Emerging Infectious Diseases Journal Volume 14, Number 3-March 2008 Letter
Novel Relapsing Fever Spirochete in Bat Tick
James S. Gill,* Amy J. Ullmann,� Amanda D. Loftis,� Tom G. Schwan,� Sandra J. Raffel,� Merry E. Schrumpf, � and Joseph Piesman� *Iowa State University, Ames, Iowa, USA; �Centers for Disease Control and Prevention, Fort Collins, Colorado, USA; �Centers for Disease Control and Prevention, Atlanta, Georgia, USA; and �Rocky Mountain Laboratories of National Institutes of Health, Hamilton, Montana, USA
To the Editor: Tick-borne relapsing fever in western North America is a zoonosis caused by spirochetes in the genus Borrelia that are transmitted by argasid ticks of the genus Ornithodoros (1). Human disease occurs in many focal areas and is associated with infections of Borrelia hermsii, B. turicatae, and possibly B. parkeri (2,3). Although the ecologic parameters that maintain B. hermsii and B. turicatae differ, human infections usually occur in rustic cabins (B. hermsii) and caves (B. turicatae) inhabited by ticks and their terrestrial vertebrate hosts (1). Recently, Gill et al. (4) provided evidence that the argasid bat tick, Carios kelleyi, feeds upon humans. Subsequently, Loftis et al. (5) used PCR analysis and DNA sequencing to detect in C. kelleyi an unidentified Borrelia species that was closely related to B. turicatae and B. parkeri.
We report the partial molecular characterization of another novel tick-borne relapsing fever spirochete in C. kelleyi, which expands our knowledge for this group of pathogenic spirochetes and their potential vertebrate hosts and tick vectors.
C. kelleyi were collected August 18, 2005, from a house in Jones County, Iowa, built in 1857. Bats had been excluded from the attic since 1992. Nine months before ticks were collected, bats were prevented from roosting under the eaves. DNA was extracted from 31 nymphal C. kelleyi, as described previously (6). For each tick, regions of the glpQ, flaB, and 16S rRNA genes were amplified and sequenced as described (3,7,8). Sequences were assembled by using the SeqMan program in the Lasergene software package (DNASTAR, Madison, WI, USA).
Figure
Figure. Phylogram comparing the novel spirochete in the bat tick Carios kelleyi with Borrelia parkeri, B. turicatae, and B. hermsii based on the concatenated partial 16S rRNA-flaB-glpQ DNA sequences...
Fourteen (45.1%) of 31 ticks were positive by PCR for >1 of the genes tested. Partial DNA sequences were determined from tick no. 16, for which amplicons for all 3 genes were obtained. The partial flaB sequence had 4 bases different from the 300-base sequence (98.66% identity) reported previously (GenBank accession no. AY763104) for another Borrelia sp. found in C. kelleyi (5). We constructed a 1,992-bp concatenated sequence that contained 1,273 bp of the 16S rRNA, 351 bp of flaB, and 368 bp of glpQ. This concatenated sequence was aligned with homologous, trimmed DNA sequences of the same length obtained from representative full-length sequences determined previously for B. hermsii, B. turicatae, and B. parkeri (3,9) (Figure). This C. kelleyi spirochete was more closely related to B. turicatae and B. parkeri than to B. hermsii but was clearly distinct from all 3 species (DNA sequence identities of 98.89%, 98.75%, and 95.98% to B. turicatae, B. parkeri, and B. hermsii, respectively).
A glpQ amplicon from another nymphal tick (no. 3) was sequenced (GenBank accession no. EF688578) and was unique in the database; it was also considerably different from the glpQ sequence determined from tick 16, with 325 of 368 bases matching (88.3% identity). The Borrelia glpQ sequence from tick 3 had 85.1%-89.1% identity compared with glpQ sequences from B. hermsii, B. turicatae, and B. parkeri. This finding suggests the presence of at least 2 relapsing fever group spirochetes in C. kelleyi that await further characterization.
We found a novel Borrelia in bat ticks that is closely related to, but distinct from, the other known species of tick-borne relapsing fever spirochetes in North America. The human health implications of the new relapsing fever group spirochete are not yet known. The willingness of C. kelleyi to feed on humans and the fact that infection with bacteria closely related to true relapsing fever spirochetes occurs in these ticks suggest that human habitation near bats and their associated tick colonies could pose a public health risk. Growth in laboratory animals or culture could help isolate these novel organisms for further studies to establish the distribution and public health implications of this newly identified Borrelia sp.
Acknowledgments We thank M.J.R. Gilchrist and the University of Iowa Hygienic Laboratory for support, and G. Hettrick and J. Gathany for help with the figure.
This work was supported in part by the Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health.
References Dworkin MS, Schwan TG, Anderson DE. Tick-borne relapsing fever in North America. Med Clin North Am. 2002;86:417-33.
Schwan TG, Raffel SJ, Schrumpf ME, Porcella SF. Diversity and distribution of Borrelia hermsii. Emerg Infect Dis. 2007;13:436-42.
Schwan TG, Raffel SJ, Schrumpf ME, Policastro PF, Rawlings JA, Lane RS, et al. Phylogenetic analysis of the spirochetes Borrelia parkeri and Borrelia turicatae and the potential for tick-borne relasping fever in Florida. J Clin Microbiol. 2005;43:3851-9.
