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Anand Agricultural University, Anand
Anand Agricultural University (AAU) was established in 2004 at Anand with the support of the Government of Gujarat, Act No.(Guj 5 of 2004) dated April 29, 2004. Caved out of the erstwhile Gujarat Agricultural University (GAU), the dream institution of Sardar Vallabhbhai Patel and Dr. K. M. Munshi, the AAU was set up to provide support to the farming community in three facets namely education, research and extension activities in Agriculture, Horticulture Engineering, product Processing and Home Science. At present there seven Colleges, seventeen Research Centers and six Extension Education Institute working in nine districts of Gujarat namely Ahmedabad, Anand, Dahod, Kheda, Panchmahal, Vadodara, Mahisagar, Botad and Chhotaudepur
AAU's activities have expanded to span newer commodity sectors such as soil health card, bio-diesel, medicinal plants apart from the mandatory ones like rice, maize, tobacco, vegetable crops, fruit crops, forage crops, animal breeding, nutrition and dairy products etc. the core of AAU's operating philosophy however, continues to create the partnership between the rural people and committed academic as the basic for sustainable rural development. In pursuing its various programmes AAU's overall mission is to promote sustainable growth and economic independence in rural society. AAU aims to do this through education, research and extension education. Thus, AAU works towards the empowerment of the farmers.
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ThesisItem Open Access SEROEPIDEMIOLOGY, ISOLATION AND PATHOGENICITY OF BLUETONGUE VIRUS(AAU, Anand, 1996) Chandel, Bharat Singh; Kher, H. N.Bluetongue (BT) is an infectious, non contagious disease of domestic and wild ruminants. Bluetongue virus ( BTV ) causes severe disease in sheep, which i s transmitted by insect vectors (Culicoides spp.) . The ability of BTVs to inflict pathological changes in susceptible sheep depends on the virulence of a particular viral isolate , susceptibility of the host and a number of environmental factors related to climatic conditions. The present study was aimed at the seroepidemiology, prevalence of BTV serotypes in sheep, isolation, propagation and identification of local isolates and pathogenicity of BTV in natural and experimental cases of sheep. This study also covered the seroprevalence of epizootic haemorrhagic disease virus (EHDV) in cattle and buffaloes as it is related to orbivirus group. A seroepidentiological survey of BTV precipitating antibodies was carried out by agar gel immunodiffusicm ( AGID ) test in different species of livestock in Gujarat. Out of 1623 sera tested, 407 (25.07%) were found to be positive for BTV antibodies.ThesisItem Open Access ISOLATION OF INFECTIOUS BURSAL DISEASE VIRUS (IBDV), ITS COMPARISON WITH VACCINE STRAINS AND EFFICACY OF DIFFERENT VACCINATION REGIMENS IN PASSIVELY IMMUNE CHICKS(AAU, Anand, 1995) Hirpurkar, Sadananda D.; Kher, H. N.Infectious bursal disease (IBD) which was characterised by relatively less mortality but more immunosuppression was earlier prevalent in India. During a past couple of years, there is country-wide change in pattern of disease with high mortality rates. Some of the farms investigated in the present study have also experienced high mortality among both, layers (six to 14 weeks) and broilers (four to six weeks). Present study was undertaken on isolation of IBDV from field samples, study their pathogenicity and antigenicity in comparison with existing vaccine strains; and formulation of vaccination regimen effective enough to give protection to chicks in presence of maternal antibody. Before taking up virus isolation, tissue homogenates from clinical cases were examined by agar gel diffusion test (AGDT) against reference antiserum and their identity as IBDV was confirmed. Overall AGDT positive samples ranged between 40.0 and 70.5 per cent. Positive field samples were grouped under five groups (UNO, KAM, AND, HAL and NAV), according to different geographical regions. An attempt was made for isolation of IBDV from all the five representative samples in different indicator systems. Among experimentally inoculated chicks, the clinical disease was reproduced in case of UND, KAM and AND isolate infected group. No clinical symptoms were observed in NAL and NAV isolates infected groups. The birds inoculated with each samples and sacrified 48 hours PI, had gross and histopathologic changes suggestive of IBD. Specific precipitation lines were demonstrated in bursal homogenates. Out of five field isolates, three isolates (UND, KAM and AND) were adapted to growth in chick embryos by chorioallantoic membrane (CAM) route. Predominant changes were observed in the embryos which included slow and