Infection with colorado tick Fever virus among humans and ticks in a national park and forest, wyoming, 2010.
Geissler AL1, Thorp E, Van Houten C, Lanciotti RS, Panella N, Cadwell BL, Murphy T, Staples JE.
Abstract Background: Colorado tick fever (CTF) is an underreported tick-borne viral disease occurring in the western United States.
CTF illness includes fever, headache, and severe myalgia lasting for weeks. Wyoming has one of the highest CTF incidence rates with approximately 30% of infected persons reporting tick exposure in a Wyoming National Park or Forest before symptom onset.
We assessed CTF virus infections among humans and Dermacentor andersoni ticks in Grand Teton National Park (GRTE) and Bridger-Teton National Forest (BTNF).
METHODS: In June of 2010, 526 eligible employees were approached to participate in a baseline and 3-month follow-up serosurvey and risk behavior survey.
Seropositivity was defined as antibody titers against CTF virus, as measured by the plaque reduction neutralization test.
Ticks were collected at 27 sites within GRTE/BTNF and tested by RT-PCR for the CTF virus.
RESULTS: A total of 126 (24%) employees participated in the baseline and follow-up study visits.
Three (2%) employees were seropositive for CTF virus infection at baseline.
During the study, 47 (37%) participants found unattached ticks on themselves, and 12 (10%) found attached ticks; however, no participants seroconverted against CTF virus.
Walking through sagebrush (p=0.04) and spending time at XX 7000 feet elevation were significantly associated with tick exposure.
Ninety-nine percent (174/176) of ticks were D. andersoni, and all were found at more than 7000 feet elevation in sagebrush areas; 37 (21%) ticks tested positive for CTF virus and were found at 10 (38%) of 26 sites sampled.
CONCLUSIONS: Although no GRTE or BTNF employees were infected with CTF virus during the study period, high rates of infected ticks were identified in areas with sagebrush at XX 7000 feet.
CTF education and personal protection measures against tick exposure should be targeted to visitors and employees traveling to the high-risk environs identified in this study.
Tincup
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Please note... I had to remove the "more than" and "less than" symbols so LymeNet would allow this post.
Please check the actual abstract/study to determine if it said "more than" 7,000 feet or "less than" 7,000 feet. Sorry for your troubles. Just too tired to argue with the LymeNet man inside my computer that won't allow the symbols.
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