Replication of clinical measles virus strains in hispid cotton rats

An alternative model to nonhuman primates to study measles virus (MV) pathogenesis, to evaluate potential MV vaccines, or to screen for potential antivirals effective against this virus is highly desirable. The laboratory- adapted Edmonston strain of MV has been reported to replicate in the lungs of hispid cotton rats following intranasal inoculation, immunosuppress infected animals, and disseminate widely from the lungs, making these animals a candidate model. However, clinical MV strains have generally not been found to grow in these animals, limiting the utility and acceptance of this model. In the present studies we demonstrate reproducible replication of several clinical MV strains in hispid cotton rats. As with the Edmonston strain, leukocytes appear to be the primary target cells of these viruses following intranasal inoculation, and extrapulmonary dissemination is common. It is also demonstrated that prior MV infection or immunization of test animals with MV vaccine prevents pulmonary tract infection. These findings should make the MV-cotton rat model more acceptable.