stunted growth, cutaneous edema and hemorrhages in subcutis. UND isolate was serially passed onto chicken embryo fibroblast (CEF) cell culture for its adaptation to growth. Characteristic cytopathic effect (CPE) was observed earliest, at 30 hours PI, and maximum CPE showing degeneration of about 80 per cent cell monolayer, at 48 hours PI. Syncytia formation due to aggregation of large number of nuclei of dead cells was observed in later stages. Other field samples failed to induce CPE in cell culture upto five serial passages. Comparative pathogenicity studies on five field isolates, one reference isolate (BAN) and vaccine strain of intermediate (Vac-I) and mild (Vac-M) virulence each, were carried in chicks, chick enbryos and CEF cell culture. Birds infected with UHD and BAM isolates showed severe clinical synptons and also hemorrhagic lesions in the bursa of Fabricius (BF), skeletal muscles and proventriculus-gizzard junction. Concurrent histopathologic lesions in the BF, at 48 hours PI, includes marked edema, hyperemia, necrosis of lymphoid cells, and formation of vacuoles or cystic follicles. In case of birds inoculated with Vac-I strain, the enlargement and edema was more marked which persisted longer. Vaccine strain induced histopathological lesions in BF which were of mild degree and comparable to those found in birds infected with NAL and NAV isolates. As regard to the pathogenicity of field isolates in chick embryos inoculated by CAM route, UND and BAN isolates caused almost 80 per cent mortality. Among other isolates, AND and KAM showed relatively low mortality rates followed by HAL and NAV. Unlike any of the recent field isolates tested in the present study, the UND isolate grew well in CEF cells exhibiting CPE in infected monolayers. Thus, only the UND and BAN isolates, were able to maintain consistent pathogenic potential in every laboratory system tested. Slight variation as regard to period required for initiation of CPE was observed in UND and BAN isolates when compared with that of vaccine strains. Highest virus infectivity titre was recorded in Vac-I strain, while in Vac-M strain the titre was lowest. The virus titres in both field isolates (UND and BAN) were sane. Neutralization and cross neutralization tests were carried out to assess the antigenic relatedness of a field isolate, reference isolate and vaccine strains using homologus and heterologus innune sera. The results indicated close antigenic relationship of the isolates with vaccine strains. In the present study, efficacy of three vaccination regiuens was evaluated in the progeny obtained from breeder hens having high levels of maternal antibody (MA). The levels of precipitating antibodies of progeny chicks at hatch indicated, on an average, 50 to 55 per cent passive transfer of MA to progeny. After hatch, higher levels of MA sustained for one week and afterwards declined steadily at the half-life of approximately six to eight days. MA attained low levels between 21 and 28 days of age. While after 28 days of age, precipitating antibodies were undetected by quantitative AGDT (QAGDT), still these antibodies were detected by enzyme linked immunosorbent assay (ELISA). Live vaccine (mild) was used at day-old age for 'priming' of all the birds and subsequently, combination of live (intermediate) and/or inactivated vaccines was tested in three groups. One group served as control. The response of birds, vaccinated once or twice with live intermediate vaccine was not satisfactory as indicated by low levels of antibodies even after vaccination. On challenge, some birds showed clinical symptoms and bursal damage. The group in which birds received inactivated vaccine, at seven days of age and live vaccine at 14 and 28 days of age, showed significantly (P <0.05) higher levels of antibody. On challenge, the birds did not show clinical symptons and mortality, but still these birds were not prevented from infection because the bursal danage was apparent indicating inadequate response against virulent IBDV. Overall studies indicated the presence of highly virulent IBDV in sone pockets of Gujarat State. Therefore, it is important to locate such pockets at an earliest to prevent possible spread of highly virulent IBDV and carry out effective vaccination coupled with strict biosecurity measures, where immunization has failed probably because of increased virulence of IBDV. Serological monitoring of progeny flock is necessary to determine when MA in chicks decline to levels that the vaccine can overcome. Without this information, it is very difficult to control highly virulent IBDV.ThesisItem Open Access ANTIGEN DETECTION, PATHOGENICITY AND PERSISTENCE OF MATERNAL ANTIBODIES OF INFECTIOUS BURSAL DISEASE VIRUS(AAU, Anand, 1995) Abraham, Reena; Kher, H. N.Infectious bursal disease is an acute or