Emergence of a new lineage of Cache Valley virus (Bunyaviridae: Orthobunyavirus) in the Northeastern United States

Am J Trop Med Hyg. 2015 Jul;93(1):11-7. doi: 10.4269/ajtmh.15-0132. Epub 2015 May 11.


Cache Valley virus (CVV; Family Bunyavidae, Genus Orthobunyavirus) is a mosquito-borne zoonosis that frequently infects humans and livestock in North and Central America. In the northeastern United States, CVV transmission is unpredictable from year-to-year and may derive from the periodic extinction and reintroduction of new virus strains into this region. To evaluate this possibility, we sequenced and analyzed numerous CVV isolates sampled in Connecticut during an 18-year period to determine how the virus population may change over time. Phylogenetic analyses showed the establishment of a new viral lineage during 2010 that became dominant by 2014 and appears to have originated from southern Mexico. CVV strains from Connecticut also grouped into numerous sub-clades within each lineage that included viruses from other U.S. states and Canada. We did not observe the development and stable persistence of local viral clades in Connecticut, which may reflect the episodic pattern of CVV transmission. Together, our data support the emergence of a new lineage of CVV in the northeastern United States and suggest extensive dispersal of viral strains in North America.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bunyamwera virus / genetics*
  • Bunyamwera virus / isolation & purification
  • Connecticut
  • Culicidae / virology*
  • Insect Vectors / virology*
  • Orthobunyavirus
  • Phylogeny
  • RNA, Viral / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Analysis, RNA


  • RNA, Viral