title: Seasonal and interseasonal dynamics of bluetongue virus infection of dairy cattle and Culicoides sonorensis midges in northern California--implications for virus overwintering in temperate zones.
abstract: Bluetongue virus (BTV) is the cause of an economically important arboviral disease of domestic and wild ruminants. The occurrence of BTV infection of livestock is distinctly seasonal in temperate regions of the world, thus we determined the dynamics of BTV infection (using BTV-specific real time reverse transcriptase polymerase chain reaction) among sentinel cattle and vector Culicoides sonorensis (C. sonorensis) midges on a dairy farm in northern California throughout both the seasonal and interseasonal (overwintering) periods of BTV activity from August 2012 until March 2014. The data confirmed widespread infection of both sentinel cattle and vector midges during the August-November period of seasonal BTV transmission, however BTV infection of parous female midges captured in traps set during daylight hours also was detected in February of both 2013 and 2014, during the interseasonal period. The finding of BTV-infected vector midges during mid-winter suggests that BTV may overwinter in northern California by infection of long-lived female C. sonorensis midges that were infected during the prior seasonal period of virus transmission, and reemerged sporadically during the overwintering period; however the data do not definitively preclude other potential mechanisms of BTV overwintering that are also discussed.
authors.affiliation: Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.
authors.forename: Christie E
authors.initials: CE
authors.lastname: Mayo
authors.affiliation: Department of Entomology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Bradley A
authors.initials: BA
authors.lastname: Mullens
authors.affiliation: Center for Vectorborne Diseases, University of California Davis, Davis, California, United States of America.
authors.forename: William K
authors.initials: WK
authors.lastname: Reisen
authors.affiliation: Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.
authors.forename: Cameron J
authors.initials: CJ
authors.lastname: Osborne
authors.affiliation: College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America.
authors.forename: E Paul J
authors.initials: EP
authors.lastname: Gibbs
authors.affiliation: Department of Health Management, Atlantic Veterinary College, Charlottetown, Prince Edward Island, Canada.
authors.forename: Ian A
authors.initials: IA
authors.lastname: Gardner
authors.affiliation: Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.
authors.forename: N James
authors.initials: NJ
authors.lastname: MacLachlan
mesh_terms: D000818:Animals; D001819:Bluetongue / Q000453:epidemiology* / Q000821:virology*; D001820:Bluetongue virus / Q000502:physiology*; D002140:California / Q000453:epidemiology; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000821:virology; D002683:Chironomidae / Q000821:virology*; D003612:Dairying; D005260:Female; D012367:RNA, Viral / Q000302:isolation & purification; D012621:Seasons
chemical_list: D012367:RNA, Viral