To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different anti...To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different antibody titers were challenged with a Nigerian isolate of virulent IBDV. Mortality rates of the different groups were plotted against their respective mean PHA antibody titers. A group with zero antibody titer had a mortality rate of 75% while those with PHA antibody titers of 185.6, 243.2, 256 and 307.2 had mortality rates of 40%, zero, zero and zero respectively. Linear equation generated for a line of best fit of the graph of mortality rates of the chicks on their IBD antibody titers gave antibody titer (X) at which mortality (Y) would be zero as 300. A mortality of 75% and the high antibody level needed to protect chicks suggest that the isolate may be a hypervirulent strain.展开更多
To modify the Passive Haemagglutination (PHA) test, a rapid test, used for qauntitative detection of viral antibodies, so that it can be used for determination of viral titres, dilutions of Infectious Bursal Disease V...To modify the Passive Haemagglutination (PHA) test, a rapid test, used for qauntitative detection of viral antibodies, so that it can be used for determination of viral titres, dilutions of Infectious Bursal Disease Virus (IBDV) were used to sensitize the Red Blood Cells (RBCs) before reacting them with known IBD serum. Also, to improve sensitivity of the test, different RBC concentrations were used for the test. A standard IBDV gave positive PHA reaction upto its 1:2048 dilution. With different IBDV samples, positive PHA reactions occured upto dilutions, ranging from 1:16 to 1:4096. Different RBC concentrations gave different titres for same IBDV samples. With 0.6% and 0.2% RBC concentrations, mean PHA titres of IBDV samples increased from 454. 85 ± 315.32 to 2396.57 ± 489.55 (p < 0.05 ). It was concluded that PHA can be adopted for evaluation of viral titres. To improve sensitivity of the test, use of 0.2% RBC is recommended.展开更多
文摘To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different antibody titers were challenged with a Nigerian isolate of virulent IBDV. Mortality rates of the different groups were plotted against their respective mean PHA antibody titers. A group with zero antibody titer had a mortality rate of 75% while those with PHA antibody titers of 185.6, 243.2, 256 and 307.2 had mortality rates of 40%, zero, zero and zero respectively. Linear equation generated for a line of best fit of the graph of mortality rates of the chicks on their IBD antibody titers gave antibody titer (X) at which mortality (Y) would be zero as 300. A mortality of 75% and the high antibody level needed to protect chicks suggest that the isolate may be a hypervirulent strain.
文摘To modify the Passive Haemagglutination (PHA) test, a rapid test, used for qauntitative detection of viral antibodies, so that it can be used for determination of viral titres, dilutions of Infectious Bursal Disease Virus (IBDV) were used to sensitize the Red Blood Cells (RBCs) before reacting them with known IBD serum. Also, to improve sensitivity of the test, different RBC concentrations were used for the test. A standard IBDV gave positive PHA reaction upto its 1:2048 dilution. With different IBDV samples, positive PHA reactions occured upto dilutions, ranging from 1:16 to 1:4096. Different RBC concentrations gave different titres for same IBDV samples. With 0.6% and 0.2% RBC concentrations, mean PHA titres of IBDV samples increased from 454. 85 ± 315.32 to 2396.57 ± 489.55 (p < 0.05 ). It was concluded that PHA can be adopted for evaluation of viral titres. To improve sensitivity of the test, use of 0.2% RBC is recommended.
