Serovar 13 Glaesserella parasuis strain shows marked pathogenicity in piglet challenge model

A clinical isolate of Glaesserella parasuis serovar 13, recovered from the lung of a piglet with severe systemic disease, has been shown to cause dose-dependent mortality in an experimental piglet challenge model, according to a study published in BMC Microbiology on 28 October 2026.

G. parasuis is an important swine pathogen that causes Glässer’s disease, a systemic condition associated with polyserositis, arthritis, meningitis, and pneumonia. Serovar 13 is generally considered highly pathogenic and has been linked to severe clinical disease in pigs, but integrated evidence on its experimental pathogenicity and complete genomic characteristics has remained limited.

The research team, led by Qianming Zhao and Jianchao Wei, characterized strain W2 by combining a piglet challenge model, whole-genome sequencing, and comparative genomic analysis. The strain was a clinical isolate recovered from the lung of a piglet with severe systemic disease.

In the challenge experiments, W2 caused dose-dependent mortality after intraperitoneal challenge, disseminated to multiple tissues and body fluids, and induced dose-associated pulmonary injury. The authors describe these findings as indicating marked pathogenic effects in this intraperitoneal challenge model.

Sequencing revealed that W2 carries a complete circular chromosome of 2.36 megabases with no detectable plasmid replicons, and taxonomic analyses confirmed its placement within G. parasuis.

Genome annotation identified multiple putative virulence-associated homologs, mainly related to immune modulation, nutrient acquisition, adhesion, stress adaptation, and surface structure remodeling. Predicted prophage-like regions, genomic islands, and CRISPR array-like loci further suggested genomic plasticity in the strain.

Antimicrobial resistance screening identified resistance-associated homologs but no definitive acquired resistance genes, according to the study results.

The authors conclude that W2 is a serovar 13 clinical isolate that exhibited marked pathogenic effects in the piglet intraperitoneal challenge model, while genome analysis identified multiple putative virulence-associated features whose contributions to the observed phenotype remain to be established.

The findings add genome-informed context to a serovar that has long been associated with severe disease in pigs, though the study’s conclusions are limited to the intraperitoneal challenge model and the specific clinical isolate examined.

Subject of Research: Pathogenicity and genomic virulence features of Glaesserella parasuis serovar 13 in piglets

Article Title: Pathogenicity and genome-informed virulence features of Glaesserella parasuis serovar 13 in piglets

Article References: Zhao, Q., Pang, L., Li, B., Liu, K., Li, Z., Shao, D., Qiu, Y., Ma, Z., Zhang, H., & Wei, J. (2026). Pathogenicity and genome-informed virulence features of Glaesserella parasuis serovar 13 in piglets. BMC Microbiology. https://doi.org/10.1186/s12866-026-05845-4

Image Credits: AI Generated

DOI: 10.1186/s12866-026-05845-4

Keywords: Glaesserella parasuis, serovar 13, piglets, Glasser's disease, virulence, whole-genome sequencing, challenge model, swine pathogen, genomic islands, CRISPR, Pathogenicity, genome-informed