Combining genomics and epidemiology to track mumps virus transmission in the United States.

Unusually large outbreaks of mumps across the United States in 2016 and 2017 raised questions about the extent of mumps circulation and the relationship between these and prior outbreaks. We paired epidemiological data from public health investigations with analysis of mumps virus whole genome sequences from 201 infected individuals, focusing on Massachusetts university communities. Our analysis suggests continuous, undetected circulation of mumps locally and nationally, including multiple independent introductions into Massachusetts and into individual communities. Despite the presence of these multiple mumps virus lineages, the genomic data show that one lineage has dominated in the US since at least 2006. Widespread transmission was surprising given high vaccination rates, but we found no genetic evidence that variants arising during this outbreak contributed to vaccine escape. Viral genomic data allowed us to reconstruct mumps transmission links not evident from epidemiological data or standard single-gene surveillance efforts and also revealed connections between apparently unrelated mumps outbreaks

Comparison of L proteins of vaccine and wild-type measles viruses.

The nucleotide sequences of the large (L) genes of ten measles virus (MV) strains were determined. These strains included the Moraten and Rubeovax vaccine strains and their Edmonston wild-type (wt) progenitor, two additional vaccine strains and five genotypically divergent wt isolates. The nucleotide and predicted amino acid sequences were compared with six previously sequenced L genes and the number and location of variable amino acid positions were characterized. The recent wt isolates demonstrated the greatest amount of variability found to date in the highly conserved L protein. Three full-length wt L proteins were expressed in mammalian cells and their ability to form a complex with the MV phosphoprotein was demonstrated. While no set of amino acid substitutions associated consistently with wt or vaccine strains was identified, these data will provide a basis for the analysis of the activity of L proteins from vaccine and wt viruses in a functional assay

Measles virus nucleocapsid protein protects rats from encephalitis

Lewis rats immunized with recombinant vaccinia virus expressing the nucleocapsid (N) protein of measles virus were protected from encephalitis when subsequently challenged by intracerebral infection with neurotropic measles virus. Immunized rats revealed polyvalent antibodies to the N protein of measles virus in the absence of any neutralizing antibodies as well as an N protein-specific proliferative lymphocyte response. Depletion of CD8+ T lymphocytes did not abrogate the protective potential of the N protein-specific cell-mediated immune response in rats, while protection could be adoptively transferred with N protein-specific CD4+ T lymphocytes. These results indicate that a CD4+ cell-mediated immune response specific for the N protein of measles virus is sufficient to control measles virus infections of the central nervous system.</jats:p