# Molecular Screening of Black Flies (Diptera: Simuliidae) for Vector‐Borne Zoonotic Pathogens, South Moravia, Czech Republic

## TL;DR

This study found new Bartonella bacteria in black flies in the Czech Republic, suggesting a potential risk to human and animal health.

## Contribution

The discovery of four new Bartonella spp. variants in black flies is a novel finding in vector-borne disease research.

## Key findings

- Almost all black fly pools tested negative for known arthropod-borne pathogens and parasites.
- Four new Bartonella spp. variants were identified in black flies, showing similarity to human and arthropod-associated bartonellae.
- The study highlights the potential public and veterinary health risks posed by black flies in Europe.

## Abstract

Black flies (Simuliidae) are globally distributed blood‐feeding arthropods and vectors of viral, bacterial, and parasitic pathogens to many animal species, including humans. We investigated the occurrence of selected vector‐borne pathogens in black flies in South Moravia, Czech Republic, and evaluated their possible role in the circulation of vector‐borne pathogens.

A total of 11,600 black flies comprising four species of the genus Simulium, namely Simulium (Boophthora) erythrocephalum (De Geer, 1776), Simulium (Wilhelmia) lineatum (Meigen, 1804), Simulium (Wilhelmia) balcanicum (Enderlein, 1924), and Simulium (Wilhelmia) turgaicum (Rubtsov, 1940) were pooled and screened for the following arthropod‐borne pathogens and parasites endemic in Central Europe: viruses (alphaviruses, bunyaviruses and flaviviruses), bacteria (
Borrelia burgdorferi
sensu lato,
Borrelia miyamotoi
,
Anaplasma phagocytophilum
, Neoehrlichia mikurensis, Bartonella spp., Rickettsia spp.,
Francisella tularensis
,
Coxiella burnetii
, and Brucella spp.), protista (Babesia spp., Encephalitozoon spp. and Enterocytozoon spp.) and filaria (Dirofilaria spp., Setaria spp., and Onchocerca spp.).

Almost all pools were negative for known arthropod‐borne pathogens and parasites. However, four new Bartonella spp. variants were found that share similarity with other bartonellae reported from diverse arthropods and humans. The phylogenetic analysis of Bartonella sequences from Czech black flies provides further evidence about an expanding diversity of Bartonella lineages in arthropods globally, including hematophagous species (e.g., ticks, mosquitoes, and biting flies) and non‐hematophagous species (e.g., bees and ants). These bartonellae have the potential to cause pathogenic infections in humans who are exposed to arthropods carrying these bacteria.

Summing up, this study provides for the very first time valuable data for characterising the risk to public and veterinary health from black flies and the infections they may carry in Europe. Further testing, however, should include a wider geographic, seasonal, and taxonomic range of black flies.

Black flies (Simuliidae) are globally distributed blood‐feeding arthropods and vectors (both mechanical and biological) of viral, bacterial and parasitic pathogens to many animal species, including humans.Four new variants of Bartonella spp. have been found in black flies and show similarities to other Bartonella reported from various arthropods and humans. These bartonellae have the potential to cause pathogenic infections in humans when exposed to vectors carrying these bacteria.This study provides for the first time valuable data to characterise the public and veterinary health risk posed by black flies and the infections they may transmit in Europe.

Black flies (Simuliidae) are globally distributed blood‐feeding arthropods and vectors (both mechanical and biological) of viral, bacterial and parasitic pathogens to many animal species, including humans.

Four new variants of Bartonella spp. have been found in black flies and show similarities to other Bartonella reported from various arthropods and humans. These bartonellae have the potential to cause pathogenic infections in humans when exposed to vectors carrying these bacteria.

This study provides for the first time valuable data to characterise the public and veterinary health risk posed by black flies and the infections they may transmit in Europe.