Results for “Ixodes pacificus”

PubMed1976

Isolation of a spotted fever group rickettsia from the Pacific Coast tick, Ixodes pacificus, in Oregon.

A rickettsia of the spotted fever group was isolated on three occasions from Ixodes pacificus in western Oregon. These isolations, and additional evidence furnished by complement fixation tests on guinea pigs inoculated with other Oregon ticks of this species, indicate that the association of this rickettsia with the Pacific Coast tick may be widespread. This is the first isolation of a spotted fever group rickettsia from I. pacificus. Because the Oregon isolates are mildly virulent for guinea pigs they resemble the Western U and Rickettsia montana strains of rickettsiae. However, preliminary evidence from cross-immunofluorescence tests of mouse antisera suggests the Tillamook and Grants Pass strains are antigenically different from all known spotted fever group agents.

Animals↗

PubMed1977

The distribution in Oregon of Ixodes pacificus, Dermacentor andersoni, and Dermacentor occidentalis with a note on Dermacentor variabilis (Acarina: Ixodidae).

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Animals↗

PubMed2026

Detection of Rickettsia species with seroreactivity to Rickettsia tillamookensis and Rickettsia rickettsii subsp. californica in domestic dogs in Northern California.

Rickettsia species phylotype G022 (G022) and Rickettsia tillamookensis both maintain a low infection prevalence in Ixodes pacificus ticks and share a close phylogenetic history with pathogenic Rickettsia species. The transmission mechanisms and pathogenic potential of I. pacificus-borne Rickettsia are poorly understood. The low prevalence of G022 and R. tillamookensis suggests that vertebrate species are utilized for maintenance, though identification of vertebrate amplifier and reservoir hosts utilized by Rickettsia is limited. To evaluate the molecular occurrence of G022 and R. tillamookensis and the sentinel utility of domestic dogs, a molecular survey was conducted. Buffy coat and blood plasma samples from 175 domestic dogs collected from Humboldt and Sonoma counties in northern California were screened for rickettsial DNA and anti-rickettsial antibodies, respectively. Dogs were screened for antibodies against Rickettsia spp. and tested for seroreactivity against R. tillamookensis, Rickettsia rickettsii subsp. californica, and Rickettsia rhipicephali. Because G022 has not yet been isolated, this Rickettsia species was omitted from the serological survey. Of the 175 dogs tested, three (1.71%; 95% CI: 0.58%-4.90%) were seropositive for Rickettsia spp. by indirect immunofluorescence antibody assay (IFA); two dogs (1.14%; 95% CI: 0.31%-4.10%) demonstrated seroreactivity by enzyme-linked immunosorbent assay (ELISA), suggesting previous exposure to Rickettsia spp. Among dogs from Sonoma County, 2.88% (3/104; 95% CI: 1.0%-8.14%) of plasma samples were seropositive for Rickettsia spp. by IFA, and 1.92% (2/104; 95% CI: 0.53%-6.74%) demonstrated seroreactivity by ELISA, while all the dogs from Humboldt County were seronegative for both methods. Although the ELISA results were not considered species-specific, two plasma samples demonstrated the greatest seroreactivity against R. tillamookensis and R. rickettsii subsp. californica, respectively, suggesting previous exposure to Rickettsia spp. with epitope similarity to R. tillamookensis and R. rickettsii subsp. californica, respectively. No DNA was detected for G022 or R. tillamookensis by quantitative real-time PCR, with a limit of detection of approximately 3.6 target copies per reaction for G022 and 1 genomic copy per 2 μl of template DNA per reaction for R. tillamookensis.

Animals↗

PubMed1979

Cases of Lyme disease in the United States: locations correlated with distribution of Ixodes dammini.

Lyme disease, defined by erythema chronicum migrans and sometimes followed by neurologic, cardiac, or joint involvement, is known to have affected 512 patients in the United States. The disease seems to occur in three distinct foci: along the northeastern coast, in Wisconsin, and in California and Oregon, a distribution that correlates closely with that of Ixodes dammini in the first two areas and with Ixodes pacificus in the last. The implicated tick, saved by six patients in the Northeast, was identified as nymphal I. dammini. Residence in or travel to endemic areas and history of tick bite may be important clues to diagnosis.

Arachnid Vectors↗