Metatranscriptomics reveals the horse gut RNA virome and a viral sharing network with human and domestic animals.

Overview

• This study used metatranscriptome sequencing to explore the variety of RNA viruses present in the gut of horses from different breeds.
• The research revealed a diverse and abundant horse gut RNA virome and discovered viral connections shared between horses, humans, and other domestic animals.

Introduction to RNA Viruses and Horses

• RNA viruses are a unique group of viruses widely found in nature, capable of impacting health globally.
• Monitoring these viruses in livestock is important for disease surveillance and public health.
• Horses are significant companion and working animals, contributing culturally and economically worldwide, yet little was known about their gut RNA viruses before this study.

Methods – Metatranscriptome Sequencing and Bioinformatics Analysis

• The study sampled gut contents from 16 horses encompassing three breeds: Thoroughbred, Akhal-Teke, and Yili horse.
• Metatranscriptome sequencing was performed, a technique that sequences the RNA content of the samples to identify actively transcribed viruses.
• Bioinformatics tools were used to assemble the sequenced data and classify viral genomes by family and type.

Results – Discovery of the Horse Gut RNA Virome

• A total of 497 distinct viral genomes were recovered from the horse gut, spanning 22 different viral families.
• Viruses identified included both double-stranded RNA (dsRNA) and single-stranded RNA (ssRNA) viruses, covering positive- and negative-sense RNA viruses commonly infecting mammals.
• The most abundant RNA viral family detected was Picobirnaviridae, which is known to inhabit mammalian intestines.

Breed-Specific Viral Diversity and Differential Abundance

• Beta diversity analyses showed significant variation in the abundance of RNA viruses across the three horse breeds studied.
• Statistical analysis identified 82 RNA viruses showing significant abundance differences (p < 0.05) between the Akhal-Teke and Yili horse breeds.
• This suggests that breed or related factors such as genetics, diet, or environment may influence the horse gut RNA virome composition.

Comparative Analysis with Other Mammals

• Coverage scores from this study were compared with virome data from other mammals including humans, cows, and sheep.
• Results uncovered a viral sharing network within the intestinal RNA viruses of these species, indicating overlapping or shared viral populations.
• Such sharing suggests potential cross-species transmission or common viral reservoirs in domestic and human environments.

Significance and Future Implications

• This is among the first comprehensive characterizations of the horse gut RNA virome, enriching understanding of virome diversity in an important domestic animal.
• The discovery of viral sharing networks highlights ecological and health connections among horses, humans, and other domestic mammals.
• These insights could guide future surveillance, disease prevention, and One Health approaches integrating animal and human health.
• Further research may investigate viral impacts on horse health and the dynamics of cross-species viral transmission.