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Predicting the rate of invasion of the agent of Lyme disease Borrelia burgdorferi
Author(s) -
Ogden Nicholas H.,
Lindsay L. Robbin,
Leighton Patrick A.
Publication year - 2013
Publication title -
journal of applied ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.503
H-Index - 181
eISSN - 1365-2664
pISSN - 0021-8901
DOI - 10.1111/1365-2664.12050
Subject(s) - borrelia burgdorferi , ixodes scapularis , tick , nymph , lyme disease , biology , zoology , larva , ecology , range (aeronautics) , ixodidae , virology , immunology , antibody , materials science , composite material
Summary Identifying invading tick populations provides early warning for emerging tickborne diseases that are expanding their geographic range. But how fast do tickborne pathogens invade after ticks become established? Surveillance data for the tick I xodes scapularis and the agent of L yme disease B orrelia burgdorferi in southern C anada, an area where these species currently are invading, revealed a space‐time cluster of ticks of low B . burgdorferi infection prevalence in southern Q uebec signalling the location where tick populations became established beginning in 2004. The cluster disappeared in 2009, indicating a 5‐year gap between tick and B . burgdorferi invasion. Simulations of a model of I . scapularis populations and B . burgdorferi transmission identified numbers of immigrating ticks, rather than host density and diversity, as key determinants of the speed of pathogen invasion after ticks become established. Greater numbers of immigrating infected nymphs would be expected in Central compared with E astern C anada because nymphal and larval ticks in source populations in M idwestern USA are active in spring when migratory birds can carry ticks north. Whereas in northeastern USA , tick populations that are sources for immigrating ticks for E astern C anada have active nymphs, but few larvae are active in spring. Consequently, we hypothesized that a 5‐year gap would occur between tick and B . burgdorferi invasion in E astern C anada, but a much shorter gap would occur in C entral C anada. Consistent with this hypothesis, analysis of surveillance data revealed clusters of ticks with low infection prevalence of ≥5 years duration in locations in E astern C anada where I . scapularis is invading, but a nonsignificant cluster of only 3‐year duration in regions of C entral C anada where I . scapularis is invading. Synthesis and applications . We have identified the speed at which the pathogen B orrelia burgdorferi invades following the invasion of the tick I xodes scapularis , and that the synchrony of larval and nymphal tick activity in spring is a key factor determining the gap between tick and pathogen invasion. This has immediate application in interpreting imminence of L yme disease risk when surveillance identifies emerging tick populations in C anada. It also has general application in predicting of the speed of invasion of emerging tickborne pathogens elsewhere in the world.