The Center for Vectorborne Diseases has four major programs.
Arbovirus Research Program
Mission: The mission of the Arbovirus Research Program is to
enhance our understanding of the epidemiology and ecology of
mosquitoborne viruses and develop new tools and strategies for their
surveillance and control.
Research within California currently led by Drs. AC Brault and WK
Reisen 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, we have established study areas at multiple habitats within
Riverside, Los Angeles, Kern and Sacramento counties and 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.
A major focus is the examination of
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 through integration with the
Environmental Assessment and Information Technology Program. Projects
also evaluate the efficacy of standard and novel adult mosquito control
strategies to interrupt virus transmission. Research on West Nile virus
is also conducted in the laboratory of Dr. TW Scott. The emphasis of
these studies is on mosquito-vertebrate host and mosquito-virus
International research programs led by Dr. TW Scott focus on the
ecology, epidemiology and control of dengue. Genetic strategies for
dengue prevention are investigated in Mexico. Longitudinal cohort
studies at well established field sites in Peru and Thailand examine
fundamental concepts in dengue epidemiology and mosquito ecology, with
the ultimate goal of improving 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, sex, etc.) on the force of virus transmission
and how that kind of information can be captured and applied in
operationally amenable ways (i.e., surveillance, vector control,
vaccine delivery, etc.).
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 and supervised by Y Fang and M Dannen. Current diagnostics
test mosquito pools and dead bird tissues for the California
Mosquitoborne Encephalitis Virus Surveillance Program, avian serology
for the Wildlife Health Center, avian and samples for Tulsa University.
Support: 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.
- Armijos, V., A. C. Brault, S. S. Wheeler, Y. Fang, S. Langevin, N. Wanichaya, S. A. Wright, and W. K. Reisen. 2006. Preliminary findings of a Fort-Morgan-like alphavirus from Cliff Swallow bugs [Oeciacus vicarius (Hemiptera:Cimicidae)] in Sacramento County. Proc. Mosq. Vector Control Assoc. Calif. 74: 82-83.
- Deardorff, E., J. Estrada-Franco, A. C. Brault, R. Navarro-Lopez, A. Campomanes-Cortes, P. Paz-Ramirez, M. Solis-Hernandez, W. N. Ramey, C. T. Davis, D. W. Beasley, R. B. Tesh, A. D. Barrett, and S. C. Weaver. 2006. Introductions of West Nile virus strains to Mexico. Emerg. Infect. Dis. 12: 314-318.
- Fang, Y., and W. K. Reisen. 2006. Previous infection with West Nile or St. Louis encephalitis viruses provides cross protection during reinfection in house finches. Am J Trop. Med. Hyg. 75: 480-485.
- Hull, J., A. Hull, W. K. Reisen, Y. Fang, and H. Ernst. 2006. Variation in West Nile Virus Antibody Prevalence in Free-ranging California Raptors. The Condor 108: 435-439.
- Kinney, R. M., C. Y. Huang, M. C. Whiteman, R. A. Bowen, S. A. Langevin, B. R. Miller, and A. C. Brault. 2006. Avian virulence and thermostable replication of the North American strain of West Nile virus. J Gen. Virol. 87: 3611-3622.
- Mahmood, F., R. E. Chiles, Y. Fang, E. N. Green, and W. K. Reisen. 2006. Effects of time after infection, mosquito genotype, and infectious viral dose on the dynamics of Culex tarsalis vector competence for western equine encephalomyelitis virus. J. Am. Mosq. Control Assoc. 22: 272-281.
- Padgett, K. A., B. Cahoon-Young, R. Carney, L. Woods, D. Read, S. Husted, and V. Kramer. 2006. Field and laboratory evaluation of diagnostic assays for detecting West Nile virus in oropharyngeal swabs from California wild birds. Vector Borne Zoonotic Dis. 6: 183-191.
- Reisen, W. K., V. M. Martinez, Y. Fang, S. Garcia, S. Ashtari, S. S. Wheeler, and B. D. Carroll. 2006. Role of California (Callipepla californica) and Gambel's (Callipepla gambelii) quail in the ecology of mosquito-borne encephalitis viruses in California, USA. Vector Borne Zoonotic Dis. 6: 248-260.
