News & Events

Arbovirus Research Program

Chris Barker, doctoral student in entomology, examines mosquito larvae. (Photo by Bill Reisen)The Center for Vectorborne Disease is a joint venture of the School of Veterinary Medicine and the College of Agricultural and Environmental Sciences at UC Davis. 

The center's Arbovirus Research Program enhances our understanding of the epidemiology and ecology of mosquitoborne viruses. Faculty members develop new tools and strategies for mosquito surveillance and control in California and around the world.

ENCEPHALITIS IN CALIFORNIA

Research within California focuses on the endemic encephalitides, that is, western equine encephalomyelitis and St. Louis encephalitis, and their interactions with the introduced West Nile virus. Drs. Aaron Brault and William Reisen of the School of Veterinary Medicine are integral players in these professional collaborations.

To study the natural history of viruses in California, researchers have established study areas at multiple habitats in Riverside, Los Angeles, Kern and Sacramento counties. Scientists collaborate closely with local agencies of the Mosquito and Vector Control Association of California as well as the Vector-Borne Disease Section and the Viral and Rickettsial Diseases Laboratory of the California Department of Public Health.

This team examines the mechanisms that allow the persistence and amplification of encephalitis viruses in nature. The scientists are developing tools that forecast the risk of animal and human disease through integration with the Environmental Assessment and Information Technology Program.

Projects also evaluate new control strategies to interrupt virus transmission. Research on West Nile virus is also conducted in the laboratory of Dr. Thomas Scott. The emphasis of these studies is on mosquito-vertebrate host and mosquito-virus interactions.

INTERNATIONAL HEALTH: DENGUE FEVER

International research programs led by Dr. Thomas Scott focus on the ecology, epidemiology and control of dengue. He investigates genetic strategies for dengue prevention in Mexico. Longitudinal cohort studies at  established field sites in Peru and Thailand examine fundamental concepts in dengue epidemiology and mosquito ecology. The ultimate goal is to improve tools and strategies for mosquito control and disease prevention. Of particularly interest are the impacts of heterogeneities in patterns of human infection (i.e., spatial, temporal, age, or sex differences) on the force of virus transmission and how that information can be applied in practical ways, for example, surveillance, vector control and vaccine delivery.

MONITORING AND DIAGNOSIS

Surveillance activities and reference diagnostics funded through the Mosquito and Vector Control Association and the California Department of Public Health are coordinated at the BSL-3 laboratory by Drs. Reisen and Brault. Team members test mosquito pools and dead bird tissues for the California Mosquitoborne Encephalitis Virus Surveillance Program. This team also performs avian serology for the Wildlife Health Center and tests avian samples for the University of Tulsa.

Selected Publications:

