Reemergence of St. Louis Encephalitis Virus, California, 2015

Abstract

St. Louis encephalitis virus infection was detected in summer 2015 in southern California after an 11-year absence, concomitant with an Arizona outbreak. Sequence comparisons showed close identity of California and Arizona isolates with 2005 Argentine isolates, suggesting introduction from South America and underscoring the value of continued arbovirus surveillance.

Keywords: California; St. Louis encephalitis virus; arbovirus; arbovirus sequencing; arbovirus surveillance; bird; emerging; flavivirus; global viral spread; human pathogen; mosquito; mosquito pool testing; mosquitoborne virus; sentinel bird; vector-borne infections; viral phylogenetics; viruses.