The Implications of Rat Polyomavirus 2

RPyV2 can cause disease and mortality in immunodeficient animals. Further population surveys found antibodies to this novel virus in 32% of immunocompetent rats used in biomedical research. We’ve developed and validated both serologic and molecular diagnostic assays for RPyV2 as stand alone tests that can also be added to any profile.

Research Summary


Rats presented with a history of low fecundity and signs of anorexia, emaciation, hunched posture and dyspnea.


Histological examination
demonstrated viral inclusions in multiple tissues, most notably, within epithelial cells of the respiratory tract and salivary glands.

Deep sequencing identified a novel virus of the family Polyomaviridae, provisionally named Rattus norvegicus polyomavirus 2 (RPyV2).


RPyV2 is an epitheliotropic polyomavirus

Virus is shed primarily in respiratory and salivary secretions. Shedding is prolonged in immunodeficient rats and transient in immunocompetent rats.

Virus transmission occurs by direct contact. Fecal-oral and sexual transmission may also occur.

Based on client samples received by our lab, prevalence of RPyV2 infection in rat research colonies is 32%.

Detection of RPyV2 infection can be made by serology testing for immunocompetent rats and fecal PCR for immunodeficient rats.


Disease Expression

• Immunodeficient rats with a history of low fecundity and associated mortality of dams and pups.

• Clinical signs included emaciation, hunched posture and dyspnea.

• Evaluation of tissues revealed severe degeneration of the salivary glands; the exorbital lacrimal glands and  Harderian glands; viral infection of the epithelium of the respiratory and reproductive tracts.











RPyV2 is an epitheliotropic polyomavirus.

RPyV2 transmission may be through oral, nasal, and respiratory secretions with primary replication in the
epithelial cells of glandular and respiratory tissues prior to systemic spread.

RPyV2 shedding is prolonged in immunodeficient rats, transient in immunocompetent rats.

Estimated to be 32% in immunocompetent animals.

RPyV2 infection can be detected by serologic testing for immunocompetent rats and by fecal PCR for immunodeficient rats.


A Case for Innovation

The IDEXX BioAnalytics scientific team collaborates on discoveries or
characterizations of novel viruses such as in this case: 
Clients at a university RPOLY-IPad-Sales-Presentation-f-6-6-1.pngturned to IDEXX BioAnalytics for our expertise—they saw an increase in signs of disease and death among their females and pups in their SCID rat colony and needed to know, “why?”

Our BioAnalytics departments including Necropsy, PCR, Serology, Pathology and vivarium staff combined their expertise to dig deeper—even after initial test results came back negative.

Further investigation conclusively revealed a novel virus unrelated to those known to infect rats, mice, or other laboratory animals.

Serologic and molecular assays for the novel Rat polyomavirus 2 (RPyV2) were developed and validated by Dr. Bob Livingston and Dr. Matt Myles respectively.

When you partner with IDEXX BioAnalytics, you will always have access to the latest, cutting edge information and diagnostics


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