In this work, we describe the first Leishmania-infecting leishbunyavirus-the first virus other than Leishmania RNA virus (LRV) found in trypanosomatid parasites. Its host is Leishmaniamartiniquensis, a human pathogen causing infections with a wide range of manifestations from asymptomatic to severe visceral disease. This virus (LmarLBV1) possesses many characteristic features of leishbunyaviruses, such as tripartite organization of its RNA genome, with ORFs encoding RNA-dependent RNA polymerase, surface glycoprotein, and nucleoprotein on L, M, and S segments, respectively. Our phylogenetic analyses suggest that LmarLBV1 originated from leishbunyaviruses of monoxenous trypanosomatids and, probably, is a result of genomic re-assortment. The LmarLBV1 facilitates parasites' infectivity in vitro in primary murine macrophages model. The discovery of a virus in L.martiniquensis poses the question of whether it influences pathogenicity of this parasite in vivo, similarly to the LRV in other Leishmania species.

• Keywords
• Bunyavirales, Leishmania martiniquensis, leishbunyavirus,
• MeSH
• Phylogeny * MeSH
• Genome, Viral * MeSH
• Leishmania pathogenicity   virology   MeSH
• Macrophages parasitology   MeSH
• Mice MeSH
• Open Reading Frames MeSH
• Reassortant Viruses MeSH
• RNA-Dependent RNA Polymerase MeSH
• RNA Viruses classification   genetics   MeSH
• High-Throughput Nucleotide Sequencing MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• RNA-Dependent RNA Polymerase MeSH

Trypanosomatid flagellates have not been studied in Austria in any detail. In this study, specific nested PCR, targeted on the ribosomal small subunit, was used to determine the occurrence and diversity of trypanosomatids in wild-caught mosquitoes sampled across Eastern Austria in the years 2014-2015. We collected a total of 29,975 mosquitoes of 19 species divided in 1680 pools. Of these, 298 (17.7%), representing 12 different mosquito species, were positive for trypanosomatid DNA. In total, seven trypanosomatid spp. were identified (three Trypanosoma, three Crithidia and one Herpetomonas species), with the highest parasite species diversity found in the mosquito host Coquillettidia richiardii. The most frequent parasite species belonged to the mammalian Trypanosoma theileri/cervi species complex (found in 105 pools; 6.3%). The avian species T. culicavium (found in 69 pools; 4.1%) was only detected in mosquitoes of the genus Culex, which corresponds to their preference for avian hosts. Monoxenous trypanosomatids of the genus Crithidia and Herpetomonas were found in 20 (1.3%) mosquito pools. One third (n = 98) of the trypanosomatid positive mosquito pools carried more than one parasite species. This is the first large scale study of trypanosomatid parasites in Austrian mosquitoes and our results are valuable in providing an overview of the diversity of these parasites in Austria.

• MeSH
• Biodiversity MeSH
• Culicidae parasitology   MeSH
• Phylogeny MeSH
• DNA, Protozoan MeSH
• DNA, Ribosomal MeSH
• Sequence Analysis, DNA MeSH
• Trypanosoma classification   genetics   MeSH
• Trypanosomiasis parasitology   transmission   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Austria MeSH
• Names of Substances
• DNA, Protozoan MeSH
• DNA, Ribosomal MeSH

BACKGROUND: Although avian trypanosomes are widespread parasites, the knowledge of their vectors is still incomplete. Despite biting midges (Diptera: Ceratopogonidae) are considered as potential vectors of avian trypanosomes, their role in transmission has not been satisfactorily elucidated. Our aim was to clarify the potential of biting midges to sustain the development of avian trypanosomes by testing their susceptibility to different strains of avian trypanosomes experimentally. Moreover, we screened biting midges for natural infections in the wild. RESULTS: Laboratory-bred biting midges Culicoides nubeculosus were highly susceptible to trypanosomes from the Trypanosoma bennetti and T. avium clades. Infection rates reached 100%, heavy infections developed in 55-87% of blood-fed females. Parasite stages from the insect gut were infective for birds. Moreover, midges could be infected after feeding on a trypanosome-positive bird. Avian trypanosomes can thus complete their cycle in birds and biting midges. Furthermore, we succeeded to find infected blood meal-free biting midges in the wild. CONCLUSIONS: Biting midges are probable vectors of avian trypanosomes belonging to T. bennetti group. Midges are highly susceptible to artificial infections, can be infected after feeding on birds, and T. bennetti-infected biting midges (Culicoides spp.) have been found in nature. Moreover, midges can be used as model hosts producing metacyclic avian trypanosome stages infective for avian hosts.

• Keywords
• Avian parasite, Culicoides nubeculosus, Host specificity, Life-cycle, Transmission, Trypanosoma avium, Trypanosoma bennetti, Trypanosoma culicavium,
• MeSH
• Ceratopogonidae anatomy & histology   parasitology   MeSH
• Gastrointestinal Tract parasitology   MeSH
• Insect Vectors parasitology   MeSH
• Host Specificity MeSH
• Canaries parasitology   MeSH
• Microscopy, Electron, Scanning MeSH
• Bird Diseases parasitology   transmission   MeSH
• Polymerase Chain Reaction MeSH
• Birds parasitology   MeSH
• Trypanosoma classification   genetics   physiology   ultrastructure   MeSH
• Trypanosomiasis diagnosis   parasitology   transmission   veterinary   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH