# Comparative analysis of fecal DNA viromes in Large-billed crows and Northern ravens reveals diverse viral profiles

## TL;DR

This study compares the viral DNA in the feces of two scavenger bird species, finding similar viral diversity and composition despite differences in dominant virus families.

## Contribution

The study provides a comparative analysis of fecal DNA viromes in two scavenger bird species using metagenomics.

## Key findings

- Northern ravens had higher proportions of Parvoviridae and Microviridae compared to Large-billed crows.
- No significant differences in viral diversity were found between the two species using Richness, Shannon, and Simpson indices.
- Both species showed similar KEGG-enriched pathways related to metabolism and genetic processing.

## Abstract

As facultative scavenger birds, crows carry various parasites, viruses, and bacteria, making them significant infection hosts and transmission vectors. In this study, we employed viral metagenomics to enrich viral particles from three fecal samples of the Northern ravens (Corvus corax) and four fecal samples of the Large-billed crows (Corvus macrorhynchos). Viral DNA was then extracted, and seven sequencing libraries were constructed. The composition and characteristics of the DNA viromes in the feces of these two facultative scavenging bird species were analyzed using the Illumina NovaSeq platform (PE150 mode). The results showed that the fecal DNA viruses carried by Northern ravens mainly belonged to Parvoviridae (31.49%), Caudoviricetes_Unclassified (21.91%), Microviridae (21.57%), and Genomoviridae (18.2%), while those carried by Large-billed crows were predominantly Genomoviridae (29.7%), Parvoviridae (26.15%), and Caudoviricetes_Unclassified (22.15%). Diversity analysis using Richness, Shannon, and Simpson indices showed no significant differences in viral composition between the two crow species. Additionally, principal coordinate analysis (PCoA) (F = 1.079, P = 0.155) and non-metric multidimensional scaling (NMDS) (F = 1.079, P = 0.154) analyses demonstrated no distinct separation between the two groups. Moreover, the KEGG-enriched pathways in both crow species were primarily associated with metabolic and genetic information processing functions. The selection of the Large-billed crows and Northern ravens in this study was based on their widespread distribution, close association with human settlements, and distinctive scavenging behavior. Comparative analysis of the diversity and composition of their DNA viral communities offers a basis for evaluating the zoonotic risks associated with these scavenger birds.