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

COLOMBO VC, NAVA S, ANTONIAZZI LR, MONJE LD, RACCA AL, GUGLIELMONE AA, BELDOMENICO PM.

PARASITOLOGY RESEARCH

SPRINGER

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

0932-0113

Abstract The present study explores associations of differentfactors (i.e. host parameters, presence of other ectoparasitesand [mainly biotic] environmental factors) with burdens ofIxodes loricatus immature stages in one of its main hosts inArgentina, the rodent Akodon azarae. For 2 years, rodentswere trapped and sampled monthly at 16 points located in fourdifferent sites in the Parana River Delta region. Data wereanalysed with generalized linear mixed models with a negativebinomial response (counts of larvae or nymphs). The independentvariables assessed were (a) environmental: trappingyear, 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-infestationwith other ectoparasites. Two-way interaction terms deemed apriori as relevant were also included in the analysis. Most ofthe associations investigated were found significant, but ingeneral, the direction and magnitude of the associations werecontext-dependent. An exception was the presence of cattle,which was consistently negatively associated with both larvaeand nymphs independently of all other variables consideredand had the strongest effect on tick burdens. Mites, fleas andAmblyomma triste were also significantly associated (mostlypositively) with larval and nymph burdens, and in many cases,they influenced associations with environmental or host factors.