5681
Ahmed Fotouh Abdallah Ibrahim
Pathological and Clinicopathological Diagnosis of
Avian Leucosis Type J
Avian leucosis virus type J, diagnosis, pathology, PCR
immunohistochemistry, hemogram, liver and kidney functions
This study was conducted to diagnose and study the pathogenesis of the avian leucosis virus type J (ALV-J) in naturally and experimentally infected chicken. It was conducted in two stages; field and experimental. In the field stage, 28 breeder and layer farms located in 3 governorates (El-Sharkiah, El-Dakahliah, and El-Kaliobiah) in Egypt were examined during 2017–2019. Clinical signs and mortality rate were recorded. Postmortem, Immunohistochemical, histopathological lesions, ALV-J antibody titer, molecular characterization and isolation of ALV- J were investigated in both meat-type and egg-type chickens. Clinical signs are mostly non-specific (weakness, dehydration and emaciation and may be abdominal enlargement). The mortality rates ranged from 0.6% to 1.8% per week. The ELISA test result reveals 122 positive samples for ALV-J (36.4%) which were (39%) in the breeder flocks and (33.5%) in the layer flocks. The PCR test showed 65 positive samples (69.9%). Gross lesions of liver, kidneys, spleen and heart were mostly greatly uniformly enlarged which occupied most of the abdominal cavity with diffuse grayish tumor infiltrates. Nonfunctional ovaries and poorly developedtestes were detected. Tumors of myelocytomatosis can be recognized on the surface of bones in association with the periosteum and cartilaginous areas. Microscopically, tumors consisted of masses of uniform, usually well-differentiated myelocytes or lymphoid cells or both. The myeloid cells when stained with Giemsa stain, granules appear brilliant red. The result of the immunohistochemical staining revealed that ALV-J positive signals were indicated by the brown staining, mainly presented in the spleen, liver, ovary, oviduct, lung, proventriculus, and kidney. In the experimental stage, one hundred and twenty (one-day-old) chicks were randomly divided into two equal groups. The first group was injected intraperitoneally with ALV-J strain (locally isolate strain) at a dose of 0.2 ml of log104 embryo infected dose50 (EID50). The second group was kept as normal control. The hematological, and biochemical constituents, ALV-J antibody titer and histopathology of the internal organs were investigated monthly for 5 months post infection (mpi). The infected group showed dullness, ruffled feathers, droppings, loss of appetite, decrease in feed intake and depression. The mortality rate was 18.3%. Macrocytic normochromic anemia, leukocytosis, heterophilia, and lymphocytosis were recorded. Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase activities, and creatinine and uric acid levels were markedly (P<0.05) increased. Lymphoid and myeloid leucosis in the heart, liver, spleen, and kidneys and also erythroid leucosis in the heart and osteopetrosis were seen. In conclusion, ALV-J infection in a flock of chicken could be diagnosed by pathological picture of characteristic tumors then confirmed by various methods for detection of the virus. By immunohistochemistry method, antigens of ALV-J were detected in the tissues of lung, kidney, spleen, liver, ovary, oviduct, and proventriculus. The experimental infection with ALV-J caused alteration in the blood picture and dysfunction of liver and kidney as well as histopathological lesions in the internal organs and bone of infected chickens. These changes began at the 3rd mpi and it could be help in the early diagnosis of this disease.
2021
Ph.d
Beni Suef
Veterinary Medicine