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Infection intensity and infectivity of the tick‐borne pathogen Borrelia afzelii
Author(s) -
RÅBERG L
Publication year - 2012
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2012.02515.x
Subject(s) - biology , infectivity , borrelia afzelii , tick , virulence , pathogen , borrelia burgdorferi , host (biology) , transmission (telecommunications) , borrelia , rodent , bank vole , vector (molecular biology) , zoology , microbiology and biotechnology , virology , ecology , virus , immunology , genetics , gene , demography , population , recombinant dna , electrical engineering , sociology , antibody , engineering
Abstract The ‘trade‐off’ hypothesis for virulence evolution assumes that between‐host transmission rate is a positive and saturating function of pathogen exploitation and virulence, but there are as yet few tests of this assumption, in particular for vector‐borne pathogens. Here, I show that the infectivity (probability of transmission) of the tick‐borne bacterium Borrelia afzelii from two of its natural rodent hosts (bank vole and yellow‐necked mouse) to its main tick vector increases asymptotically with increasing exploitation (measured as bacterial load in skin biopsies). Hence, this result provides support for one of the basic assumptions of the ‘trade‐off hypothesis’. Moreover, there was no difference in infectivity between bank voles and yellow‐necked mice despite bacterial loads being on average an order of magnitude higher in bank voles, most likely because ticks took larger blood meals from mice. This shows that interspecific variation in host resistance does not necessarily translate into a difference in infectivity.