# Molecular Characterization of Avulaviruses Isolated from Mallard Ducks in Moscow in 2008–2024

## TL;DR

This study characterizes avulaviruses from mallard ducks in Moscow, revealing their genetic diversity and low pathogenicity.

## Contribution

The study provides new insights into the genetic diversity and phylogenetic distribution of avulaviruses in wild mallard ducks in Moscow.

## Key findings

- Thirteen avulaviruses were isolated from mallard ducks between 2008 and 2024.
- Phylogenetic analysis showed AOAV-1 isolates belong to genotype 1 of class II and APMV-4 isolates to the Eurasian subgenotype of genotype 1.
- All isolates were found to be non-pathogenic based on F protein cleavage site analysis.

## Abstract

Waterfowl birds serve as reservoirs and vectors for a range of pathogens, including avulaviruses. The most well-known group of avulaviruses comprises Newcastle disease viruses, or Avian orthoavulavirus 1 (AOAV-1), which cause diseases of varying severity in more than 200 bird species. Between 2008 and 2024, 13 avulaviruses belonging to 2 species were isolated and partially sequenced from fecal samples of mallard ducks (Anas platyrhynchos). The isolated viruses belong to phylogenetic lineages widely distributed across Eurasia and are not highly pathogenic. The data obtained in this study reflect the genetic diversity of avulaviruses disseminated by mallards along migratory routes passing through Moscow.

Species of the orders Charadriiformes and Anseriformes serve as the primary long-distance disseminators of various avulaviruses. The most economically significant among them is Newcastle disease virus (NDV), or Avian orthoavulavirus 1 (AOAV-1), which causes diseases of varying severity in both domestic and wild birds. Other avulaviruses have been studied to a much lesser extent, and for most of them, only single isolates are known, which does not allow a comprehensive assessment of their potential threat. To evaluate the biological diversity and potential risks posed by avian paramyxoviruses spread by wild waterfowl during autumn migration, fecal samples from mallards (Anas platyrhynchos) (n = 3604) were collected at water bodies in Moscow and the Moscow Region between 2008 and 2024. From these samples, AOAV-1 (n = 4) and Avian paraavulavirus 4 (APMV-4) (n = 9) were isolated and partially sequenced. Phylogenetic analysis revealed that all AOAV-1 isolates belong to genotype 1 of class II, while all APMV-4 isolates belong to the Eurasian subgenotype of genotype 1. Analysis of the F protein cleavage site motif indicated conformity with the consensus sequences characteristic of lentogenic and non-pathogenic avian paramyxoviruses in all isolates.