AMEER HAMZA, P(MAJOR)SHOBA MANI, BSREENIVASULU, DSREELATHA, ChSRINIVASA REDDY, PALEM2018-10-052018-10-052007-06http://krishikosh.egranth.ac.in/handle/1/5810074841THESESABSTRACT : Chicken Infectious Anemia Virus (CIAV) is a DNA circovirus and is ubiquitous in all major chicken producing countries of the world including India. It has probably spread through contaminated vaccines or through importation of parent birds from western countries. Chicken infectious anemia (CIA) can cause losses due to clinical disease, subclinical infection and immunosuppression. Infection is characterized by aplastic anemia, generalized atrophy of haemopoietic and lymphoid tissue, particularly, thymus. The main sites of virus replication are precursor T cells in the thymic cortex and in haemocytoblasts in the bone marrow. Co-infection with viruses of Marek’s disease, infectious bursal disease and reticuloendotheliosis enhances the pathogenicity of chicken anemia virus. Infection is vertically transmitted which results in clinical disease in young chicken. Vaccination of breeders during rearing protects the progeny from vertical infection and gives them passive protection through maternal antibodies. Horizontal infection in young chick flocks usually causes a subclinical infection, but immunosuppression breaks the resistance and CIA may occur in clinical form. In India gangrenous dermatitis in replacement pullets shows high association with CIA along with IBD. It is also responsible for increased incidence of MD vaccination failures. In view of the importance of the disease and Andhra Pradesh being one of the major state of producing chicken meat and eggs, it was felt necessary to study about chicken infectious anemia in this state of the country in terms of its epidemiological status, seroprevalence, diagnosis, pathogenesis and identify measures to control and prevent the disease. Present investigation was also extended to screen Japanese quails and desi chicken. Major emphasis was laid on broiler breeds, because of the peculiarity of the disease, which affect the birds of 2-3 weeks age among broilers. A total of 381 pooled serum samples from five birds each were collected from different poultry stations of different districts in Andhra Pradesh. Serum samples were also collected from local desi , broiler and layer breeds of chicken. Pooled serum samples were collected from farms with a history of vaccination breaks in spite of regular vaccinations for different diseases and also from healthy flocks. An outbreak suspected of chicken infectious anemia was investigated in one of the organized poultry farms near Tirupati. The investigation was concentrated on one batch of 16-week-old layers consisting 15,000 populations. Birds with poor weight gains suspected of chicken infectious anemia were identified and blood was collected from fourteen growers. Serum was separated and subjected for ELISA for confirmation of CIA with IDEXX ELISA kit. All the fourteen samples were found positive for antibodies to CIA virus. Ten birds among those fourteen positive were sacrificed and required biological materials viz., liver, thymus, spleen, bursa, bone marrow were collected and inoculum was prepared out of it for experimental studies in one-day-old Chicks. The experimental design consisted three groups of ten chicks in each group. The chicks Broiler breed - Vencobb strain were brought from V.S.N hatcheries, Lingaparan branch, Peddapanjani mandal of Chittoor district. The group I was incoulated with prepared infective material, group II was inoculated with infective material along with Betamethasone (Betnisol, Glaxo), for 5 subsequent days to know the effect of that immunosuppressive agent in aggravating the disease. The group III chicks were kept as controls. The birds from group I and group II began to exhibit the symptoms of diarrhea, soiling around the vent, weakness, weight loss, paleness of comb and wattles, thirstiness and notable mortality from second week onwards. Post mortem findings were evident by replacement of bone marrow with fatty tissue and gelatinous appearance, hypertrophy of liver, blood splash and muscular hemorrhages and mild atrophy of thymus and bursa. Ascitis, hydropericardium and congestion of lungs were also observed. Liver, spleen, lungs, heart, thymus, bursa, bone marrow were collected in 10% neutral buffered formalin subjected to histopathology revealed major changes that included depletion of bone marrow tissue, atrophy of thymus. Heparinised blood samples were collected from all three experimental groups of birds between 7 to 35 days at weeks intervals of post inoculation were studied for hematobiochemical parameters viz., packed cell volume, hemoglobin percentage and red blood corpuscle (RBC) counts and blood glucose. Serum was also separated and total serum protein, albumin & globulin levels were estimated. The results of packed cell volume, hemoglobin and RBC counts showed a significant difference statistically between infected and control groups. The difference in blood glucose and serum protein levels was not significant between infected and control groups. Body weights of all 3 groups were recorded at intervals of 5, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, & 70 days post inoculation. The difference in mean body weight between the infected and control groups was statistically significant. Serum, plasma, bone marrow, and reproductive organs testis and ovaries collected from experimentally infected birds at fifty days post inoculation were subjected to electron microscopy. Viral particles of 20.00to 21.50 nm size were detected in the plasma, bone marrow and serum in decreasing concentration.Viral particles could not be seen in testicular and oviduct washings through direct transmission electron microscopy. Serum samples collected from experimentally infected chicken were screened by ELISA (IDEXX Laboratories). All the samples from infected groups were found positive while that of control group were negative to antibodies against CIA virus. A total of 381 pooled samples collected from various districts of three regions viz, Rayalaseema, Coastal and Telangana of Andhra Pradesh were screened for CIA antibodies. The samples were tested using commercially available CAV - antibody ELISA kit (IDEXX Laboratories). Based on the results of screening a seroprevalence of 48.77% of CIA was observed in Andhra Pradesh. District wise seroprevalence was 98.65%, 80.4% , 67.5%,65%,50%, 48%, 34.78% and 2.7% in Prakasam, Nellore, Chittoor, Warangal, Anantapur, Nizamabad, Kurnool and Kadapa respectively. It has been noticed that all areas, all hatcheries, all breeds of chicken were showing seropositivity. However, the Japanese quails were seronegative to CIA. Based on the results of the above investigation it is concluded that CIA might be widely prevalent in Andhra Pradesh. The disease my be one of the main causes of vaccination breaks and increased mortality among chicken flocks in the state. Hence it is suggested to undertake in depth study on the epidemiology of CIA including isolation of the agent and its molecular charecterisation. This will pave way for development of suitable measures to control and prevent the invisible losses caused by CIA in commercial as well backyard poultry.ennullThesis