocyst discharge were monitored daily, and in order to observe the ultrastructure of the developmental stages, the bursa of Fabricius of the chicken was examined by transmission electron microscopy (TEM) on the 12th day postinoculation. The prepatent period for 8 chicken was 5.9 days postinoculation on the average, and the patent period was 12.9 days. The number of oocysts discharged per day for the chicken was reached peak on day 12 postinoculation on the average. A large number of oocysts was found in fecal samples obtained from inoculated chicken on days 8~14 postinoculation. The ultrastructural feature of almost every developmental stage of the medium type from chicken was very similar to that of Cryptosporidium previously isolated from mammalia including human and birds except for the attachment site of C. tsuris to the mucus cell from mammalia, but dimension of the oocysts from fecal samples of the medium type was different from those of C. meleagridis and mammalia origin. The above results reveal that the medium type of Cryptosporidium of Korean chicken origin is identified as Cryptosporidium baileyi.

• Korean Journal of Poultry Science
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• v.18 no.3
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• pp.141-150
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• 1991

A local isolate of chicken anemia agent (CAA), isolate 89-69. was tested for pathogenicity for chickens. When chickens from a specific pathogen free (SPF) flock were inoculated intramuscularly with the isolate at one day old, all the chickens showed severe anemia at 14 to 18 days post inoculation(DPI) and returned to normal at 25DPI, Some of the inoculated chickens (27∼33％) died between 13 to 17 DPI's with lesions of severe aplasia of bone marrow and thymic atrophy. In chickens kept in contact with inoculated chickens, some of the chickens had anemia at 25 and 28 DPI's. Virus could be reisolated from inoculated as well as in contact chickens till 21 DPI. Antibodies to CAA could be detected in all inoculated and in contact chickens when tested at 42 DPI by the indirect fluorescent antibody method. When chickens from a different SPF flock were inoculated at one day old, degrees of anemia, both in frequency of incidence and severity, were low These chickens were proved partly to have antibodies to CAA when tested for hatchmates. In a survey for antibodies to CAA in field chicken flocks, one out of 7 flocks(14％) aged 3 to 10weeks was antibody positive whereas 19 out of 20 flocks(95％) over 20 weeks of age were positive. Altogether 29 out of 39 flocks (74％) were antibody positive.

• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.255-258
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• 1996

Eight 2-day-old SPF Chickens were each inoculated Orally With 3 Sing1e dose Of 5 × 105 oocysts of Cryptosporinium boilevi. and immunoglobulin G (IgG) antibody responses were chronologically measured by indirect immunofluorescent antibody (IFA) assay. Anti-C. bcileyi IgG antibody levels remained high (1 : 106.67 to 1:512.00) for at least 4 months with 330 days of a detectable period. Ten days after the negative conversion, each chicken was re-challenged with 1 × 107 oocysts of the same species. Subsequent infection in 340-day-old individuals caused sudden elevated IgG antibody levels and the titer peaked on day 28 postchallenge inoculation (PCI), at 1:1.024 with a 65 days of detection period. Chickens in primary infection showed oocyst shedding profiles. but did not exhibit any oocyst shedding before or after experimental reinfection.

• Korean Journal of Veterinary Research
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• v.31 no.1
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• pp.55-61
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• 1991

The correlation between in vitro Congo-red binding properties of E coli and in vivo invasiveness of the organisms in SPF chickens and mice was investigated. Congo-red positive E coli colonies were dark-red color with a typical colonial morphology of rough appearance when grown on Congo-red medium, while Congo-red negative colonies showed pale-pink color and smooth surfaced colonial morphology. Pathogenicity of 10 Congo-red positive E coli for mice was observed in 92.5% but that of 5 Congo-red negative E coli was 45%. Invasiveness of 10 Congo-red positive E coli for chickens was observed in 96% of the SPF chickens tested but that of 5 Congo-red negative E coli was 16% only. These results of pathogenicity studies with E coli isolates indicate a significant correlation between Congo-red binding ability and virulence in avian Escherichia coli.

• Korean Journal of Veterinary Service
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• v.34 no.2
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• pp.139-148
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• 2011

Avian reovirus (ARV) and fowl adenovirus (FAdV) were evaluated for pathogenicity in specific pathogen free (SPF) chickens. ARV was isolated from the broilers with history of malabsorption syndrome (MAS). FAdV was isolated from the layer breeders with inclusion body hepatitis and hydropericardium syndrome. Total 6 inoculated groups including 1 un-inoculated group were organized and inoculated with the ARV and/or FAdV by oral route. The minimal pathological lesions and lower viral gene detection rates were present in the ARV inoculated groups compared to those of FAdV or ARV/FAdV inoculated groups. Common gross lesions in the ARV inoculated group were distended intestine with foamy contents and in the FAdV group there were foamy cecal contents and hydropericardium among the evaluation methods such as gross and histological lesion, viral gene detection, body weight and serum chemistry, histopathological lesion score was reliable especially in the liver lesions such as hepatic necrosis and lymphocytic infiltration. However, we did not success to evaluate the synergetic effect of mixed infection of ARV and FAdV in this study. Therefore, we need further study to reproduce malabsorption syndrome of ARV infection using different viral agent such as rotavirus and using different dose of virus.

• Korean Journal of Poultry Science
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• v.37 no.3
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• pp.255-263
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• 2010

Inclusion body hepatitis-hydropericardium syndrome (IBH-HPS) is an acute viral disease usually found in broilers aged from 3 to 5 weeks and causes up to 75% mortality. Among the 12 serotypes of fowl adenovirus group 1, serotype-4 (FAdV-4) was identified as a primary agent of IBH-HPS and was usually isolated in IBH-HPS cases in Korea since 2007. To prevent these IBH-HPS outbreaks in Korea, we developed the FAdV-4 inactivated vaccine using Korean isolate (ADL070244) and evaluated the efficacy of this vaccine. For the efficacy test, 2-week-old specific-pathogen-free (SPF) chickens intramuscularly inoculated with 1 or 2 dose of inactivated vaccine were used and challenged with FAdV-4 through either intramuscular or oral route at 2 weeks after vaccination. The vaccine induced good seroconversion which was confirmed by agar gel precipitation (AGP) test. In addition, the vaccine could decrease the FAdV-4 detection rate and histological lesion severity such as lymphocyte infiltration and necrosis in the liver comparing with those of non-vaccination group. Based on the current results, the developed FAdV-4 inactivated vaccine in this study was effective in the terms of reduction of virus detection rate and histological lesions severity. However, it was difficult to confirm the efficacy of the vaccine clearly because of no mortality and clinical signs in the non-vaccinated group after challenge. Therefore, we need further study to develop a standard challenged model system which could clearly evaluate the efficacy of the vaccines for FAdV-4.