CONICET | Buscador de Institutos y Recursos Humanos

Haematophagous ectoparasites are worldwide vectors ofmany zoonotic bacterial diseases, both emerging and re-emerging, whose incidencesare rising. Livestock development alters different environmentalcharacteristics such as the microclimate of a site, changing the availability,density and susceptibility of the hosts to pathogens and vectors, indirectlyinfluencing the spread and persistence of a disease within an ecosystem. The Norwayrat (Rattus norvegicus), the most abundant vertebrate pest species foundon livestock farms from Argentina, is a reservoir for several importantzoonotic bacteria and may harbor ectoparasite species, which act as their vectors.Even though the Norway rat is widely known for its role as an ectoparasitehost, the ecological characteristics of their ectoparasite communities and the relatedfactors with parasitism on livestock farms have never been described. In thepresent study, we describe the ectoparasite community in Norway rats fromcentral Argentina livestock farms, while also depicting the influencing factorson both ectoparasite occurrence and abundance. Ectoparasites were collected fromrats captured in 20 sites from Buenos Aires province, between the winter of2016 and the summer of 2018. A total of 1441 ectoparasite individuals werecollected from 159 Norway rat individuals[Total ectoparasite prevalence = 69.2%; Mean ectoparasite specimen abundance (±CI) = 9.06 ± 2.32 ectoparasite individuals per rat; Mean ectoparasite specimen intensity (± CI) = 13.10 ± 3.08ectoparasite individuals per infested rat found]. Ectoparasite assemblage consistedof four cosmopolitan species, recognized for their sanitary relevance: mites(Laelapidae: Laelaps nuttalli and Laelaps echidninus), lice(Polyplacidae: Polyplax spinulosa) and fleas (Pulicidae: Xenopsyllacheopis). We observed higher Norway rat abundance in sites related to higherectoparasite occurrence and abundance frequencies on the rats. Additionally, ectoparasiteswere more abundant on rats in warm seasons and on male individuals, over femalerats. Moreover, the geographical location of the studied sites influenced theectoparasite assemblage structure observed on the rats. Thisstudy broadens the knowledge on the role of Norway rats as zoonotic ectoparasites hosts and analyzes thedrivers influencing ectoparasite occurrence and abundance on the most populatedregion of Argentina, which is also the region with the most intensive livestockfarming. Therefore, this survey may assist in evaluating potential risks forhumans and generate effective sanitary control strategies forectoparasite-borne infectious diseases.