Molecular pathogen screening of louse flies (Diptera: Hippoboscidae) from domestic and wild ruminants in Austria

Abstract

Background Hippoboscid flies (Diptera: Hippoboscidae), also known as louse flies or keds, are obligate blood-sucking ectoparasites of animals, and accidentally of humans. The potential role of hippoboscids as vectors of human and veterinary pathogens is being increasingly investigated, but the presence and distribution of infectious agents in louse flies is still unknown in parts of Europe. Here, we report the use of molecular genetics to detect and characterize vector-borne pathogens in hippoboscid flies infesting domestic and wild animals in Austria. Methods Louse flies were collected from naturally infested cattle (n = 25), sheep (n = 3), and red deer (n = 12) across Austria between 2015 and 2019. Individual insects were morphologically identified to species level and subjected to DNA extraction for molecular pathogen screening and barcoding. Genomic DNA from each louse fly was screened for Borrelia spp., Bartonella spp., Trypanosomatida, Anaplasmataceae, Filarioidea and Piroplasmida. Obtained sequences of Trypanosomatida and Bartonella spp. were further characterized by phylogenetic and haplotype networking analyses. Results A total of 282 hippoboscid flies corresponding to three species were identified: Hippobosca equina (n = 62) collected from cattle, Melophagus ovinus (n = 100) from sheep and Lipoptena cervi (n = 120) from red deer (Cervus elaphus). Molecular screening revealed pathogen DNA in 54.3% of hippoboscids, including infections with single (63.39%), two (30.71%) and up to three (5.90%) distinct pathogens in the same individual. Bartonella DNA was detected in 36.9% of the louse flies. Lipoptena cervi were infected with 10 distinct and previously unreported Bartonella sp. haplotypes, some closely associated with strains of zoonotic potential. DNA of trypanosomatids was identified in 34% of hippoboscids, including the first description of Trypanosoma sp. in H. equina. Anaplasmataceae DNA (Wolbachia spp.) was detected only in M. ovinus (16%), while < 1% of the louse flies were positive for Borrelia spp. and Filarioidea. All hippoboscids were negative for Piroplasmida. Conclusions Molecular genetic screening confirmed the presence of several pathogens in hippoboscids infesting domestic and wild ruminants in Austria, including novel pathogen haplotypes of zoonotic potential (e.g. Bartonella spp.) and the first report of Trypanosoma sp. in H. equina, suggesting a potential role of this louse fly as vector of animal trypanosomatids. Experimental transmission studies and expanded monitoring of hippoboscid flies and hippoboscid-associated pathogens are warranted to clarify the competence of these ectoparasites as vectors of infectious agents in a One-Health context. Graphical Abstract

Global Mapping and Visualization Analysis of One Health Knowledge in the COVID-19 Context

“…The search interval remained open from its start and concluded upon data retrieval. The most commonly utilized One Health terms 10 , 36 , 37 and those associated with COVID-19 2 , 6 , 29 , 38 were incorporated into the “Title-Abstract” section within the Scopus database. It is suggested that publications engaged in One Health and COVID-19 research (conceptually, methodologically, and/or empirically) would, at a minimum, refer to One Health and COVID-19 terms within their title and/or abstract.…”

Contributions to our knowledge on avian louse flies (Hippoboscidae: Ornithomyinae) with the first European record of the African species Ornithoctona laticornis

“…Research on hippoboscids is flourishing nowadays, i.e. with investigations focusing on their ecology, evolution, and potential role in the transmission of pathogens [ 3 , 9 – 14 ].…”

Relevant Brachycera (Excluding Oestroidea) for Horses in Veterinary Medicine: A Systematic Review

“…Hippoboscidae, also known as louse flies, are bloodsucking flies. Hippobosca equina is the most common specie to parasitize Equidae [15,18]. Additionally, horses are discussed to be a facultative host of Lipoptena cervi [19].…”

“…Hippobosca equina and L. cervi are considered potential vectors for bacterial agents such as Bartonella spp. [18,19].…”