• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.471-477
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• 1991

Attempts to isolate chicken anemia agent (CAA) were made by inoculating tissue homogenates into MDCC-MSBl or LSCC-1104B1 cell lines and passaging the cells serially. CAA was isolated from the liver and thymus of 11 weeks old layer chickens and from the liver of 10 weeks old broiler breeder chickens. The layer flock experienced approximately 45% mortality during 9 to 14 week of age from gangrenous dermatitis and lymphoid organs of affected chickens were severely atrophied. The broiler breeder flock experienced approximately 7% mortality during 7 to 9 weeks of age and affected birds showed lesions of colibacillosis, staphylococcal arthritis, and coccidiosis together with atrophied lymphoid organs. The isolated viruses were identified as CAA by the indirect fluorescent antibody test and virus neutralization test using CAA immune sera including one to Gifu-1 strain of CAA. The CAA isolate 89-69, when inoculated into susceptible 1 day old SPF chicks, induced anemia 14 to 16 days after inoculation. It did not induce any cytopathic effects in chicken embryo liver and chicken embryo fibroblast cell cultures. Infectivity of the isolate was not affected by the treatment of chloroform or heat ($70^{\circ}C$ for 15 minutes).

• Korean Journal of Veterinary Service
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• v.33 no.1
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• pp.7-12
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• 2010

There are several immunosuppressive viral diseases in chickens such as avian adenovirus (AAV), chicken anemia virus (CAV), infectious bursal disease (IBD) and Marek's disease (MD). In this study, we have investigated two broiler chicken farms suffered from high mortality in Jeonbuk in July to August 2009. Clinically high fever and growth retardation were observed in the diseased chicken. In necropsy, the hemorrhages in thigh leg and thymus, hemorrhages and enlargement of liver, kidney and proventriculus, and yellowish fluid in heart were seen. Histologically, necrotic foci and basophilic intranuclear inclusion bodies of hepatocytes, hemorrhages and infiltrated lymphocytes in kidney and proventriculus were observed. By using polymerase chain reaction (PCR), the genes of avian adenovirus, CAV and ND virus were detected in specimens. We suggested that these coinfection cases with high mortality were due to primarily infection of immunosuppressive diseases such as avian adenovirus, CAV, followed by secondary infection of Newcastle disease (ND) virus.

• Korean Journal of Veterinary Research
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• v.33 no.2
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• pp.227-234
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• 1993

A serological survey for antibody to chicken anemia agent(CAA) was carried out by virus neutralization test. Antibody to CAA was detected in broilers and layers at different age groups. The results obtained were summarized as follows ; 1. Of a total of 1,035 chicken sera from 1.16 flocks 617 samples of sera were detected as positive(59.6%) and 95 flocks of a total flocks as positive(81.9%). 2. Proportion of positive sera by age were 92.3 %(88.9~100%) at 1 to 2 weeks of age, 56.4%(16.7~77.8%) at 3 to 9 weeks of age, 85.0%(50.0~100%) at 10 to 14 weeks of age and all tested sera were positive at over the 15 weeks age. 3. In each broiler and layer chicken 63.6% and 68.4% chicks possessed positive sera respectively. 4. Neutralizing antibody titer in age group was various from 1:10 to 1:6,400 and mean titer was 1:400 to 1:800.

• Journal of Veterinary Science
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• v.23 no.5
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• pp.63.1-63.14
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• 2022

Background: Chicken anemia virus (CAV) causes chicken infectious anemia, which results in immunosuppression; the virus has spread widely in chicken flocks in China. Objectives: The aim of this study was to understand recent CAV genetic evolution in chicken flocks in Guangxi Province, southern China. Methods: In total, 350 liver samples were collected from eight commercial broiler chicken farms in Guangxi Province in southern China from 2018 to 2020. CAV was detected by conventional PCR, and twenty CAV complete genomes were amplified and used for the phylogenetic analysis and recombination analysis. Results: The overall CAV-positive rate was 17.1%. The genetic analysis revealed that 84 CAVs were distributed in groups A, B, C (subgroups C1-C3) and D. In total, 30 of 47 Chinese CAV sequences from 2005-2020 belong to subgroup C3, including 15 CAVs from this study. There were some specific mutation sites among the intergenotypes in the VP1 protein. The amino acids at position 394Q in the VP1 protein of 20 CAV strains were consistent with the characteristics of a highly pathogenic strain. GX1904B was a putative recombinant. Conclusions: Subgroup C3 was the dominant genotype in Guangxi Province from 2018-2020. The 20 CAV strains in this study might be virulent according to the amino acid residue analysis. These data help improve our understanding of the epidemiological trends of CAV in southern China.

