Expanding our view of Bartonella and its hosts: Bartonella in nest ectoparasites and their migratory avian hosts

Heather M Williams,Katharina Dittmar

doi:10.1186/s13071-020-3896-7

Heather M Williams, Katharina Dittmar

Open Access

https://doi.org/10.1186/s13071-020-3896-7

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Abstract

BackgroundBartonella is a genus of Gram-negative facultative intracellular Alphaproteobacteria of public health importance. Although they are known to mainly infect mammalian hosts with some blood-feeding arthropods having been confirmed as vectors, there is some evidence of Bartonella association with non-mammalian hosts including birds.MethodsHere we used high-throughput sequencing of 16S rRNA and Sanger sequencing of the citrate synthase (gltA) genes to test for the presence of Bartonellaceae in the blood of three migratory cavity nesting bird species, purple martins (Progne subis), tree swallows (Tachycineta bicolor) and eastern bluebirds (Sialia sialis) and their most prevalent and abundant nest ectoparasites, Dermanyssus prognephilus (mite), Ceratophyllus idius (flea) and Protocalliphora sialia (bird blow fly larva). We constructed maximum likelihood phylogenetic trees to verify the placement of the resulting sequences in the Bartonellaceae.ResultsWe found evidence of Bartonella in all three bird species and all three arthropod species tested. We report multiple instances of identical Bartonella sequences in both birds and parasites, leading to the likely hypothesis that these ectoparasites are potential vectors of Bartonella. Our phylogenetic analysis suggests that ‘avian Bartonella’ may form its own sub-clade within the genus Bartonella.ConclusionsTo the best of our knowledge, we provide the first confirmation of overlapping Bartonella strains among bird hosts and various species of nest-associated ectoparasites from the same system, suggesting a possible Bartonella host–vector relationship between these arthropods and a non-mammalian host. Our study adds to the growing appreciation of the Bartonellaceae as a phylogenetically diverse group with a wide range of hosts.

Highlights

Bartonella is a genus of Gram-negative facultative intracellular Alphaproteobacteria of public health importance
Bartonella sequences from 16S rRNA sequencing Sequences assigned to Bartonella were found in all three nest-associated ectoparasite species and all three cavitynesting bird species (Additional file 5: Table S5)
Ectoparasite samples were comprised of multiple individuals (8 for D. prognephilus, 4 for C. idius and 2 for P. sialia) which complicates the calculation of prevalence

Summary

Introduction

Bartonella is a genus of Gram-negative facultative intracellular Alphaproteobacteria of public health importance. They are known to mainly infect mammalian hosts with some blood-feeding arthropods having been confirmed as vectors, there is some evidence of Bartonella association with non-mammalian hosts including birds. Williams and Dittmar P arasites Vectors (2020) 13:13 been isolated by two studies in non-mammalian vertebrate hosts One study found it in loggerhead sea turtles (Caretta caretta) [4] and another study found B. henselae and B. koehlerae in blood samples from North American wild birds [northern mockingbirds (Mimus polyglottos), red-winged blackbirds (Agelaius phoeniceus), red-bellied woodpeckers (Melanerpes carolinus) and common loons (Gavia immer)] [5]. This study did not achieve a high taxonomic resolution on these bacteria (leading the authors to conservatively label it as ‘Bartonella-like’ bacteria), this could be of high commercial and animal-health interest as D. gallinae has a worldwide distribution with over 80% of poultry farms reporting infestations [9]

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