Our new study, published in Pathogens, explores the largely unexplored role of bat flies in the maintenance and potential transmission of viruses. In particular, we investigated whether viruses could persist across generations of bat flies through vertical transmission.
We analyzed 80 bat fly pupae collected from a large Miniopterus schreibersii colony in Hungary using viral metagenomic sequencing. Although several bioinformatic tools initially identified putative viral sequences, detailed sequence-level validation showed that none of these viral assignments could be confirmed.
The results therefore provide no evidence that vertical transmission is a major mechanism maintaining viruses across generations in the investigated bat fly population. However, the findings need to be interpreted cautiously, as the study was based on a relatively small number of pupae collected during a single sampling occasion. Highly divergent or low-abundance viruses may also have remained undetected.
An important outcome of the study was the demonstration of how initial viral assignments in metagenomic datasets can be misleading. Our results highlight the importance of rigorous sequence-level validation, including BLAST-based assessment, read mapping and manual inspection, before putative viral sequences are interpreted as evidence of virus presence.
This work represents a first step toward understanding potential transgenerational viral persistence in bat flies and provides a basis for future studies using broader seasonal and geographic sampling, as well as experimental approaches to investigate virus transmission in bat-ectoparasite systems.
Reference: Láng, L., Kemenesi, G., Novák, J., Lanszki, Z. & Görföl, T. (2026). Viral Metagenomic Analysis of Bat Fly Pupae. Pathogens 15, 950.
Open-access article: https://doi.org/10.3390/pathogens15090950