Ecology of the interaction between Ixodes loricatus (Acari: Ixodidae) and Akodon azarae (Rodentia: Cricetidae).

COLOMBO, V.; NAVA, S.; ANTONIAZZI, L.R.; MONJE, L.D.; RACCA, A; GUGLIELMONE, A.A; BELDOMÉNICO, P.M.

PARASITOLOGY RESEARCH

SPRINGER

Lugar: Berlin; Año: 2015 vol. 114 p. 3683 - 3691

0932-0113

The present study explores associations of different factors (i.e. environmental, host parameters, presence of other ectoparasites) with burdens of Ixodes loricatus immature stages in one of its main hosts, the rodent Akodon azarae. Monthly and for two years, rodents were trapped and sampled at 16 points located at 4 different sites in the Parana River Delta region. Data were analyzed with Generalized Linear Mixed Models with a negative binomial response (counts of larvae or nymphs). The independent variables assessed were: a) environmental: trapping year, presence of cattle, type of vegetation, rodent abundance b) host parameters: body length, sex, body condition, blood cell counts, natural antibody titers and c) co-infection with other ectoparasites. Two-way interaction terms deemed a priori as relevant were also included in the analysis. Most of the associations investigated were found significant, but in general the direction and magnitude of the associations were context-dependent. An exception was the presence of cattle, which was consistently negatively associated with both larvae and nymphs independently of all other variables considered, and had the strongest effect on tick burdens. Mites, fleas and A. triste were also significantly associated (mostly positively) with larval and nymph burdens, and in many cases they influenced associations with environmental or host factors. Our finding strongly support that land use change for cattle raising may have a substantial impact on the dynamics of I. loricatus; and that interactions within the ectoparasite community may be an important ? but generally ignored ? driver of tick dynamics.