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Theses

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1993 - 19993
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Subject: Veterinary Microbiology × Start date: 1980 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Production and application of monoclonal antibodies against duck plague virus
    (Department of Microbiology, College of Veterinary and Animal Sciences, Mannuthy, 1999) Ravindra Dattatraya, Padalkar; KAU; Jayaprakasan, V
    Monoclonal antibodies (Mabs) were raised against the vaccine strain of DPV and three strains of DPV Viz, Vaccine (DPV-V), IVRI (DPV-I) and Alleppy strain (DPV-A) were used to raise polyclonal serum in the present investigation. DPV-V was revived in 11 day old chicken embryo and the embryo death was recorded Tour to five days PI- with congestion all over the body and spleen and necrotic foci in liver. The cytopalhy in CEF cell culture observed was rounding and clumping of the cells, syncylium formation and bridge formation with extensive vacuolation in the Cytoplasm. The detachment of the cells was observed at 120 h PI. DPV-I a virulent strain was inoculated in the ducklings, death was recorded in all the inoculated birds with extensive hemorrhages on serous membranes, muscles and visceral organs. Necrotic foci on liver,' enlargement and congestion of liver, and spleen, and white hecrotic foci in the gizzard were evident. The virus was further passaged in DDE and cultivated in bulk in DEF cell culture. The DPV-V and DPV-A were titrated in CEF cell culture and the TC1D J0 was 4.7 X 105 per ml of the inoculum Tor DPV-V and 3.2 X 10"1 for DPV-A. DPV-I cultivated in DEF cell culture had a TCID50 of 1X10 3'per ml of the inoculum All (lie strains were partially purified at 100000 g for 4.5 h at 4" C in Beckman ultra centrifuge and the protein concentration oF the virus was estimated by biuret method and was found to be 11 mg, 8 mg and 7 mg for DPV-V, A and 1 respectively. All the three strains of DPV were inoculated in mice to raise polyclonal serum. Four mice out of five inoculated with DPV-V showed ELISA litres more than 1:12800, one mouse showed a titre of 1:6400. The mice inoculated with DPV-A showed a titre of more than 1,12800 and those inoculated with DPV-I, 1:6400 ELISA ’Was1’ used to test the sera samples of the mice inoculated with DPV strains. The test was found to be highly sensitive, easy to perform and less time consuming. The test therefore can be recommended for routine diagnosis of DPV
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    ThesisItemOpen Access
    Assessment of immunity to duck plague virus (duck virus enteritis)
    (Department of Microbiology, College of Veterinary and Animal Sciences, Mannuthy, 1993) Diwakar Dattatrayrao, Kulkarni; KAU; James, P C
    During 1991, six outbreak clinically suspected to be duck plague (DP) with 33 per cent morbidity and 26 per cent mortality were investigated Duck plague virus was isolated from each outbreak. The isolates were able to produce the lesions and death of the duck embryos but failed to kill the chicken embryos during initial passages. One of the strains, named DP-S was partially attenuated by 10 passages in chicken .embryos following 20 passages in duck embryos. Though the attenuated strain did kill ducks, its pathogenicity index was reduced from 1.9 to 1,23. The isolate DP-S under transmission electron microscope revealed virions of herpes virus morphology. Two DP vaccines - commercial vaccine and lab-adapted vaccine having virus titres 0.74 and 3.5 log 10 ELD 50/ml respectively, were separately inoculated into four groups of ducklings respectively, two groups receiving single dose and two receiving double dose of corresponding vaccines at an interval of four weeks. Another group of ducklings was kept as control without vaccination. Three ducks in each group were challenged with virulent DPV at four,eight and 20 weeks post-vaccination. The birds in all the five groups were screened at regular intervals for studying the immune response by virus neutralization (VN), leucocyte migration-inhibition (LMI) and passive haemagglutination (PHA) test The challenged and survived birds were screened for the carrier status of DPV by examination of their rectal swabs for virus isolation. In an organized farm, 180 ducks were given commercial vaccine at one year of age and were screened for VN antibodies, LMI response and PHA titres before and eight weeks post -vaccination. Randomly selected two birds were challenged six weeks post-vaccination. The findings of the study are briefly listed as under: Six duck plague outbreaks were investigated, the virus isolated, and characterized. It was partially attenuated in duck and chicken embryos. The commercial, vaccine could elicit very poor immune response as compared to laboratory adapted vaccine. The immunity could not last long even upto eight weeks in single vaccination and 20 weeks in double vaccination.
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    ThesisItemOpen Access
    Characterization of plasmids of Escherichia coli isolated from mastitis
    (Department of Veterinary Microbiology, College of Veterinary and Animal Science, Mannuthy, 1993) Avinash Ganpatrao, Karpe; KAU; Punnoose, K T
    Escherichia coli. were isolated in 15.33 per cent cases of mastitis. Of the 46 E. coli isolated 43 were resistant to one to nine antibiotics and three were sensitive to all the 13 antibiotics tested. The organisms were resistant to rifampicin (78.26%) followed by oxytetracycline (50%), tetracycline (37.78%), nalidixic acid (19.56%), co-trimoxasole (8.69%) and gentamicin (6.52%). All the organisms were susceptible to kamamycin and norfloxacin. Among the .multiple drug resistance oxytetracycline - rifampicin (OR) resistance was noticed in 76.2% cases. Twenty-six different patterns of antibiotic resistance were noticed among 43 E. coli isolates giving a reliability of 60.46 per cent in differentiating the isolates. Hence, antibiogram could only be used as an adjunct to plasmid profiling in epidemiological studies. The resistograms revealed cent per cent resistance to lead, followed by antimony (32.6%), copper (30.43%), silver(19.56%) and cetrimide (2.17%). All the isolates were sensitive to cadmium and mercury. Among the 46 E. coli isolates, 9 different resistogram patterns were obtained giving reliability of 19.56 per cent in differentiating the strains. A correlation between the antibiotics and heavy metal ac; lead an+-imcny and copper, was observed inresistance such as leaa, descending order. of the forty-six E. coli isolates three (6.52%) were hemolytic on sheep blood agar. Two of the three hemolytic strains were also enterotoxigenic. Thirteen of the 46 (28.26%) E. coli isolates were enterotoxigenic, when tested by rabbit ligated ileal loop assay. Two of the thirteen (15.38%) enterotoxigenic isolates were also hemolytic. Fourteen of the 24 (58.33%) drug resistant E. coli transferred drug resistance against one or more antibiotics to the recipient organism. In none of the cases the furazolidone resistance was transferred. All the three hemolytic E. coli isolates transferred the hemolytic character by conjugation indicating the plasmid borne nature of hemolysin production. None of the enterotoxin producing E. coli could transfer the character to recipient by conjugation.