Gill JS, Rowley WA, Bush PJ, Viner JP, Gilchrist MJ. Detection of human blood in the bat tick Carios (Ornithodoros) kelleyi (Acari: Argasidae) in Iowa. J Med Entomol. 2004;41:1179-81.
Loftis AD, Gill JS, Schriefer ME, Levin ML, Eremeeva ME, Gilchrist MJ, et al. Detection of Rickettsia, Borrelia, and Bartonella in Carios kelleyi (Acari: Argasidae). J Med Entomol. 2005;42:473-80.
Zeidner NS, Burkot TR, Massung R, Nicholson WL, Dolan MC, Rutherford JS, et al. Transmission of the agent of human granulocytic ehrlichiosis by Ixodes spinipalpis ticks: evidence of an enzootic cycle of dual infection with Borrelia burgdorferi in northern Colorado. J Infect Dis. 2000;182:616-9.
Bacon RM, Pilgard MA, Johnson BJ, Raffel SJ, Schwan TG. Glycerophosphodiester phosphodiesterase gene (glpQ) of Borrelia lonestari identified as a target for differentiating Borrelia species associated with hard ticks (Acari: Ixodidae). J Clin Microbiol. 2004;42:2326-8.
Johnson BJ, Happ CM, Mayer LW, Piesman J. Detection of Borrelia burgdorferi in ticks by species-specific amplification of the flagellin gene. Am J Trop Med Hyg. 1992;47:730-41.
Porcella SF, Raffel SJ, Anderson DE Jr, Gilk SD, Bono JL, Schrumpf ME, et al. Variable tick protein in two genomic groups of the relapsing fever spirochete Borrelia hermsii in western North America. Infect Immun. 2005;73:6647-58.
Figure Figure. Phylogram comparing the novel spirochete in the bat tick Carios kelleyi with Borrelia parkeri, B. turicatae, and B. hermsii based on the concatenated partial 16S rRNA-flaB-glpQ DNA sequences...
Suggested Citation for this Article Gill JS, Ullmann AJ, Loftis AD, Schwan TG, Raffel SJ, Schrumpf ME, et al. Novel relapsing fever spirochete in bat tick [letter]. Emerg Infect Dis [serial on the Internet]. 2008 Mar [date cited]. Available from http://www.cdc.gov/EID/content/14/3/522.htm
Comments to the Authors Please use the form below to submit correspondence to the authors or contact them at the following address:
James S. Gill, 313 N Mt Vernon Dr, Iowa City, IA 52245, USA; email: [email protected]
This page posted February 26, 2008 This page last reviewed February 26, 2008
I wouldnt be surprized with what disease are here in the USA .
Look at the Brown Bat in New York there dying they get a fungus on there nose its white right before they die. I saw a program on it and the to biologists were in the cave showing them but get this they had no protection over there nose or mouth or hands what bozos dont know what it is yet they go in unprotected.
Posted by Melanie Reber (Member # 3707) on :
Thanks Ima! Posted by map1131 (Member # 2022) on :
Tree, I read that story on the fungus found on dead bats. It didn't surprise me none that something in the world is making even strange things happen to bats.
Fungus, huh? I wonder if they got to work right away to save the bats from this fungus? Sorry, that was not a bat friendly attitude. I'm sorry.
I know what effects every living thing on our planet can also effect humans. Study of animals, birds, mice, etc, is important to humans health and well-being.
Pam
Posted by Cold Feet (Member # 9882) on :
I've been digging for news on the bat disease here in the northeast, with no news yet. Last I read, it was looking like the bats had "pneumonia-like" symptoms.
The referenced footnotes at the end of the article are alarming for so many reasons!
I am looking for the other recent topics on bats-- but this topic is germane too. So, here is a Canadian report of the disease "isolated" to New England:
March 27, 2008 Bat killer alerts wildlife officials By FRANK LANDRY, CITY HALL BUREAU
A mysterious disease that's been killing bats south of the border has Alberta wildlife officials on alert.
``We're definitely watching the situation,'' said Darcy Whiteside, a spokesman with Alberta Sustainable Resource Development. ``It seems to be very isolated. But it is a very devastating disease.''
There are reports of bats in New York and Vermont mysteriously dying off by the thousands, often with a white ring of fungus around their noses.
The killer, spreading at an alarming rate, has been dubbed ``white nose syndrome.'' Researchers have called it the gravest threat in recent memory to bats in the U.S.
While it has not been detected here, Whiteside said the province is working with the Alberta Bat Action Team, a group of bat enthusiasts interested in conservation, to monitor the situation.
``If there were large deaths in bats, we would definitely have a heads up on it from this action team,'' he said.
In the meantime, he stressed the public has nothing to fear. Bats play a very important role in keeping a lid on the insect population, he said.
``There really should be no worry.''
Mike Jenkins, with the city's pest management branch, said city officials have been talking about the situation in the eastern U.S., but like their provincial counterparts, have seen no sign of it in Edmonton.
It's not clear if the white fungus around the bats' noses is a cause or a symptom. It may be a sign the bats are too sick to groom themselves, according to reports.
According to the province, nine species of bats have been identified in Alberta, but only three species are encountered frequently by people. They feed almost exclusively on flying insects.
A typical colony of little brown bats can eat up to 50 kg of insects during one summer, Alberta Sustainable Resource Development reports on its website.
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