Coping with parvovirus infections in mice: health surveillance and control

Abstract

Parvoviruses of mice, minute virus of mice (MVM) and mouse parvovirus (MPV), are challenging pathogens to eradicate from laboratory animal facilities. Due to the impediment on rodent-based research, recent studies have focused on the assessment of re-derivation techniques and parvoviral potential to induce persistent infections. Summarizing recent data, this review gives an overview on studies associated with parvoviral impact on research, diagnostic methods, parvoviral persistence and re-derivation techniques, demonstrating the complex nature of parvovirus infection in mice and unfolding the challenge of controlling parvovirus infections in laboratory animal facilities. Keywords: MVM, MPV, parvovirus mouseLaboratory Animals 2012; 46: 14-23. DOI: 10.1258/la.2011.011025Autonomous parvoviruses of mice, minute virus of mice (MVM) and mouse parvovirus (MPV), are major impediments to rodent-based research and quite challenging pathogens to eradicate from contemporary laboratory animal facilities. MVM and MPV are members of the genus Parvovirus, referring to small (18-26 nm), non-enveloped, single-stranded DNA viruses with a genome of approximately 5000 nucleotides.

Viral Infections of Laboratory Mice

“…Severe clinical signs are therefore not found in mature animals because of the lack of a sufficient number of susceptible cells in tissues. General aspects of rodent parvovirus infections and their potential effects on research results have been reviewed [6,8,[166][167][168][169][170].…”

“…The prevalence of sera positive for parvoviruses ranged from 1% to nearly 10% in Western Europe and North America, with the majority of sera being positive for MPV in studies differentiating between the two parvovirus species [12,14,15,176]. These prevalence data are based on testing at commercial laboratories and do not reflect that, despite highly specific and sensitive test methods, enzootic parvovirus infections are difficult to detect due to virus-associated characteristics [169,170]. A recent survey conducted in the USA showed that during a 24-36 month period mouse parvoviruses were detected at almost all facilities that responded to a questionnaire, with MPV being more often diagnosed than MVM [13].…”

“…The significance for laboratory mouse populations was considered low or uncertain because natural infections are inapparent. However, various effects on mouse-based research have been published [6,7,166,167,170]. Because of their predilection for replicating in mitotically active cells, they are frequently associated with tumour cells and have a marked oncosuppressive effect [212].…”

Effects of Pelleting, Irradiation, and Autoclaving of Rodent Feed on MPV and MNV Infectivity

“…Murine norovirus (MNV) and mouse parvovirus (MPV) are among the most common adventitial viral pathogens in laboratory mice. 28,42 Both are nonenveloped viruses that are no-toriously stable in the environment and resistant to inactivation from heat, desiccation, and many common disinfectants, all of which characteristics might facilitate their transmission to and within animal facilities. 9,28,51 Although MNV may cause lethal infection in severely immunodeficient mice, 31 clinical signs are generally absent in immune-competent mice.…”

“…28,42 Both are nonenveloped viruses that are no-toriously stable in the environment and resistant to inactivation from heat, desiccation, and many common disinfectants, all of which characteristics might facilitate their transmission to and within animal facilities. 9,28,51 Although MNV may cause lethal infection in severely immunodeficient mice, 31 clinical signs are generally absent in immune-competent mice. 24 Nonetheless, MNV has been shown to infect macrophages, dendritic cells, and B cells and is therefore likely to interfere with immunologic and inflammatory studies.…”