Detection of Murine Astrovirus and Myocoptes musculinus in individually ventilated caging systems: Investigations to expose suitable detection methods for routine hygienic monitoring

Abstract

Murine Astrovirus is one of the most prevalent viral agents in laboratory rodent facilities worldwide, but its influence on biomedical research results is poorly examined. Due to possible influence on research results and high seroprevalence rates in mice, it appears useful to include this virus into routine health monitoring programs. In order to establish exhaust air particle PCR as a reliable detection method for Murine Astrovirus infections in mice kept in individually ventilated cages (IVC) and compare the method to sentinel mice monitoring regarding reproducibility and detection limit, we conducted a study with defined Murine Astrovirus cage prevalence. In parallel, the efficacy of both detection strategies (soiled-bedding sentinel (SBS) and exhaust air dust (EAD) analysis) was tested for Myocoptes musculinus . The fur mite was used as a reference organism during the whole study period to ensure the validity of this method. Because some publications already demonstrated successful detection of several pathogens, including murine fur mite species, via EAP-PCR. Detection of Murine Astrovirus infections at low prevalence is possible with both methods tested. Detection by exhaust air particles (EAP) is faster, more sensitive and more reliable compared to soiled bedding sentinels (SBS). Exhaust air particle PCR also detected the reference organism Myocoptes musculinus , which was not detected at all by sentinel mice, not even by high sensitivity fur swab qPCR. In conclusion, Murine Astrovirus can be detected by both exhaust air particle PCR and soiled bedding sentinels. We recommend exhaust air particle PCR as the better detection technique for Murine Astrovirus, because it is more reliable. Environmental samples are the method of choice for detection of Myocoptes musculinus because relying on soiled bedding sentinels harbors a big risk of missing existing infestations.

PCR Testing of Media Placed in Soiled Bedding as a Method for Mouse Colony Health Surveillance

“…Pelage swabs collected from sentinel mice were negative for fur mites by PCR, even though the colony animals had been verified positive. Traditional soiled bedding transfer is known to provide inconsistent detection of fur mites in sentinel animals, 8,[17][18][19]37 and as such our finding is not entirely novel. However, all media samples collected from the soiled bedding of mouse-free experimental cages were positive for fur mites by PCR.…”

“…Several studies have shown that environmental sampling is a viable alternative to traditional sentinel programs. 16,17,23,25,[27][28][29][30][31][32]35,42 The collection and assay of only environmental samples eliminates the need for sentinel animals, leading to a desirable overall reduction in the number of animals used, and the associated reduction in husbandry, labor, and supplies. 22 Although environmental sampling can be done in many ways, the exhaust plenums of individually ventilated caging (IVC) systems have been shown to be a useful sampling location.…”

“…36 Common areas for sample collection on IVC racks include the horizontal exhaust manifold, 2,14 the cage filter top, 8,9 and the exhaust air prefilter. 2,4,17,24,29,42 Manufacturer variation in IVC rack design ultimately dictates where sampling should occur, as airflow pattern, location of dust accumulation, filter type and location, and plenum access must be considered. 2 All of these factors, perhaps including organizational resistance to change, can be hurdles to the widespread adoption of environmental testing for colony health surveillance.…”

Health Monitoring of Laboratory Rodent Colonies—Talking about (R)evolution

“…Until now, EAD-based monitoring approaches proved to be suitable for a broad variety of infectious agents, such as MNV [ 161 , 167 ], MHV [ 158 ], Murine Astrovirus [ 168 ], Lactate–Dehydrogenase–Elevating–Virus (LDEV) [ 169 ], Rodentibacter sp. [ 153 , 162 ], Helicobacter sp.…”

“…[ 160 ], Pneumocystis sp. [ 160 ], fur mites [ 158 , 168 , 170 ], pinworms [ 158 , 164 , 171 ] and enteric protozoa [ 158 , 159 , 160 ]. However, infections with murine Parvoviruses and Klebsiella oxytoca could not be confirmed by this method so far [ 158 , 159 ], and in the case of Staphylococcus aureus there exist contrasting results [ 159 , 160 ].…”