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 ...201728082639
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 ...201727858931
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 ...201627263092
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. ...201829365130
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 ...201729284564
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 ...201729258802
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 ...201729178531
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.201728912318
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 ...201728882513
human behaviors elevating the risk of exposure to ixodes ricinus larvae and nymphs in two types of lowland coniferous forests in west-central poland.ixodes ricinus l. is the commonest tick encountered by humans in central europe and the most important vector of tick-borne diseases (tbd) in europe. foresters represent a group at elevated risk of exposure to i. ricinus throughout europe. here, we employed an experimental design similar to one used previously to determine what behavioral factors heighten exposure to questing ixodes pacificus nymphs in a hardwood forest in the far-western united states. five activities were evaluated systematica ...201627499188
effect of host lizard anemia on host choice and feeding rate of larval western black-legged ticks (ixodes pacificus).although ticks are known to exhibit preferences among host species, there is little evidence that ticks select hosts within a species based on physiological condition. it may be beneficial for ticks to choose hosts that are easier to feed upon if the ticks can perceive indicative chemical or other signals from the host. for example, if ticks can detect host hematocrit they may choose hosts with high hematocrit, facilitating a faster blood meal. it may similarly be adaptive for ticks to avoid ane ...201323760685
how do host sex and reproductive state affect host preference and feeding duration of ticks?parasitism is one of the most notable forms of symbiosis in the biological world, with nearly all organisms hosting parasites. in many vertebrates, males have higher ectoparasite burdens than females, especially when testosterone concentrations are elevated. furthermore, reproductive females may have higher ectoparasite burdens than non-reproductive females. it is possible that testosterone-stimulated behaviors in males and offspring investment by females incur energetic costs that inhibit immun ...201222526292
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