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1977 - 19782
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Subject: Veterinary Microbiology × End date: 1978 × Start date: 1977 × Thesis Type: M.V.Sc. ×
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    ThesisItemOpen Access
    Survey on the incidence of Salmonellae in meat animals
    (Department of Microbiology, College of Veterinary and Animal Sciences, Mannuthy, 1977) James, P C; Abdulla, P K
    Prior to this “Survey on the Incidence of Salmonellae in Meat Animals” the information on the serotypes of Salmonella prevalent and the magnitude of their occurrence in livestock in Kerala had been meagre except for the reports by Sulochana et al. (1973) and Balakrishna Pillai (1975). The work carried out during the present investigation has gathered more information on the prevalence of Salmonella in livestock in Kerala. In this study the prevalence of Salmonella serotypes in the different species of animals was probed. A total of 823 biomaterials, besides 50 drain samples were subjected to cultural screening. This venture resulted in the recovery of 56 strains of Salmonella. Serological identification of many of these strains proved the prevalence of S. typhimurium, S. weltevreden and S. urbana. The preponderatingly prevalent serotypes were found to be the former two. Pathogenicity studies employing S. typhimurium culture in mice, guinea pigs, rabbits, calves and piglets were conducted. All these animals were found to be susceptible to infection by S. typhimurium evincing varying degrees of clinical manifestations. The advantages of employing modified McConkey’s medium (Sharma, 1961) containing Mannitol instead of lactose and composite medium 1 and 11 developed by Chitin is et al. (1972) to differentiate Salmonella at primary screening level have been discussed
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    Investigation on the aetiology of plague -like disease in ducks In Kerala
    (Department of Microbiology, College of Veterinary and Animal Sciences, Mannuthy, 1978) Krishnan Nair, G; KAU; Sulochana, S
    An investigation was carried out to isolate, characterize and identify the agent responsible for the outbreak of duck plague – like disease in ducks in Kerala. Specimens (liver and spleen) from field cases, were processed for virus isolation and were inoculated into either developing duck or chick embryos, by chorio – allantoic (C.A.M.) or allantoic cavity method. Virus isolation was possible only by C. A. M. inoculation of duck embryos and was confirmed by inoculation of the C.A.M. extracts into duck embryo fibroblast (D.E.F.) cell cultures. The cytopathic changes produced by the field isolate DPV – N; its physico – chemical characteristics such as sensitivity to chloroform and 5 – iodo – 2 deoxyuridine; and the effect of exposure to various pH values such as 4.7, 7.2 and 9.1, were compared with that of a known duck plague virus DPV – K, received from the Veterinary Biological Institute, Mannuthy. In D.E.F. cell cultures, the cytopathic changes produced by DPV – N and DPV – K were rounding and clumping of cells, with characteristic basophilia and granulation of the cytoplasm. Although the initial titers of both DPV - N and DPV - K were only 105 and 106.25, they increased to 107.5 and 108.25 respectively, on further passages. The field isolate DPV – N and the known duck plague virus DPV – K were sensitive to 5% chloroform, with complete inactivation in ten minutes. Similarly, both the strains failed to multiply and produce cytopathis changes in cells treated with IUdR, at the rate of 100 micrograms per ml. However, differences were observed in their thermostability and pH sensitivity. Although DPV – K was inactivated completely at 560 C. in 30 minutes, DPV – N was only partially reduced in titer. DPV – N was also found to be resistant, when both the strains were exposed to pH 4.7, for a period of four hours at room temperature. But both were unaffected at pH 7.2 and got inactivated at pH 9.1. Both the strains also failed to produce any haemagglutination reaction with chicken R.B.C or precipitation reaction in agar gels. Although duck plague specific antiserum neutralized homologous strain DPV – K and the newly isolated strain DPV – N, the serum titers obtained with the latter was only less. Experimental infection studies have shown that one to six week – old ducklings were equally susceptible to DPV – N and DPV- K, either with the spleen extract or with tissue culture passaged sample. The symptoms and lesions produced in both cases, were similar to those described for duck plague and also to those seen during the disease outbreak in Kerala. The virus that caused an outbreak of duck plague - like disease in Kerala is found to be indistinguishable from that of duck plague. It is also strongly felt that the lack of complete protection of birds vaccinated with duck plague vaccine is due to t possible strain variation between the classical duck plague virus DPV – K and the virus as it occurred during this outbreak. However, it needs thorough in vitro cross neutralization and in vivo cross protection tests before any definite conclusions can be made on the strain variation of duck plague virus.