Molecular evidence of Bartonella spp. in tropical wild birds from the Brazilian Pantanal, the largest wetland in South America

Validation of a High-Throughput Microfluidic Real-Time PCR for the Detection of Vector-Borne Agents in Wild Birds from the Brazilian Pantanal

Despite numerous studies on haemosporidians in wild birds from Brazil, the presence of other vector-borne agents (VBA) such as Anaplasma spp., Bartonella spp., and Onchocercidae filariids in avian hosts remains largely unknown. The low occurrence of these VBAs might be due to the low sensitivity of traditional molecular techniques. The microfluidic real-time PCR assay, known for its high sensitivity, has emerged as a promising method to detect and study the occurrence and diversity of VBAs in both arthropod vectors and vertebrate hosts. To validate previously and standardize newly designed microfluidic real-time PCR protocols, selected positive avian blood DNA samples for Anaplasma spp., Bartonella spp., haemosporidians, and filariids were used. The molecular occurrence rates for the selected VBAs were 18.2% for Anaplasma spp., 0.36% for Bartonella spp., 6.2% for Plasmodium spp., 4.7% for Haemoproteus spp., and 6.5% for Onchocercidae filariids. The Plasmodium spp. cytB sequence detected in a Volatinia jacarina clustered with Plasmodium tejerai, whereas the Haemoproteus spp. cytB sequence detected in a Columbina squamata clustered with Haemoproteus columbae. While Onchocercidae filariid cox-1 sequences were detected in specimens of Ramphocelus carbo, Turdus amaurocalinus and Synallaxis albilora grouped with Aproctella spp., one sequence detected in R. carbo was ancestral to the clade comprising Splendidofilaria spp. and Eufilaria spp. High-throughput microfluidic real-time PCR assay can be used for screening VBAs in avian hosts from South America, but new primers/probe sets should be designed for VBA genotypes present in Brazil.

Molecular evidence of Bartonella spp. in biting midges of the genus Culicoides Latreille (Diptera: Ceratopogonidae) from Brazil

Bartonella spp. are typical vector-borne pathogens, whose transmission has been primarily associated with a wide variety of hematophagous arthropods. These bacteria are responsible for several clinical syndromes in both humans and animals. The present study aimed to investigate the occurrence and molecular identity of Bartonella spp. in 345 specimens of Culicoides Latreille from the Brazilian Amazon. Out of 345 Culicoides specimens collected in the Amazon National Park, state of Pará, northern Brazil, 86.7 % (299/345) were positive for the endogenous cytochrome c oxidase subunit 1 gene. We detected a 24 % (72/299) prevalence rate for Bartonella spp. using a quantitative real-time PCR targeting the 16S-23S rRNA internal transcribed spacer (ITS) region. Culicoides foxi was statistically more associated with Bartonella positivity when compared to C. hylas and C. leopoldoi. Culicoides specimens collected at the ground level were more associated with positivity for Bartonella spp. when compared to those collected at the canopy. Further molecular characterization was performed using conventional PCR assays targeting seven molecular markers (nuoG, gltA, groEL, ftsZ, rpoB, pap31, and ribC). The BLASTn analysis revealed four gltA sequences with 99.72-100 % identity to Bartonella bovis previously detected in cattle from Brazil. One ribC sequence showed 100 % identity to Bartonella henselae previously detected in a cat from Germany. Six pap31 sequences showed 90-91 % identity to a Bartonella sp. sequence previously detected in a bat (Carollia perspicillata) from Brazil. This study represents the first molecular evidence of Bartonella spp. DNA in biting midges and contributes to understanding their role in the epidemiological cycles of these agents.

First molecular detection of Bartonella spp. in two chewing louse species (Amblycera: Menoponidae and Ischnocera: Philopteridae) parasitizing Calonectris borealis (Cory, 1881) (Procellariiformes: Procellariidae)

Procellariidae is the most diverse family of the order Procellariiformes, with 13 genera and about 90 species of seabirds. The genus Calonectris is represented by three species in the Atlantic Ocean. Bartonella spp. is a globally distributed bacterium primarily affecting mammals, with transmission through hematophagous arthropod vectors. Recent studies have found Bartonella in non-mammals like birds and turtles, prompting the present study to explore the potential role of chewing lice in its transmission. Here, we report two different Bartonella genotypes in each lice species identified: one showing genetic relatedness to Bartonella vinsonii berkhoffii, and another one to Bartonella sp. from Neotropical bats. In addition, we report, for the first time, a case of co-infestation of chewing lice of the species Austromenopon echinatum (Piaget) and Halipeurus abnormis Edwards, found the carcass of Calonectris borealis studied. Our findings corroborate recent studies that demonstrated that bartonellae are no longer restricted to mammals and their ectoparasites.

