Biological risk stemming from the long-term burial of NDV vaccinal strains
Abstract number: 1733_1055
Bianchi S., Amendola A., Canuti M., Zappa A., Tanzi E., Koncan R., Cornaglia G.
Objective: Large areas are often used as uncontrolled pits for pharmaceutical waste. No worldwide-accepted criteria define the extent and persistence of the consequent biological risk, related, for instance, to vaccines and their by-products. The objectives of the present study were:
1. To study the residual viability of Newcastle Disease Virus (NDV) vaccine strains stored in sealed vials and recovered after burial for 30 years.
2. To determine the persistence of the NDV genome in embryonated chicken eggs, i.e. the substrate used for producing the vaccine.
Methods: Vaccines against Newcastle Disease (avian pseudoplague) were analysed both in lyophilised form and as specimens of eggs recovered from the same area. To evaluate the competence and integrity of the viral genome, gene amplification was performed by nested RT PCR specific for a 275 bp fragment of NDV gene F. The PCR-positive specimens were submitted to viability tests through preparation of permissive cell cultures (Vero, African green monkey kidney) and detection of the cytopathic effect. To confirm the specificity of the cytopathic effect, an haemadsorption test was performed. As a positive control, we used a vaccine currently being used against the avian pseudoplague (Izovac, Brescia, Italy) containing live NDV strains (titre, >106 EID50).
Results and Conclusions: Nested RT PCR permitted detection of the NDV genoma in the lyophilised vaccine vials, but not in the egg specimens. This suggests that the NDV viral RNA can persist for several years even under uncontrolled environmental conditions if preserved in sealed vials, but is not able to persist in substrates undergoing chemical and bacteriological modifications, such as the eggs. The recovered viruses were endowed with the specific NDV cytopathic effect, thus showing that they retained their replicative ability. As a consequence, an NDV infection risk is actually involved in the manipulation of pharmaceutical waste. The lack of studies aimed at evaluating the environmental infection risk from the uncontrolled burial of industrial bio-material, such as vaccines and their by-products, constitutes a serious gap in our knowledge.
|Session name:||European Society of Clinical Microbiology and Infectious Diseases|
|Location:||ICC, Munich, Germany|
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