Borreliacidal activity of saliva of the tick Amblyomma americanum

Authors

  • K. E. Ledin,

    1. Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, U.S.A.,
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  • N. S. Zeidner,

    Corresponding author
    1. Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, U.S.A.,
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  • J. M. C. Ribeiro,

    1. Laboratory of Malaria and Vector Research, Section of Vector Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, U.S.A. and
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  • B. J. Biggerstaff,

    1. Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, U.S.A.,
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  • M. C. Dolan,

    1. Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, U.S.A.,
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  • G. Dietrich,

    1. Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, U.S.A.,
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  • L. VredEvoe,

    1. Biological Sciences Department, California Polytechnic State University, San Luis Obispo, California, U.S.A.
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  • J. Piesman

    1. Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, U.S.A.,
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*Nordin S. Zeidner, Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, PO Box 2087, Fort Collins, CO 80522, U.S.A. Tel.: +1 970 221 6495; fax: +1 970 225 4257; e-mail: naz2@cdc.gov

Abstract

Abstract. Amblyomma americanum (Linneaus) (Acari: Ixodidae), an important tick vector of human and animal disease, is not a competent vector of the bacterial agent of Lyme disease, Borrelia burgdorferi, although its range overlaps the geographical distribution of Lyme disease within the United States. A possible mechanism that could prevent acquisition of B. burgdorferi spirochetes from infected hosts is the toxic effect of A. americanum saliva on B. burgdorferi. The data presented here indicate that after 24 and 48 h of exposure to A. americanum saliva, significantly fewer B. burgdorferi were alive compared to treatment controls as assessed by spirochete motility under dark-field microscopy and resistance to the dead stain, propidium iodide. After 48 h, fewer than 13% of saliva-exposed B. burgdorferi were alive. In contrast, significantly more B. burgdorferi exposed to Ixodes scapularis (Acari: Ixodidae) saliva survived after 24 or 48 h compared to A. americanum saliva or treatment controls.

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