Effects of Pelleting, Irradiation, and Autoclaving of Rodent Feed on MPV and MNV Infectivity
| Autor: | Sean C Adams, Laura N Tracey, Mathias Leblanc, Robert S. Livingston, Matthew H. Myles, Jon D. Reuter, Carrie L Schultz |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
SWISS WEBSTER Rodent Food Handling ved/biology.organism_classification_rank.species Rodentia Biology Microbiology Parvoviridae Infections Parvovirus Rodent Diseases Mice 03 medical and health sciences biology.animal Animals Potential source Irradiation Seroconversion Caliciviridae Infections Infectivity 030109 nutrition & dietetics ved/biology Norovirus biology.organism_classification Animal Feed Management Mice Inbred C57BL 030104 developmental biology Animal Science and Zoology Murine norovirus |
| Zdroj: | Journal of the American Association for Laboratory Animal Science. 58:542-550 |
| ISSN: | 1559-6109 |
| Popis: | Murine norovirus (MNV) and mouse parvovirus (MPV) are among the most common adventitial viruses seen in laboratory mice, and infections arise in barrier facilities despite rigorous biosecurity programs. Some authors have implicated nonsterilized feed as a source of MPV in rodent facilities, but none have conclusively documented viral particles in the feed. In this study, we hypothesized that both viruses can resist the pelleting process but not subsequent irradiation or autoclaving, thus revealing a potential source of outbreaks in rodent facilities. To test this hypothesis, we contaminated powdered feed with 10-fold concentrations of MNV and MPV and fed it to both Swiss Webster (SW) and C57BL/6NTac (B6) mice to determine a ‘powdered ID(50)’ according to seroconversion over a 28-d period. We repeated the experiment by using powdered feed that we contaminated with increasing viral doses (as no. of powdered ID(50)) and subsequently pelleted; from these results, we determined a ‘pelleted ID(50).’ Finally we assessed the effect of irradiation and autoclaving on contaminated pellets by using the same experimental design. The powdered ID(50) was relatively low and identical in both mouse strains (2.51 × 10(2) pfu) for MNV but higher in B6 (copy number, 3.20 × 10(6)) than SW (3.98 × 10(4) copies) for MPV. As hypothesized, mice were infected by contaminated rodent feed despite the pelleting process. Indeed, pelleting resulted in a 1- to 2-log increase in ID(50) in both strains for MNV and MPV. Irradiation and autoclaving of infected pellets effectively prevented seroconversion of mice exposed to all doses of MNV, whereas a single mouse seroconverted at the highest dose of MPV (1.35 × 10(7) copies). These data suggest that both MNV and MPV remain infectious after conditions reproducing the rodent chow pelleting process and that nonsterilized rodent chow might be a source of viral outbreaks. |
| Databáze: | OpenAIRE |
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