# Porcine Deltacoronavirus-Related Viruses in House Sparrows

## TL;DR

This study found deltacoronaviruses in house sparrows near pig farms, suggesting possible transmission and evolution of PDCoV.

## Contribution

The study provides new evidence of deltacoronavirus presence in house sparrows and their potential role in PDCoV evolution.

## Key findings

- Deltacoronaviruses were detected in 18% of house sparrow fecal samples near pig farms.
- Genomic analysis showed SpDCoVs are closely related but not direct ancestors of PDCoVs.
- Attempts to isolate SpDCoV in chicken eggs and cell lines were unsuccessful.

## Abstract

Porcine deltacoronavirus (PDCoV) is an emerging enteric pathogen in pigs and a newly recognized zoonotic coronavirus in humans. Genetic analyses suggest that PDCoV originated from avian deltacoronaviruses, with sparrow deltacoronaviruses (SpDCoVs) being the most closely related. House sparrows (Passer domesticus) frequently visit farms and interact directly with pigs in barns, raising the possibility of interspecies transmission. We hypothesized that PDCoV can be transmitted between pigs and house sparrows. To investigate this, 200 house sparrows near Ohio swine farms were sampled and screened for gammacoronaviruses and deltacoronaviruses using RT-PCR targeting the conserved RNA polymerase region. Deltacoronaviruses and gammacoronaviruses were detected in 18.0% (36/200) and 5.5% (11/200) of fecal samples, respectively. Genomic sequence analysis of representative samples revealed that SpDCoVs are closely related to, but not direct ancestors of, PDCoVs. These SpDCoVs appear to be widespread in the U.S. Midwest and may contribute to PDCoV evolution. Attempts to isolate SpDCoV from these samples in embryonated chicken eggs and four cell lines were unsuccessful. Because coronaviruses frequently cross species barriers to cause epidemics and/or pandemics in humans and livestock, these findings underscore the need for ongoing surveillance of deltacoronaviruses in diverse wild animals, livestock, and humans to safeguard public health.