Lurking in the Shadows: Emerging Rodent Infectious Diseases

Abstract

Rodent parvoviruses, Helicobacter spp., murine norovirus, and several other previously unknown infectious agents have emerged in laboratory rodents relatively recently. These agents have been discovered serendipitously or through active investigation of atypical serology results, cell culture contamination, unexpected histopathology, or previously unrecognized clinical disease syndromes. The potential research impact of these agents is not fully known. Infected rodents have demonstrated immunomodulation, tumor suppression, clinical disease (particularly in immunodeficient rodents), and histopathology. Perturbations of organismal and cellular physiology also likely occur. These agents posed unique challenges to laboratory animal resource programs once discovered; it was necessary to develop specific diagnostic assays and an understanding of their epidemiology and transmission routes before attempting eradication, and then evaluate eradication methods for efficacy. Even then management approaches varied significantly, from apathy to total exclusion, and such inconsistency has hindered the sharing and transfer of rodents among institutions, particularly for genetically modified rodent models that may not be readily available. As additional infectious agents are discovered in laboratory rodents in coming years, much of what researchers have learned from experiences with the recently identified pathogens will be applicable. This article provides an overview of the discovery, detection, and research impact of infectious agents recently identified in laboratory rodents. We also discuss emerging syndromes for which there is a suspected infectious etiology, and the unique challenges of managing newly emerging infectious agents.

Old Enemies, Still with Us after All These Years

“…As discussed elsewhere, parvoviruses remain, both individually and as a group, among the most prevalent viruses in laboratory rats and mice (Besselsen et al 2008;Carty 2008;Clifford and Cosentino 2006a,b;Livingston and Riley 2003). In light of the significant biological similarities among rodent parvoviruses, we consider the reasons for their continued presence in general.…”

“…Research effects of parvovirus infection of rats and mice include well-demonstrated and long-lasting effects on the immune system, oncology studies, and lymphocyte cultures (Besselsen et al 2008;Ellerman et al 1996;Jacoby et al 1996;McKisic et al 1995). But despite the substantial literature of parvoviral interference with research, it is sometimes difficult to garner the necessary commitment from principal investigators.…”

Staphylococcus sciuri associated to subcutaneous abscess and dermatitis in ICR mouse

“…The strategies used to control or eliminate emerging and reemerging pathogens, as called outbreak response, especially opportunistic microorganisms from the laboratory animal colony depend on these organisms' risk to institutional programs (Besselsen et al, 2008). The strategies include consideration of the colony requirements, numbers of animals at risk, and available facility resources together with the selective control measures' cost, complexity, and probability of success (Hedin and Widerstrom, 1998).…”

“…The strategies include consideration of the colony requirements, numbers of animals at risk, and available facility resources together with the selective control measures' cost, complexity, and probability of success (Hedin and Widerstrom, 1998). The opportunistic pathogens were denoted an organism capable of causing disease only in a host whose resistance is lowered (Waggie et al, 1994;Hedin and Widerstrom, 1998;Besselsen et al, 2008). They do not affect research and breeding performance uniformly.…”

Using amphibians in laboratory studies: precautions against the emerging infectious disease chytridiomycosis

“…Despite stringent procedures, several emerging and re-emerging pathogens have been recently identified in rodent laboratory colonies, including the murine norovirus. 3,4 The threat represented by emerging pathogens led to the organization of a workshop dedicated to the 'Detection, Impact and Control of Specific Pathogens in Animal Resource Facilities' in 2009. One major conclusion of this workshop was the recommendation of 'the improvement of communications of disease outbreaks and potential risks for animal models for the scientific community'.…”