  • 2007
    • Armijos, V., S. S. Wheeler, Y. Fang, S. Garcia, S. A. Wright, K. Kelley, and W. K. Reisen. 2007. Are Ardeid colonies nesting over dry land a source of West Nile virus amplification? Proc. Mosq. Vector Control Assoc. Calif. 75: 7-8.
    • Barker, C. M., W. K. Reisen, B. F. Eldridge, W. O. Johnson, and J. Gill. 2007. Population Dynamics of Culex tarsalis in the Sacramento Valley of California. Proc. Mosq. Vector Control Assoc. Calif. 75
    • Boyce, W. M., S. P. Lawler, J. M. Schultz, S. J. McCauley, L. S. Kimsey, M. K. Niemela, C. F. Nielsen, and W. K. Reisen. 2007. Nontarget effects of the mosquito adulticide Pyrethrin applied aerially during a West Nile virus outbreak in an urban California environment. J Am Mosq. Control Assoc. 23: 335-339.
    • Brault, A. C., C. Y. Huang, S. A. Langevin, R. M. Kinney, R. A. Bowen, W. N. Ramey, N. A. Panella, E. C. Holmes, A. M. Powers, and B. R. Miller. 2007. A single positively selected West Nile viral mutation confers increased virogenesis in American crows. Nat. Genet. 39: 1162-1166.
    • Carroll, B. D., R. M. Takahashi, and W. K. Reisen. 2007. West Nile Virus Activity in Kern County During 2006. Proc. Mosq. Vector Control Assoc. Calif. 75: 17-22.
    • Eldridge, B. F., and B. Park. 2007. CalSurv: one-stop shopping for Vectorborne Disease Surveillance. Proc. Calif. Mosq. Control Assoc. 75: 43-44.
    • Lothrop, H. D., H. Huazhang, B. Lothrop, S. Gee, D. E. Gomsi, and W. K. Reisen. 2007. Deposition of pyrethrins and piperonyl butoxide following aerial ULV applications in the Coachella Valley, California. J. Am. Mosq. Control Assoc. 23: 213-219.
    • Lothrop, H. D., B. Lothrop, M. Palmer, S. S. Wheeler, A. Gutierrez, P. Miller, D. E. Gomsi, and W. K. Reisen. 2007. Evaluation of Pyrenone aerial ULV applications for adult Culex tarsalis control in the desert environments of the Coachella Valley of California. J. Am Mosq. Control Assoc. 23: 405-419.
    • Lothrop, H. D., B. Lothrop, W. K. Reisen, and D. E. Gomsi. 2007. Did early intervention at North Shore in the Coachella Valley interrupt West Nile virus amplification? Proc. Mosq. Vector Control Assoc. Calif. 75: 9-13.
    • Lothrop, H. D., B. Lothrop, M. Palmer, S. S. Wheeler, A. Gutierrez, D. E. Gomsi, and W. K. Reisen. 2007. Efficacy of Pyrethrin and Permethrin ground ULV applications for adult Culex control in rural and urban desert environments of the Coachella Valley of California. J. Am Mosq. Control Assoc. 20: 190-207.
    • Nielsen, C. F., and W. K. Reisen. 2007. Dead birds increase the risk of West Nile Virus infection in Culex mosquitoes (Diptera: Culicidae) in Domestic Landscapes. J. Med. Entomol. 44: 1007-1013.
    • O'Connor, P., J. L. Wilson, J. Spoehel, S. Kluh, H. Morales, and M. B. Madon. 2007. West Nile virus Foci in Greater Los Angeles County Vector Control District, 2003 - 2006. Proc. Mosq. Vector Control Assoc. Calif. 75: 14-16.
    • Padgett, K. A., W. K. Reisen, N. Kahl-Purcell, Y. Fang, B. Cahoon-Young, R. Carney, N. Anderson, L. Zucca, L. Woods, S. Husted, and V. L. Kramer. 2007. West Nile virus infection in tree squirrels (Rodentia: Scuridae) in California, 2004-2005. Am J Trop. Med. Hyg. 76: 810-813.
    • Reisen, W., and A. C. Brault. 2007. West Nile virus in North America: perspectives on epidemiology and intervention. Pest Manag. Sci. 63: 641-646.
    • Reisen, W. K., A. C. Brault, V. M. Martinez, Y. Fang, K. Simmons, S. Garcia, E. Omi-Olsen, and R. S. Lane. 2007. Ability of transstadially infected Ixodes pacificus (Acari: Ixodidae) to transmit West Nile virus to song sparrows or western fence lizards. J Med. Entomol. 44: 320-327.
    • Reisen, W. K., and Y. Fang. 2007. Does feeding on infected mosquitoes (Diptera: Culicidae) enhance the role of song sparrows in the transmission of arboviruses in California? J Med. Entomol. 44: 316-319.
