Comparison of Use of Agglutination of Mammalian Erythrocytes Plus Heat Stability Test and Use of Agglutination of Mammalian Erythrocytes Plus Erythrocyte Elution Time to Characterize Isolates of Newcastle Disease Virus.

Aim: For a simpler, more rapid and more accurate method of characterizing new isolates of Newcastle disease virus (NDV), agglutination of mammalian erythrocytes (HA) plus heat stability test and agglutination of mammalian erythrocytes plus erythrocytes elution time (EET) were compared with use of Intra-cerebral pathogenicity index (ICPI) to characterize the isolates. Materials and Methods: NDV isolates characterized by their ICPI were re-characterized by HA of mammalian erythrocytes plus heat stability test and by HA of mammalian erythrocytes plus EET. Rate of agreement of each of the two combinations with ICPI was calculated. Results: HA of mammalian erythrocytes plus heat stability agreed with ICPI in characterizing 10 of the 12 NDV isolates (83.3%) while use of HA of mammalian erythrocytes plus EET agreed with ICPI in all the 12 isolates (100%). Conclusion: It was concluded that use of combination of agglutination of mammalian erythrocytes and EET to characterize NDV isolates has better agreement with use of ICPI to characterize the virus than use of combination of agglutination of mammalian erythrocytes and heat stability test.

Assessment of Antiretroviral Effects of a Synthetic Aluminum-magnesium Silicate.

Aim: For an affordable therapy for Human immune-deficiency virus (HIV) infections, antiretroviral effects of a synthetic aluminum-magnesium silicate (AMS) were tested. Materials and Methods: Plasma that tested positive to HIV and the AMS were mixed, on equal volume to weight basis, incubated one hour at room temperature and centrifuged for ten minutes at 3,000 revolutions per minute. These procedures were repeated on each supernatant. HIV titres of the two sets of supernatants and the titres in portions of the plasma, not incubated with the AMS were assessed by direct passive hemagglutination test. Results: Mean HIV titres of the plasma increased from 4.00±1.60 to 14.00±2.00 when incubated with the AMS. Repeating the incubation, reduced mean HIV titres in plasma from 14.00±2.00 to 6.50±1.50 (P=0.024). Conclusion: It was concluded that the AMS has antiretroviral effects and could be an inexpensive antiretroviral therapy for regular treatment to reduce high rate of HIV infection among low income groups.

Effects of Live Infectious Bursal Disease Vaccines, on Immune Response of Vaccinated Chicks.

Aim: Relationship between virus titers of live Infectious Bursal disease (IBD) vaccines and their serum-conversion abilities was studied. Study design and Methodology: Five batches of each, of five IBD vaccine brands used in Nigeria, were tested for virus titers. Each of the vaccine brands was also used to vaccinate a group of fifteen 12-days old chicks to study their serum-conversion abilities. Mean antibody titers of the groups of chicks were plotted, on a graph, against virus titers of the vaccine brands used to vaccinate them. Results: Mean Modified Passive Haemagglutination titers of IBD virus in the vaccines,were:1,065.60±780.03,1,472.00±748.55,2,112.00±1984.00,2,176.00±1920. 00 and 2,585.00±926.92 while mean antibody titers they elicited were, 1,356.80±241.51, 1,280.00±174.88, 448.00±79.25, 998.40±196.27 and 332.80±51.20, respectively. Line of best fit of graph of antibody titers of vaccinated chicks on vaccine titers, showed that reducing titers of the live IBD vaccines improved their immunogenicity. Conclusions: The inverse relationship between virus titers of the vaccines and their serum conversion abilities, suggests that, if viral titers of live IBD vaccines are too high, immune-suppression instead of enhancement of immune response may occur.