- Reisen, W. K., C. M. Barker, R. Carney, H. D. Lothrop, S. S. Wheeler, J. L. Wilson, M. B. Madon, R. Takahashi, B. Carroll, S. Garcia, Y. Fang, M. Shafii, N. Kahl, S. Ashtari, V. Kramer, C. Glaser, and C. Jean. 2006. Role of corvids in epidemiology of West Nile virus in southern California. J Med. Entomol. 43: 356-367.
- Reisen, W. K., Y. Fang, and V. M. Martinez. 2006. Effects of temperature on the transmission of West Nile virus by Culex tarsalis (Diptera: Culicidae). J Med. Entomol. 43: 309-317.
- Wilson, J. L., W. K. Reisen, and M. B. Madon. 2006. Three Years of West Nile virus in Greater Los Angeles County. Proc. Mosq. Vector Control Assoc. Calif. 74: 9-11.
- 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.
- 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].
Environmental Assessment and Information Technology Program
Mission: The mission of the Environmental
Assessment and Information Technology Program (EAIT) is to develop
modern methods of management of vectorborne disease research and
surveillance data, to develop predictive models based on these data,
and to facilitate sharing of research and surveillance data among
California agencies cooperating in the prevention and control of
vectorborne diseases in California. Included in this mission is the
development of public and collaborative websites providing interactive
information on vectorborne diseases in California.
and development activities relating to EAIT are supported by grants to
Dr. William Reisen and Dr. Chris Barker from the National Institutes of Health, the National
Oceanic and Atmospheric Administration, the Centers for Disease
Control and Prevention, the National Aeronautics and Space
Administration, the University of California Mosquito Research Program,
and the Coachella Valley, Greater Los Angeles County, Kern, and
Sacramento-Yolo Mosquito and Vector Control Districts.
are stationed on Old Davis Road south of the main
UCD campus. EAIT is under the direction of Dr. Bruce Eldridge. Bborie Park serves as Programmer/Network administrator. He is the author of the California Vectorborne Surveillance Gateway. Dr. Chris Barker
is an Assistant Research Epidemiologist who is developing models to predict mosquito
abundance and mosquitoborne viral activity in California based on
climatic, edaphic, and land-use factors. Dr. William Reisen coordinates activities of the program with those of the Arbovirus Research Program that he directs.
There is extensive collaboration with Drs. Daniel Cayan and Michael
Dettinger and Mary Tyree of the Scripps Institution of Oceanography at
University of California, San Diego. These scientists are relating
temporal and spatial changes in mosquito abundance and virus activity
to long and short term climatic variation. Remotely sensed data are
included in collaboration with Forrest Melton and Dr. Brad Lobitz of
NASA Ames Research Center. Mathematical models of West Nile virus are being developed in collaboration with Dr. David Hartley and Dr. Tianchan Niu of Georgetown University and Dr. Arnaud Le Menach of the Health Protection Agency, London.
- Development of web-based interactive mapping for visualization of surveillance data.
- Development of the California Vectorborne Disease Gateway, a complete mosquitoborne virus surveillance management system.
- Development of the CalSurv vectorborne disease website based on Drupal, a system for multi-author content management.
Barker CM, Reisen WK, Kramer VL. 2003. California state Mosquito-borne
Virus Surveillance and Response Plan: a retrospective evaluation using
conditional simulations. Am J Trop Med Hyg 68: 508-518.
Barker CM, Reisen WK, Kramer VL, Husted S, Hom A, Eldridge BF. 2004. An
improved system for objective statewide trap stratification based on
human population density. Proc Mosq Vector Control Assoc Calif 72:
Barker CM, Reisen WK, Eldridge BF. 2005. Factors affecting the
probability of mosquito-borne virus activity in California vector
control districts, 1982-2003. Proc Mosq Vector Contr Assoc Calif
Marcus L, Eldridge BF, Lewis S, Barker C, Nastoff T, Crawford C,
Richman L, Westmoreland R, Husted S, Kramer V. 2005. The development of
the California Department of Public Health West Nile virus website (westnile.ca.gov)
as a tool for local agencies, information distribution to the public,
passive surveillance, and public educators. Proc Mosq Vector Contr
Assoc Calif 73:89.
