The broad objectives of this research are to expand ongoing studies of the mechanisms and routes by which the Lyme disease (LD) spirochete, Borrelia burgdorferi (Bb), is maintained and distributed among wildlife and humans in a highly endemic area of the Far West; to further assess environmental factors that may place people at risk of acquiring Bb-infection or LD; and to determine the antiquity of Bb-infection in this region. Human risk of exposure to vector ticks along trails and in picnic areas will be compared with an ecological index of risk in several heavily-used recreational areas in northern California. Tick abundance will be quantified by flagging vegetation and by enumerating ticks that adhere to the clothing of a walker simulating a hiker. Infection rates will be determined by testing ticks with standard microbiological procedures. A follow-up seroepidemiologic study of a high-risk community (HRC) will be undertaken to discover if the presence of tick- or insect-specific IgG can be correlated with seroprevalence to Bb and self-reported exposure histories to arthropod bites; 3 assays will be performed including ELISA, SDS-PAGE and immunoblotting. Peridomestic exposure to Bb in the HRC will be evaluated by comparing the abundance of, and spirochetal infection rates in, vector ticks and anthropophilic bloodsucking flies collected around the homes of LD victims vs. non-victims. The ability of 2 species of hard ticks (Ixodes spp.) and the western cone-nose bug to acquire, maintain, and transmit Bb will also be determined using rodents as experimental hosts. Further, the concept that each of the 3 species of North American relapsing fever spirochetes is confined to one species of soft tick will be reevaluated because of geographic overlap with Bb. Fresh isolates of all 3 Borrelia spp. will be characterized molecularly to determine if they are indeed specifically distinct, and the vector competence of each of their soft tick vectors (Ornithodoros spp.) for all 3 spirochetes and for Bb will be studied. Field and laboratory studies will be carried out to fill-in some basic gaps in knowledge concerning the life histories of 2 important western vectors of Bb, Ixodes pacificus and Ixodes neotomae, especially the former. Information gleaned from these studies will be used to model the population dynamics of Ixodes pacificus. Finally, 3 kinds of archival museum specimens (ticks, woodrat skins, Native American skeletal remains) will be assayed for Bb-nucleic acid with the polymerase chain reaction to determine the antiquity of LD in this region.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
2R01AI022501-09
Application #
3133635
Study Section
Epidemiology and Disease Control Subcommittee 2 (EDC)
Project Start
1985-09-01
Project End
1998-08-31
Budget Start
1993-09-01
Budget End
1994-08-31
Support Year
9
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of California Berkeley
Department
Type
Schools of Earth Sciences/Natur
DUNS #
094878337
City
Berkeley
State
CA
Country
United States
Zip Code
94704
Eisen, Rebecca J; Clark, Rebecca J; Monaghan, Andrew J et al. (2017) Host-Seeking Phenology of Ixodes pacificus (Acari: Ixodidae) Nymphs in Northwestern California in Relation to Calendar Week, Woodland Type, and Weather Conditions. J Med Entomol 54:125-131
Foley, Janet E; Hasty, Jeomhee M; Lane, Robert S (2016) Diversity of rickettsial pathogens in Columbian black-tailed deer and their associated keds (Diptera: Hippoboscidae) and ticks (Acari: Ixodidae). J Vector Ecol 41:41-7
Eisen, Rebecca J; Clark, Rebecca J; Monaghan, Andrew J et al. (2016) Host-Seeking Phenology of Ixodes pacificus (Acari: Ixodidae) Nymphs in Northwestern California in Relation to Calendar Week, Woodland Type, and Weather Conditions. J Med Entomol :
Margos, Gabriele; Lane, Robert S; Fedorova, Natalia et al. (2016) Borrelia bissettiae sp. nov. and Borrelia californiensis sp. nov. prevail in diverse enzootic transmission cycles. Int J Syst Evol Microbiol 66:1447-1452
Swei, Andrea; Briggs, Cheryl J; Lane, Robert S et al. (2012) Impacts of an introduced forest pathogen on the risk of Lyme disease in California. Vector Borne Zoonotic Dis 12:623-32
Lane, Robert S; Mun, Jeomhee; Peribáñez, Miguel A et al. (2010) Differences in prevalence of Borrelia burgdorferi and Anaplasma spp. infection among host-seeking Dermacentor occidentalis, Ixodes pacificus, and Ornithodoros coriaceus ticks in northwestern California. Ticks Tick Borne Dis 1:159-67
Eisen, Rebecca J; Eisen, Lars; Girard, Yvette A et al. (2010) A spatially-explicit model of acarological risk of exposure to Borrelia burgdorferi-infected Ixodes pacificus nymphs in northwestern California based on woodland type, temperature, and water vapor. Ticks Tick Borne Dis 1:35-43
Leonhard, Sarah; Jensen, Kelly; Salkeld, Daniel J et al. (2010) Distribution of the Lyme disease spirochete Borrelia burgdorferi in naturally and experimentally infected western gray squirrels (Sciurus griseus). Vector Borne Zoonotic Dis 10:441-6
Nieto, Nathan C; Leonhard, Sarah; Foley, Janet E et al. (2010) Coinfection of western gray squirrel (Sciurus griseus) and other sciurid rodents with Borrelia burgdorferi sensu stricto and Anaplasma phagocytophilum in California. J Wildl Dis 46:291-6
Salkeld, Daniel J; Lane, Robert S (2010) Community ecology and disease risk: lizards, squirrels, and the Lyme disease spirochete in California, USA. Ecology 91:293-8

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