Zoonotic Bartonella species in Eurasian wolves and other free-ranging wild mammals from Italy

Abstract

Bartonellae are emerging vector-borne pathogens infecting humans, domestic mammals and wildlife. Ninety-seven red foxes (Vulpes vulpes), 8 European badgers (Meles meles), 6 Eurasian wolves (Canis lupus), 6 European hedgehogs (Erinaceus europaeus), 3 beech martens (Martes foina) and 2 roe deer (Capreolus capreolus) from Italian Nature Conservatory Parks were investigated for Bartonella infection. Several Bartonella species (9.84%; 95% CI: 4.55-15.12), including zoonotic ones, were molecularly detected among wolves (83.3%; 95% CI: 51-100.00), foxes (4.12%; 95% CI: 0.17-8.08), hedgehogs (33.33%; 95% CI: 0.00-71.05) and a roe deer. Bartonella rochalimae was the most common Bartonella species (i.e. in 4 foxes and 2 wolves) detected. Candidatus B. merieuxii and B. vinsonii subsp. berkhoffii were identified for the first time in wolves. Furthermore, Bartonella schoenbuchensis was identified in a roe deer and a new clone with phylogenetic proximity to B. clarridgeiae was detected in European hedgehogs. Zoonotic and other Bartonella species were significantly more frequent in Eurasian wolves (p < .0001), than in other free-ranging wild mammals, representing a potential reservoir for infection in humans and domestic animals.

Keywords: Bartonella; Eurasian wolf; hedgehog; red fox; roe deer; zoonosis.

FIGURE 1

(a) Sampling sites, number and distribution of wolves, red foxes, badgers, martens, roe deer and hedgehogs according to the administrative regional and provincial boundaries of the study area: Campania region (AV ‐ Avellino, BN ‐ Benevento, CE ‐ Caserta, NA ‐ Naples, SA – Salerno); Basilicata region (PZ ‐ Potenza, MT ‐ Matera). (b) Number and distribution of wildlife positive to different Bartonella species according to the administrative regional and provincial boundaries of the study area. Campania region (AV ‐ Avellino, BN ‐ Benevento, CE ‐ Caserta, NA ‐ Naples, SA – Salerno); Basilicata region (PZ ‐ Potenza, MT ‐ Matera)

FIGURE 2

Phylogenetic trees displaying the diversity of Bartonella species detected in wild mammals from Italy. The phylogenetic trees for partial ITS (600 bp) (panel a) and rpoB (357 bp) (panel b) sequences from representative known Bartonella isolates were generated by using MEGA‐X v. 10.0.5 software. Maximum likelihood method with Tamura Nei 3‐parameter substitution model, a proportion of invariable sites and a gamma distribution of rate variation across sites was applied supplying statistical support with subsampling over 1,000 replicates. GenBank accession numbers are provided for reference isolates with the sequence from Brucella abortus (AE017223) used as outgroup. The representative sequences generated in the present study are marked with arrows. Asterisks denote the nucleotide sequences identical to strains retrieved from red foxes. Scale bars indicate nucleotide substitutions per site

FIGURE 3

Phylogenetic trees displaying the diversity of Bartonella species detected in wild mammals from Italy. The phylogenetic trees for partial gltA (290 bp) (panel a), and ssrA (254 bp) (panel b) sequences from representative known Bartonella isolates were generated by using mega‐x v. 10.0.5 software. Maximum likelihood method with Tamura Nei 3‐parameter substitution model, a proportion of invariable sites and a gamma distribution of rate variation across sites was applied supplying statistical support with subsampling over 1,000 replicates. GenBank accession numbers are provided for reference isolates with the sequence from Brucella abortus (AE017223) used as outgroup. The representative sequences generated in the present study are marked with arrows. Asterisks denote the nucleotide sequences identical to strains retrieved from red foxes. Scale bars indicate nucleotide substitutions per site