    • Reisen, W. K., Y. Fang, and V. Martinez. 2007. Is nonviremic transmission of West Nile virus by Culex mosquitoes (Diptera: Culicidae) nonviremic? J Med. Entomol. 44: 299-302.
    • Reisen, W. K., and D. C. Hahn. 2007. Comparison of immune responses of brown-headed cowbird and related blackbirds to West Nile and other mosquito-borne encephalitis viruses. J Wildl. Dis. 43: 439-449.
    • Wheeler, S. S., M. V. Armijos, S. Garcia, Y. Fang, and W. K. Reisen. 2007. Migratory birds and the spread of encephalitis viruses in California: 10 years of data from the Coachella Valley. Proc. Mosq. Vector Control Assoc. Calif. 75: 4-6.
  • 2008
    • Lothrop, H. D., B. Lothrop, D. E. Gomsi, and W. K. Reisen. 2008. Intensive early season adulticide applications decrease arbovirus transmission throughout the Coachella Valley, Riverside County, California. Vector Borne and Zoonotic Dis. [in press]
    • McAbee, R. D., E. N. Green, J. Holeman, J. Christiansen, N. Frye, K. Dealey, F. S. Mulligan, III, A. C. Brault, and A. J. Cornel. 2008. Identification of Culex pipiens Complex Mosquitoes in a Hybrid Zone of West Nile Virus Transmission in Fresno County, California. Am J Trop. Med. Hyg. 78: 303-310.
    • Nielsen, C. F., W. K. Reisen, V. Armijos, N. J. MacLachlan, and T. W. Scott. 2008. High subclinical West Nile virus incidence among unvaccinated horses in Northern California associated with low vector abundance. Am. J. Trop. Med. Hyg. 78: 45-52.
    • Nielsen, C. F., V. Armijos, S. S. Wheeler, T. E. Carpenter, K. Kelley, W. M. Boyce, D. A. Brown, and W. K. Reisen. 2008. Risk factors associated with the 2006 West Nile virus outbreak in Davis, a residential community in Northern California. Am J. Trop. Med. Hyg. 78: 53-62.
    • Patiris, P. J., L. Oceguera III, G. W. Peck, R. E. Chiles, W. K. Reisen, and C. V. Hanson. 2008. Serological diagnosis of West Nile and St. Louis encephalitis virus infections in domestic chickens. Am J Trop. Med. Hyg. [in press]
    • Reisen, W. K. and C. M. Barker. 2008. Use of climate variation in vectorborne disease decision support systems. Global Climate Change and Extreme Weather Events: Understanding the Potential Contributions to the Emergence, Reemergence and Spread of Infectious Disease Washington, DC. Institute of Medicine.
    • Reisen, W. K., H. D. Lothrop, S. S. Wheeler, M. Kensington, A. Gutierrez, Y. Fang, S. Garcia, and B. Lothrop. 2008. Persistent West Nile virus transmission and the displacement St Louis encephalitis virus in southeastern California, 2003 - 2006. J. Med. Entomol. [in press]
    • Reisen, W. K., D. Cayan, M. Tyree, C. M. Barker, B. F. Eldridge, and M. Dettinger. 2008. Impact of climate variation on mosquito abundance in California. J. Soc. Vector Ecol. in press
    • Reisen, W. K., Y. Fang, and A. C. Brault. 2008. Limited temporal variation in mosquito (Diptera: Culicidae) and avian host competence for western equine encephalomyelitis virus (Togaviridae: Alphavirus). Am. J. Trop. Med. Hyg. submitted
    • Wheeler, S. S., C. M. Barker, M. V. Armijos, B. D. Carroll, S. R. Husted, and W. K. Reisen. 2008. Impact of West Nile virus on California birds: who lives and who dies. J. Avian Biol. [in review].

Arbovirus research is supported by grants from the National Institutes of Health, Bill & Melinda Gates Foundation, National Oceanographic and Atmospheric Administration, Centers for Disease Control and Prevention, National Aeronautics and Space Administration, University of California Mosquito Research Program, and the Coachella Valley, Greater Los Angeles County, Kern, and Sacramento-Yolo Mosquito and Vector Control Districts.