Theilers disease PCR test

Theiler’s murine encephalomyelitis virus (TMEV) is a single-stranded RNA picornavirus that persistently infects the murine central nervous system. The virus has recently been reclassified into the cardiovirus group. Mice are the natural host of this virus. In the wild it produces a gastrointestinal infection that may be complicated by concomitant infection of the nervous system.

There are two main groups of TMEV. One includes the GDVII and FA viruses, which produce an acute fulminant encephalomyelitis, which is fatal in about a week. The other, called Theiler’s original group, includes the DA, BeAn, and WW viruses. These produce a chronic persistent central nervous system infection, accompanied by inflammatory demyelinating lesions of the spinal cord with features very similar to those of demyelinating plaques seen in human multiple sclerosis. The demyelination induced by TMEV infection is mediated by the immune system rather than as a consequence of viral infection of oligodendrocytes, the myelin forming cells.

A classic study (Theiler, 1937) showed that mice infected with the virus may not show prominent symptoms and become carriers of the virus. The virus can be transmitted easily through soiled bedding. Infected immunocompetent mice may shed TMEV in the feces for as long as 53 days; the duration of shedding by immunodeficient mice has not been reported but is likely longer (Clifford and Watson, 2008).

Serological detection of the virus is inadequate, especially in nude or immunocompromised mice. Furthermore, neonatal mice infected with the virus may not be readily identified due to residual maternal antibodies. Molecular detection by PCR can overcome these problems and is highly sensitive and specific for TMEV.

Utilities:

Help confirm the disease causing agent
Shorten the time required to confirm a clinical diagnosis of TMEV
Help ensure that rodent facilities are free of TMEV
Early prevention of spread of this virus among a rodent facility
Minimize personnel exposure to this virus
Safety monitoring of biological products that derive from mice

References:
Theiler, M. (1937) Spontaneous encephalomyelitis of mice, a new virus disease, J. Exp. Med. 65: 705–719.

Clifford, C.B. and Watson, J. (2008) Old Enemies, Still with Us After All These Years, ILAR Journal Vol. 49, No. 3: 291-301.

Specimen requirements: Fecal pellet, or 0.2 ml whole blood in EDTA (purple top) tube, or 0.2 ml CSF, or 0.2 ml fresh or frozen tissue, or 0.2 ml cell culture.

Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative reverse transcription coupled real time polymerase chain reaction

Normal range: Nondetected