Mouse parvoviruses (MPVs) are small, single-stranded, 5 kb DNA viruses that are subclinical and endemic in many laboratory mouse colonies. MPVs cause more distinctive deleterious effects in immune-compromised or genetically-engineered mice than immuno-competent mice. At the University of Louisville (U of L), there was an unexpected increase of MPV sero-positivity for MPV infections in mouse colonies between January 2006 and February 2007, resulting in strategic husbandry changes aimed at controlling MPV spread throughout the animal facility. To investigate these MPVs, VP2 genes of seven MPVs were cloned and sequenced from eight documented incidences by PCR technology. The mutations in these VP2 genes were compared to those found at the Genbank database (NCBI; http://www.ncbi.nlm.nih.gov) and an intra-institutional phylogenetic tree for MPV infections at U of L was constructed. We discovered that the seven MPV isolates were different from those in Genbank and were not identical to each other. These MPVs were designated MPV-UL1 to 7; none of them were minute virus of mice (MVMs). Four isolates could be classified as MPV1, one was classified as MPV2, and two were defined as novel types with less than 96% and 94% homology with existing MPV types. Considering that all seven isolates had mutations in their VP2 genes and no mutations were observed in VP2 genes of MPV during a four-month time period of incubation, we concluded that all seven MPVs isolated at U of L between 2006 and 2007 probably originated from different sources. Serological survey for MPV infections verified that each MPV outbreak was controlled without further contamination within the institution.
Keywords: A; EDIM; ELISA; Epidemiology; F; HEPA; HaPV; IACUC; IBC; L; LCMV; MCMV; MHV; MOPV; MPV; MTV; MVM; Mouse cytomegalovirus; Mouse parvovirus; N; ORFs; PCR; PVM; Phylogenetic tree; RADIL; RRF; S; SPF mice; T; U of L; U of L isolates of parvovirus; UL; University of Louisville; V; VLPs; VP; VP2 sequence; aa; alanine; amino acid; asparagin; enzyme-linked immunosorbent assay; epizootic diarrhea of infant mice; hamster parvovirus; high-efficiency particulate air; institutional animal care and use committee; institutional biosafety committee; leucine; lymphocytic choriomeningitis virus; minute virus of mice; mouse hepatitis virus; mouse mammary tumor virus; mouse orphan parvovirus; mouse parvovirus; mouse specific pathogen free mice; open reading frames; phenylalanine; pneumonia virus of mice; polymerase chain reaction; research animal diagnostic laboratory; research resources facilities; serine; threonine; valine; virus particle; virus-like particles.
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