• Korean Journal of Veterinary Service
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• v.34 no.2
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• pp.149-152
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• 2011

From January to November in 2010, a result of chicken infectious anemia virus (CIAV) antibodies ELISA test about 500 number in 25 broiler breeder farms and 500 number in a broiler chickens slaughterhouse from 25 farms in Iksan area, Jeonbuk. The result of 100% (25/25) positive rate in broiler breeder farms group and 98.6% (493/500) positive rate from each individual. In each week-age group, 98.8% of 18~20 weeks and 98.3% of 21~24 weeks showed positive without any significant differences. In slaughterhouse case, broilers from the farms showed 36.0% (9/25) positive rate and each individual showed 20.4% (102/500) positive rate.

• Korean Journal of Veterinary Service
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• v.33 no.1
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• pp.13-21
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• 2010

Chicken anemia virus (CAV) has been recognized as an immunosuppressive agent and plays role as an etiological agent of multifactorial diseases in chicken. In this study, we investigated distribution of CAV antibody by ELISA and the virus gene by PCR in poultry farms in Jeongeup, Jeonbuk province. In the test using ELISA kit, 41 (95.3%) of 43 flocks and 88.6% of the individual chickens were positive, respectively. By PCR, 90.9% of the broiler breeders and 75.0% of White-semi breeders were found positive, respectively. All hatchery was negative by PCR. Of the clinical cases from 49 poultry flocks, 87.5% of flocks and 54.7% for each samples were found positive by ELISA, respectively. By PCR test, 21 (42.9%) of 49 flocks were positive. Major clinical signs of the infected flocks were growth retardation, femoral subcutaneous bleeding, depression, limping, and continuing selection. The genetic analysis of separate N genes of CAV showed highly homologous each other. The nucleotide sequence of field isolates had homology ranged from 99.9% to 97.5% with Chinese strains, and 99.9% to 99.6% with Japanese strain. Phylogenetic analysis based on the N gene of CAV isolates showed the closely relation with Chinese strains. The results of this survey could be used as basic data for development of vaccine.

• Korean Journal of Veterinary Service
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• v.41 no.1
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• pp.21-27
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• 2018

Fowl adenovirus (FAdV) and chicken anemia virus (CAV) have gained much importance as an immunosuppressive and economically important emerging pathogen of poultry. This study was carried out to investigate the prevalence of FAdV and CAV infection in chickens. The groups were divided into Korean native chickens, broiler, layer hens and broiler breeder and set up groups according to age. As results, 12.5% of the native chicken, 2.5% of broiler and 6.7% of layer chicken were positive, respectively by PCR for FAdV. Serological test showed that 84.8%, 79.0%, 97.7% and 96.1% of chickens were positive for antibody to FAdV in native chickens, broiler, layer hens and broiler breeder. The prevalence of CAV infection were 20.0%, 7.5%, 16.7% and 10.0%, based on CAV gene detection by PCR. In serological test of CAV, 40.6%, 35.9%, 84.8% and 73.9% of chickens were positive in that groups.

• 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.

• Korean Journal of Veterinary Research
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• v.38 no.4
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• pp.811-817
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• 1998

Humoral and cellular immune responses are depressed in chickens infected with reticuloendotheliosis virus(REV). The extent of depression is influenced by the age of infection and strain of virus. This study was conducted for investigation of immunosuppressive effects of a Korean isolate of REV. Chickens infected with REV-HI, a Korean isolate, at 1 day old were severely suppressed in the vaccinal immunity against Newcastle disease, infectious bronchitis and infectious bursal disease. But these immunosuppressive effects were not observed in chickens infected with the virus at 2 weeks of age, or contact infected by growing in-contact with inoculated chickens from one day old. The clinical signs following infectious laryngotracheitis(ILT) vaccination in chickens infected with REV-HI at 1 day old were more severe than those of uninfected chickens, and some of REV-infected chickens(21.4%) were died after the vaccination. Mortality following virulent ILT virus infection was increased in REV-HI infected chickens. Effects of REV infection at one day old to susceptibilities to subsequent Chicken anemia agent (CAA) infection were also studied. Chickens were infected with REV-HI at 1 day old and subsequently inoculated CAA at 1, 7, 14 and 28 days old, respectively. Mortalities of the chickens infected with REV-HI and subsequent CAA infection were 100, 100, 40 and 0%, respectively, whereas 23, 8, 0 and 0% of chickens infected with only CAA were died, respectively. These above all results suggest that a Korean isolate of REV may be highly immunosuppressive.

• Korean Journal of Veterinary Service
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• v.30 no.3
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• pp.321-327
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• 2007

This is a case report on the occurrence of inclusion body hepatitis (IBH) and infectious bursal disease (IBD) among the broilers in a local farm located in Wanju, Jeollabukdo. Mostly IBH could be caused by adenovirus if the bird's immune system was first weakened by exposure to immunosupressive agents such as infectious bursal disease virus (IBDV) and chicken anemia virus (CIAV). However IBH primary occurred before IBD in this case. And recent work has demonstrated that virulent adenovirus alone can produce the disease.