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Avian migrants facilitate invasions of Neotropical ticks and tick-borne pathogens into the United States

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Complete Citation

  • Cohen, Emily B., Auckland, Lisa D., Marra, Peter P., and Hamer, Sarah A. 2015. "Avian migrants facilitate invasions of Neotropical ticks and tick-borne pathogens into the United States." Applied and Environmental Microbiology, 81, (24) 8366–8378. https://doi.org/10.1128/AEM.02656-15.

Overview

Abstract

  • Migratory birds have the potential to transport exotic vectors and pathogens of human and animal health importance across vast distances. We systematically examined birds that recently migrated to the United States from the Neotropics for ticks. We screened both ticks and birds for tick-borne pathogens including Rickettsia species and Borrelia burgdorferi. Over two spring seasons (2013-2014), 3.56% of birds (n = 3,844) representing 42.35% of species examined (n= 85) were infested by ticks. Ground foraging birds with reduced fuel stores were most commonly infested. Eight tick species were identified including seven in the genus Amblymma of which only Ambylomma maculatum/triste is known to be established in the United States. Most ticks on birds (67%) were Neotropical species with ranges in Central and South America. Additionally, a single Ixodes genus tick was detected. A total of 29% of ticks (n= 137) and no avian blood samples (n= 100), were positive for infection with Rickettsia species, including Rickettsia parkeri, an emerging cause of spotted fever in humans in the southern United States, a species in the group of Rickettsia monacensis, as well as uncharacterized species and endosymbionts of unknown pathogenicity. No avian tick or blood samples tested positive for Borrelia burgdorferi, the etiologic agent of Lyme disease. Extrapolation of our findings suggests that anywhere from 4 to 39 million exotic Neotropical ticks are transported to the United States annually on migratory songbirds, with uncertain consequences for human and animal health if the current barriers to their establishment and spread are overcome.

Publication Date

  • 2015