more commonly a subclinical viral disease of young chickens characterized by lymphocidal effects in the lymphoid organs, especially in the bursa of Fabricius. The disease is known to cause immunosuppression, vaccinal failure and surfacing of latent and subclinical concurrent infection in the infected bird. Present study was aimed at the antigen detection, pathogenicity and persistence of maternal antibodies of infectious bursal disease virus (IBDV). The bursa samples were collected from the dead or ailing birds with specific IBD lesions routinely obtained at the Department of Pathology and were tested for the presence of the viral antigen using agar gel diffusion test (AGDT). The samples obtained from Anand, Karamsad, and Undach gave positive line oi precipitation with known positive serum. The isolates designated as AND (Anand), KAM (Karamsad) and UND (Undach) on the basis of the area from where these samples were obtained, were compared with a reference isolate BAN (Bangalore) for the pathogenicity study. Clinical symptoms were observed in one or two birds -from each group followed by death. Rest of the birds were normal till the end of the observation period . The bursa of Fabricius was found enlarged on the third day PI with gradual atrophy setting in from seventh day PI in all the infected groups. Spleen showed slight enlargement on seventh day PI. Thymus was found to be enlarged on 11th and 14th day PI. The bursa to body weight indices showed significant difference at different intervals. The indices showed that the bursa to body weight ratio in all the infected groups was about two times as compared to that of control on third day PI and from fifth day PI, there was a decrease in this ratio in all the infected group till the end of the observation period suggesting atrophy, The histopathological lesions were mainly seen in bursa of Fabricius (BF) in the form of marked inter and intrafollicular oedema and mild to moderate depletion of lymphoid cells on the third day PI. Mild increase in the interfollicular connective tissue proliferation along with heterophilic infiltration was also seen. The changes became severe on fifth day PI. On seventh day PI, the bursal follicles were atrophied with severe depletion of the lymphocytes in cortex and medulla. On 11th and 14th day PI, large cystic follicles with mononuclear cell infiltration into the interfol1icular area were observed. The spleen lesions were in the form of mild depletion of lymphoid cells along with focal areas of coagulative necrosis and reticulo-endothelial (RE) cell hyperplasia. The thymus and caecal tonsils revealed same type of lesions as spleen. The kidney revealed acute renal congestion and presence of lymphoid foci. The lesions were very mild in the AND and KAM groups of birds. The antigen was detectable in UND group on third day PI and BAN group on third and seventh day PI by AGDT. Using quantitative AGDT, serum antibodies were detected from seventh day PI onwards in the local isolate infected groups and from fifth day PI in the reference isolate infected group. 'The antibody titres showed gradual increase in all groups till the end of the observation'period. For immunosuppressive study, each infected group was vaccinated with sheep erythrocytes and subsequently at weekly interval birds from each group were screened for presence of antibody using HA test. Overall antibody level of control group was significantly higher (P < 0.01) from treatment means of infected group. Among BAN, KAM and AND isolates infected groups, mean HA titres did not show significant difference, but in UND isolate infected group the mean titre was significantly higher than other groups. Further, the infected birds were vaccinated with 'F' vaccine of NDV and each group was screened at weekly interval for presence of antibody using HI test. The HI titres of all the infected groups were significantly lower than that of control group at second and third week suggesting immunosuppressive effect of these isolates. The titres in AND and KAM groups were significantly lower than that in UND and BAN groups during this period indicating their more immunosuppressive effect. Only the UND isolate was adapted to the chick embryos producing mortality in four out of six chick embryos when inoculated via CAM route at fourth passage level. The embryoij were stunted with cutaneous haemorrhages in the cerebral area and on the toes. The other isolates did not adapt to embryos evenafter four passages. The maternal antibodies were found to persist in the chicks hatched from vaccinated parental flock upto 20 days of age as ascertained by ELIBA and quantitative AGDT. The maternal antibodies with the quantitative AGDT titre 1:8 and ELISA titre +3, were found to be protective only upto 15 days of age in chicks against IBDV infection.