[Ectoparasites of rodents of the urban region of Belo Horizonte, MG. I. Interaction between ectoparasites and hosts].

A rodent ectoparasite survey was made in the city of Belo Horizonte, Minas Gerais, Brazil, from June 1980 to September 1982. The species of ectoparasites captured from 950 Rattus norvegicus norvegicus were: Xenopsylla cheopis, Ctenocephalides felis felis, Polyplax spinulosa, Laelaps nuttalli, Echinolaelaps echidninus and Atricholaelaps glasgowi, the last species only represented by three specimens interchanged with wild rodent. P. spinulosa and L. nuttalli, although cosmopolitan, are recorded for the first time in State of Minas Gerais. The sex ratio of the ectoparasites, as well as the prevalence of fleas, mites and lice on the separate sexes of rodents are presented. 66.9% of the rats were infested by mites, almost twice more than infestations by fleas and louse jointly (39%). L. nuttalli was found in great numbers and presented the highest index of infestation: 55.1%. Single infestations are as common as associated ones. P. spinulosa, contrary to L. nuttalli, rarely occurs in single infestation. Data on the distribution of the ectoparasites on the rodents are also reported. The infestation observed in Belo Horizonte is confronted with those obtained by other authors in different places.