Uropygial gland microbiota of nearctic-neotropical migrants vary with season and migration distance

Symbiotic microbiota are important drivers of host behaviour, health, and fitness. While most studies focus on humans, model organisms, and domestic or economically important species, research investigating the role of host microbiota in wild populations is rapidly accumulating. Most studies focus on the gut microbiota; however, skin and other glandular microbiota also play an important role in shaping traits that may impact host fitness. The uropygial gland is an important source of chemical cues and harbours diverse microbes that could mediate chemical communication in birds, so determining the factors most important in shaping host microbiota should improve our understanding of microbially-mediated chemical communication. Hypothesizing that temporal, geographic, and taxonomic effects influence host microbiota, we evaluated the effects of season, migration distance, and taxonomy on the uropygial gland microbiota of 18 passerine species from 11 families. By sampling 473 birds at a single stopover location during spring and fall migration and using 16S rRNA sequencing, we demonstrate that season, followed by migration distance, had the strongest influence on uropygial gland microbial community composition. While statistically significant, taxonomic family and species had only weak effects on gland microbiota. Given that temporal effects on gland microbiota were nearly ubiquitous among the species we tested, determining the consequences of and mechanisms driving this seasonal variation are important next steps.

Molecular Survey on the Occurrence of Tick-Borne Bacteria in Wild Birds from Central Italy

Birds are known to be carriers of ticks infected by tick-borne pathogens, including bacteria. However, not many studies have been carried out on avian tissues to detect these agents. The aim of the present survey was to investigate, using PCR, the presence of Anaplasma phagocytophilum, Bartonella spp., Borrelia burgdorferi sensu lato, Chlamydia psittaci, Coxiella burnetii, Ehrlichia canis, Francisella tularensis, and Rickettsia spp. in the spleens collected from 300 wild birds of different orders and species from Central Italy. A total of 53 (17.67%) samples were PCR positive for at least one investigated pathogen. One (0.33%) bird was positive for Bartonella spp., five (1.67%) birds were positive for C. burnetii, eleven (3.67%) for B. burgdorferi s.l., and thirty-six (12%) for C. psittaci. No coinfection was detected. All samples were negative for A. phagocytophilum, E. canis, F. tularensis, and Rickettsia spp. The findings showed that wild birds may harbor different zoonotic tick-borne bacteria; therefore, they can contribute to the diffusion of these agents.

Novel Tick-Borne Anaplasmataceae Genotypes in Tropical Birds from the Brazilian Pantanal Wetland

Despite numerous reports of Anaplasmataceae agents in mammals worldwide, few studies have investigated their occurrence in birds. The present study aimed to investigate the occurrence and molecular identity of Anaplasmataceae agents in birds from the Pantanal wetland, Brazil. Blood samples were collected from 93 different species. After DNA extraction, samples positive for the avian β-actin gene were subjected to both a multiplex quantitative real-time (q)PCR for Anaplasma and Ehrlichia targeting the groEL gene and to a conventional PCR for Anaplasmataceae agents targeting the 16S rRNA gene. As a result, 37 (7.4%) birds were positive for Anaplasma spp. and 4 (0.8%) for Ehrlichia spp. in the qPCR assay; additionally, 13 (2.6%) were positive for Anaplasmataceae agents in the PCR targeting the 16S rRNA gene. The Ehrlichia 16S rRNA sequences detected in Arundinicola leucocephala, Ramphocelus carbo, and Elaenia albiceps were positioned closely to Ehrlichia sp. Magellanica. Ehrlichia dsb sequences detected in Agelasticus cyanopus and Basileuterus flaveolus grouped with Ehrlichia minasensis. The 16S rRNA genotypes detected in Crax fasciolata, Pitangus sulphuratus and Furnarius leucopus grouped with Candidatus Allocryptoplasma. The 23S-5S genotypes detected in C. fasciolata, Basileuterus flaveolus, and Saltator coerulescens were related to Anaplasma phagocytophilum. In conclusion, novel genotypes of Anaplasma, Ehrlichia, and Candidatus Allocryptoplasma were detected in birds from the Pantanal wetland.