The Eurasian otter (Lutra lutra) as a potential host for rickettsial pathogens in southern Italy

Mario Santoro,Nicola D’Alessio,Maria Gabriella Lucibelli,Giorgio Galiero,Giorgia Borriello,Anna Cerrone,Gaetano Aloise,Nunzia Riccone,Clementina Auriemma,J Stephen Dumler

doi:10.1371/journal.pone.0173556

Mario Santoro, Nicola D’Alessio + Show 8 more

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https://doi.org/10.1371/journal.pone.0173556

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Abstract

Canine monocytic ehrlichiosis and rickettsiosis are zoonotic tick-borne diseases of canids caused by the intracellular obligate bacteria Ehrlichia canis and Rickettsia species respectively. In this study, we investigated using standard and real-time PCR and sequencing, the occurrence and molecular characterization of E. canis and Rickettsia species in the Eurasian otter (Lutra lutra) from the southern Italian population. Samples were screened by using molecular assays also for Neospora caninum, Toxoplasma gondii, Clamydophyla spp., Coxiella burnetii, Leishmania spp., Cryptosporidium spp., and Giardia spp. detection, and helminths were studied by traditional methods. Out of six carcasses tested, three were positive for E. canis and co-infection with Rickettsia sp. occurred in one of those. Sequences of the 16S rRNA E. canis gene were identical to each other but differed from most of those previously found in red foxes (Vulpes vulpes) and wolves (Canis lupus) from southern Italy. Helminths included just cystacanths of Sphaerirostris spp. from the intestine of two Eurasian otters and the nematode Angiostrongylus vasorum from the lungs of a single Eurasian otter. None of the samples was positive for the other investigated selected pathogens. This study is the first report on the evidence of infection by rickettsial pathogens in the Eurasian otter. The present result prompts some inquiries into the pathogenic role of those bacteria for the isolated sub-populations of the endangered Eurasian otter in southern Italy.

Highlights

Canine monocytic ehrlichiosis (CME) and rickettsiosis are zoonotic tick-borne diseases of canids caused by the intracellular obligate bacteria Ehrlichia canis and Rickettsia species respectively [1,2,3,4,5]
Three (ID 79797; 79829; 130699) out of six carcasses were positive to E. canis by rt PCR, all coming from Capaccio (Salerno province), and one of those (ID 79829) was positive for Rickettsia sp. by standard PCR (Table 1)
E. canis sequenced amplicons were identical and they showed a high nucleotide similarity (99.4%) with E. canis 16S rRNA gene sequences found in a dog (GQ857078) and foxes and wolves (KX371787, 99.5%; KX371788, 99%; KX371789, 99%) and 100% similarity with an E. canis 16S rRNA gene sequence found in red foxes from southern Italy (KX371786) available in GenBank accession number

Summary

Introduction

Canine monocytic ehrlichiosis (CME) and rickettsiosis are zoonotic tick-borne diseases of canids caused by the intracellular obligate bacteria Ehrlichia canis and Rickettsia species respectively [1,2,3,4,5]. Both CME and many Rickettsia spp. are endemic in all European countries bordering the Mediterranean Sea [3,4,6]. Among rickettsial pathogens of the spotted fever group, R. conorii is the most common being the causative agent of the Mediterranean spotted fever in humans [2]. The brown dog tick Rhipicephalus sanguineus sensu lato (s.l.) is generally accepted as the main vector for both E. canis and R. conorii infections and suspected as the main reservoir for R. conorii [2,3].

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