ABSTRACT
Reovirus infections are typically subclinical in weaned mice, and are best detected using serologic tests. After exposure to the soiled bedding of some mice obtained from various sources, numerous sentinel mice tested reovirus seropositive by use of indirect immunofluorescence assays (IIFA) in our institution. A major commercial rodent pathogen testing laboratory verified our IIFA results, but since the same samples were reovirus seronegative using their "more specific" enzyme-linked immunosorbent assay (ELISA), the IIFA results were reported as "false positives." As past in-house observations suggested transmission of the virus to sentinel and other animals, we sought to determine whether the IIFA results were always "false positives." An opportunity to test this notion arose after receipt of reovirus IIFA-positive transgenic mice from an academic source. Using reverse transcriptase-polymerase chain reaction (RT-PCR) assays, the presence of reovirus RNA was detected in fecal specimens taken from some sentinel animals that subsequently seroconverted from IIFA-negative to IIFA-positive for reovirus. The virus could not be isolated by use of tissue culturing methods. Nucleotide sequence analysis established the presence of unique reovirus sequences. These results indicate that contemporary reovirus infections may not be detected by use of some serologic tests, and that RT-PCR analysis may be useful for confirmation of active reovirus infection in certain situations.
