Publications

diapause in ticks of the medically important ixodes ricinus species complex.	four members of the ixodes ricinus species complex, ixodes pacificus, ixodes persulcatus, ixodes ricinus and ixodes scapularis, have, between them, a worldwide distribution within the northern hemisphere. they are responsible for the transmission of several animal and human pathogens, including the causal agents of lyme borreliosis, tick-borne encephalitis, human granulocytic anaplasmosis and human babesiosis. despite the importance of these ticks as vectors, the knowledge and understanding of t ...	2016	27263092
a molecular algorithm to detect and differentiate human pathogens infecting ixodes scapularis and ixodes pacificus (acari: ixodidae).	the incidence and geographic range of tick-borne illness associated with ixodes scapularis and ixodes pacificus have dramatically increased in recent decades. anaplasmosis, babesiosis, and borrelia spirochete infections, including lyme borreliosis, account for tens of thousands of reported cases of tick-borne disease every year. assays that reliably detect pathogens in ticks allow investigators and public health agencies to estimate the geographic distribution of human pathogens, assess geograph ...	2017	29258802
vertical vs. horizontal transmission of the microbiome in a key disease vector, ixodes pacificus.	vector-borne pathogens are increasingly found to interact with the vector's microbiome, influencing disease transmission dynamics. however, the processes that regulate the formation and development of the microbiome are largely unexplored for most tick species, an emerging group of disease vectors. it is not known how much of the tick microbiome is acquired through vertical transmission vs. horizontally from the environment or interactions with bloodmeal sources. using 16s rrna sequencing, we ex ...	2017	29178531
host-seeking phenology of ixodes pacificus (acari: ixodidae) nymphs in northwestern california in relation to calendar week, woodland type, and weather conditions.	local knowledge of when humans are at elevated risk for exposure to tick vectors of human disease agents is required both for the effective use of personal protection measures to avoid tick bites and for implementation of control measures to suppress host-seeking ticks. here, we used previously published data on the seasonal density of host-seeking ixodes pacificus cooley and kohls nymphs, the primary vectors of lyme disease spirochetes in the far western usa, collected across a broad habitat an ...	2017	28082639
tick microbiome and pathogen acquisition altered by host blood meal.	lyme disease, a zoonotic disease, is the most prevalent vector-borne disease in the northern hemisphere. diversity of the vector (tick) microbiome can impact pathogen transmission, yet the biotic and abiotic factors that drive microbiome diversity are largely unresolved, especially under natural, field conditions. we describe the microbiome of ixodes pacificus ticks, the vector for lyme disease in the western united states, and show a strong impact of host blood meal identity on tick microbiome ...	2017	27858931
the fola gene from the rickettsia endosymbiont of ixodes pacificus encodes a functional dihydrofolate reductase enzyme.	although nonpathogenic bacterial endosymbionts have been shown to contribute to their arthropod host's fitness by supplying them with essential vitamins and amino acids, little is known about the nutritional basis for the symbiotic relationship of endosymbionts in ticks. our lab has previously reported that rickettsia species phylotype g021 in ixodes pacificus carries all five genes for de novo folate synthesis, and that these genes are monophyletic with homologs from other rickettsia species. i ...	2017	29284564
chromosome and large linear plasmid sequences of a borrelia miyamotoi strain isolated from ixodes pacificus ticks from california.	borrelia miyamotoi, a relapsing fever group spirochete, is an emerging tick-borne pathogen. it has been identified in ixodid ticks across the northern hemisphere, including the west coast of the united states. we describe the chromosome and large linear plasmid sequence of a b. miyamotoi isolate cultured from a california field-collected ixodes pacificus tick.	2017	28912318
enhanced detection of rickettsia species in ixodes pacificus using highly sensitive fluorescence in situ hybridization coupled with tyramide signal amplification.	ixodes pacificus is a host of many bacteria including rickettsia species phylotypes g021 and g022. as part of the overall goal of understanding interactions of phylotypes with their tick host, this study focused on molecular detection of rickettsiae in ovarian and midgut tissue of i. pacificus by fluorescent in situ hybridization (fish), pcr, and ultrastructural analysis. of three embedding media (technovit 8100, unicryl, and paraffin) tested for generating thin sections, tissues embedded in par ...	2017	28882513
detection of borrelia genomospecies 2 in ixodes spinipalpis ticks collected from a rabbit in canada.	lyme disease is a serious health problem, with many patients requiring in-depth clinical assessment and extended treatment. in the present study, we provide the first records of the western blacklegged tick, ixodes pacificus , and ixodes spinipalpis parasitizing eastern cottontails, sylvilagus floridanus . we also documented a triple co-infestation of 3 tick species (ixodes angustus, i. pacificus , i. spinipalpis) feeding on an eastern cottontail. notably, we discovered a unique member of the ly ...	2017	27835071
lyme disease risk in southern california: abiotic and environmental drivers of ixodes pacificus (acari: ixodidae) density and infection prevalence with borrelia burgdorferi.	tick-borne diseases, particularly lyme disease, are emerging across the northern hemisphere. in order to manage emerging diseases and predict where emergence will likely occur, it is necessary to understand the factors influencing the distribution, abundance and infection prevalence of vector species. in north america, lyme disease is the most common vector-borne disease and is transmitted by blacklegged ticks. this study aimed to explore the abiotic and environmental drivers of density and infe ...	2017	28057067
diversity of rickettsiae in a rural community in northern california.	far northern california forests are highly biodiverse in wildlife reservoirs and arthropod vectors that may propagate rickettsial pathogens in nature. the proximity of small rural communities to these forests puts people and domestic animals at risk of vector-borne infection due to spillover from wildlife. the current study was conducted to document exposure to rickettsial pathogens in people and domestic animals in a rural community, and identify which rickettsiae are present in sylvatic and pe ...	2017	28274808
prevalence and geographic distribution of borrelia miyamotoi in host-seeking ixodes pacificus (acari: ixodidae) nymphs in mendocino county, california.	borrelia miyamotoi is an increasingly recognized human pathogen transmitted by ixodes ticks in the northern hemisphere. in north america, infection prevalences of b. miyamotoi are characteristically low (<10%) in ixodes scapularis (say; acari: ixodidae) and ixodes pacificus (cooley & kohls; acari: ixodidae), both of which readily bite humans. we tested 3,255 host-seeking i. pacificus nymphs collected in 2004 from 79 sites throughout mendocino county in north-coastal california for presence of b. ...	2018	29365130