The Arbovirus Research Program, Center for Vectorborne Diseases, University of California, Davis.

Mission.  The overall mission of the Arbovirus Research Program is to enhance our understanding of the epidemiology and ecology of the endemic and exotic mosquito-borne viruses in California and develop new tools and strategies for their surveillance and control. Research currently focuses on the endemic encephalitides, western equine encephalomyelitis and St. Louis encephalitis, and their interactions with the introduced virus, West Nile. To study virus natural history in California, study areas have been established at multiple habitats within Riverside, Los Angeles, Kern and Sacramento counties. Current sampling programs monitor mosquito abundance and viral infection rates, wild bird abundance and infection prevalence, and seroconversions in sentinel chickens. Host competence studies measure the response to vector and vertebrate hosts to viral infection. A major focus of research has been examining mechanisms that allow the persistence and effective amplification of encephalitis viruses in nature and developing tools that forecast the risk of domestic animal and human disease. Projects also evaluate the efficacy of standard and novel adult mosquito control strategies to interrupt virus transmission. Field and laboratory staff collaborate annually with the California Encephalitis Virus Surveillance Program by assisting with field sampling, diagnostics, new assay evaluation and development, surveillance data management, and web site development.

Support.  Research is supported by grants to WK Reisen from the National Institutes of Health, National Oceanographic and Atmospheric Administration, Centers for Disease Control and Prevention, NASA, and the University of California Mosquito Research Program, and support from the Coachella Valley, Greater Los Angeles County, Kern, and Sacramento-Yolo Mosquito and Vector Control Districts [MVCD].

Personnel.  Personnel are stationed at the BSL-3 containment laboratory [Ying Fang, Sandra Garcia, Maureen Dannen, Keira Simmons, Andrew Chow] and Center for Vectorborne Diseases [Bruce Eldridge, Chris Barker, Bborie Park] at UC Davis, the Arbovirus Field Station at Bakersfield [Vincent Martinez, Brian Carroll, Scott Halam, Katie Newlen, Daniel Jurich] and the Coachella Valley Mosquito and Vector Control District at Indio [Hugh Lothrop, Marc Kensington, Pat Miller], the Greater Los Angeles [Jennifer Wilson] and the Sacramento/Yolo [Veronica Armijos, Sarah Wheeler, Carrie Nielsen] MVCDs.  

Collaboration.  Surveillance diagnostics are funded through the Mosquito and Vector Control Association and the California Department of Health Services are coordinated at the BSL-3 laboratory by Dr. William K. Reisen and Ying Fang in collaboration with Dr. Aaron Brault. In collaboration with Drs. Aaron Brault, Center for Vectorborne Diseases, and Laura Kramer, NY State Health Department, molecular studies focus on virus genetic diversity and evolution in relation to persistence. Studies on mosquito pathology with Dr. William Romoser, Ohio University, explore mechanisms of virus infection. Extensive collaboration with Drs. Daniel Cayan and Michael Dettinger and Mary Tyree of the Scripps Institute of Oceanography at University of California, San Diego, are relating temporal and spatial change in mosquito abundance and virus activity measured California Encephalitis Virus Surveillance Program to climate variation at long and short term scales. Remote sensing data are included in collaboration with Forrest Melton and Brad Lobitz, NASA Ames. 

Publications.   Recently published papers are listed below.     

2004 ~ 2005 ~ 2006

2004

185.   Nelson, DM, IA Gardner, RE Chiles, UB Balasuriya, BF Eldridge, TW Scott, WK Reisen and NJ Maclachan. Prevalence of antibodies against Saint Louis encephalitis and Jamestown Canyon viruses in California horses.  Comp. Immunol. Microbiol. Inf. Dis. 27: 209-215.

186. Chiles RE, Green EN, Fang Y, Goddard L, Roth A, Reisen WK, Scott TW.  Blinded laboratory comparison of in situ enzyme immunoassay, the VecTest wicking assay and a reverse transcription-polymeras chain reaction assay to detect mosquitoes infected with West Nile and St. Louis encephalitis viruses. J Med Entomol 41: 539-544.