- Eldridge BF, Barker CM, Reisen WK, Baylis E,
Hom A. 2006. Use of sentinel chickens in California for arbovirus
surveillance, 1962-2005: data aggregation and analysis. Proc Mosq
Vector Control Assoc Calif 74: 55-58.
Eldridge, BF, Park, BK. 2007. CalSurv: One-stop Shopping for
Vectorborne Disease Surveillance. Proc Mosq Vector Contr Assoc Calif
75: [in press].
Barker CM, Reisen WK, Eldridge BF, Johnson WO, Gill J. 2007. Dynamics
of Culex tarsalis in the Sacramento Valley of California. Proc Mosq
Vector Contr Assoc Calif 75: [in press].
Tickborne Disease Research Program
Ticks rank with mosquitoes as the most important arthropod vectors
of disease to humans and animals worldwide. In the western US,
important tickborne diseases include Lyme disease and granulocytic
anaplasmosis (caused by Anaplasma phagocytophilum) of humans, anaplasmosis (caused by A. marginale) and
epizootic bovine abortion of cattle, ehrlichiosis of dogs, and
anaplasmosis of horses. Internationally, ticks vector heartwater and
babesiosis in cattle, tickborne rickettsiosis and tickborne
encephalitis in humans, and other devastating problems that result in
death, suffering and huge economic losses. Ticks may induce tick
paralysis, directly cause blood-loss anemia, develop multi-drug
resistance to the chemicals used to kill and control them, and be
responsible for enormous eradication and control programs.
are multiple projects at UC Davis in tickborne disease, depending on
the interests and skills of the lead investigators or graduate
students. Most projects focus on ecology and epidemiology of tickborne
disease. Most ticks feed over the course of their lives on two or more
different host species, so there are opportunities for interesting and
complex ecologies. Studying such ecological problems requires expertise
in field biology, theory, mammalogy, veterinary medicine, tick biology,
bacteriology, and other disciplines. We work through local and
international collaborations to acquire the needed expertise, including
with Drs. Wuchun Cao and Jing He at the Beijing Institute for
Microbiology and Epidemiology in the People's Republic of China, Dr.
Bob Lane in the Division of Insect Biology at UC Berkeley, Dr. Rick
Brown in the Department of Wildlife at Humboldt State University, Dr.
Patrick Foley in the Department of Biological Sciences at California
State University Sacramento, Dr. Steve Dumler at Johns Hopkins
University, Dr. Joon Seuk Chae at Chonbuk National University in South
Korea, and others.
Current ongoing projects include forest change and the emergence of disease transmitted by Ixodes ricinus group
hard ticks in northern California and northeastern China (Foley lead
investigator), spread and maintenance of EBA in cattle California and
soft ticks (Teglas), modeling the enzootic maintenance of granulocytic
anaplasmosis in California wildlife (J. Foley and P. Foley),
understanding high anaplasmosis and Lyme-risk regions of far northern
California through wildlife and tick studies (Brown and Foley),
comparative habitat analysis for hard-tick borne disease in the western
US (Nieto), and developing an active surveillance program for exotic
ticks of cattle in California (Foley).
Vector Genetics Laboratory
The overall research focus of the lab is the population and molecular genetics of insect vectors of human disease. We have developed a program that pursues knowledge that may be applied to the control of vectorborne diseases but at the same time addresses critical issues in basic evolutionary genetics. An additional goal is the application of cutting edge molecular biological methods to problems at the level of populations. Research efforts involve both field and laboratory based research. Over the past several years we have conducted extensive fieldwork in Mali, Cameroon, Brazil, Costa Rica and Nicaragua. The Laboratory of Vector Genetics is directed by UC Davis medical entomologist Gregory Lanzaro, a professor in the Department of Pathology, MIcrobiology and Immunology (PMI) of the School of Veterinary Medicine, University of California, Davis.
Visit the Vector Genetics Laboratory website.