187. Mahmood F, Fang Y, Green EN, Clark S, Reisen WK. Evaluation of methods for studying the vector competence of Culex tarsalis for western equine encephalomyelitis virus. J Am Mosq Control Assoc 20: 277-282.

188.  Reisen WK, Chiles RE, Martinez VM, Y Fang, E Green, S Clark. Effect of dose on house finch infection with Western equine encephalomyelitis and St. Louis encephalitis viruses. J Med Entomol. 41: 978-981

189. Reisen WK, Chiles RE, Martinez VM, Green EN, Fang Y. Encephalitis virus persistence in California birds: experimental infections in mourning doves (Zenaidura macroura ). J Med Entomol 41: 462-466.

190. Mahmood,F., RE Chiles, Y Fang, CM Barker and WK Reisen. Role of nestling mourning doves and house finches as amplifying hosts of St. Louis encephalitis virus. J. Med. Entomol. 41: 965-972.

191. Reisen,W., H Lothrop, R Chiles, M Madon, C Cossen, L Woods, S Husted, V Kramer, J Edman. Invasion of California by West Nile Virus. Emerg. Inf. Dis. 10: 1369 - 1378.

192.  Mahmood F, WK Reisen, RE Chiles and Y Fang. Western equine encephalomyelitis virus infection affects the life table characteristics of Culex tarsalis (Diptera: Culicidae). J. Med. Entomol. 41: 982-985.

2005

193. Reisen, WK, Y. Fang, and V.M. Martinez. Avian host and mosquito (Diptera: Culicidae) vector competence determine the efficiency of West Nile and St. Louis encephalitis virus transmission.  J. Med. Entomol. 42: 367-375.

194. Reisen, WK, SS Wheeler, S Yamamoto, Y Fang and S Garcia. Nesting ardeid colonies are not a focus of elevated West Nile virus activity in Southern California. Vector-borne Zoonotic Dis. 5: 258-266.

195. Trevejo, RT, WK Reisen, G Yoshimura and WC Reeves. Detection of chicken antibodies to mosquito salivary gland antigens by enzyme immunoassay. J. Am. Mosq. Contr. Assoc. 21: 39-48.

196. Hull, J., A. Hull, WK Reisen, Y Fang, H Ernest. Variation in West Nile Virus Antibody Prevalence of Migrating and Wintering Hawks in Central California. Condor

2006

197. Reisen, WK, Y Fang, and VM Martinez. Effects of temperature on the transmission of West Nile virus by Culex tarsalis (Diptera: Culicidae). J. Med. Entomol. 43: 309-317

198. Reisen, WK, Y Fang, H Lothrop, V Martinez, J Wilson, P O’Connor, R Carney, B Cahoon-Young, M Shafii and AC Brault. Overwintering of West Nile virus in southern California. J. Med. Entomol. 43: 344-355.

199. Reisen, WK, CM Barker, R Carney, HD Lothrop, SS Wheeler, JL Wilson, MB Madon, R Takahashi, B Carroll, S Garcia, T Fang, M Shafii, S Ashtari, V Kramer, C Glaser, and Jean. Role of Corvids in the epidemiology of West Nile virus in Southern California. J. Med. Entomol. 43: 356-367

200. Reisen, WK, VM Martinez, Y Fang, S Garcia, S Ashtari, SS. Wheeler and BD Carroll. Role of California (Callipepla californica) and Gambel’s (Callipepla gambelii) quail in the epidemiology of western equine encephalomyelitis, St. Louis encephalitis and West Nile viruses in California, Vector-borne and Zoonotic Dis. [in press]

201. Mahmood, M., RE Chiles, Y Fang, EN Green and WK Reisen. Dose, age and genotype effect Culex tarsalis [Diptera: Culicidae] vector competence for Western equine encephalomyelitis virus. J. Amer. Mosq. Control Assoc. [in press]

202. Fang, Y and WK Reisen. Previous infection West Nile or St Louis encephalitis viruses provides cross protection during reinfection in House finches. Am. J. Trop. Med. Hyg. [in press]

203. Reisen, WK, Y Fang and VM Martinez. Vector competence of Culiseta incidens and Culex thriambus for West Nile Virus. J. Amer. Mosq. Control. Assoc. [in review]