Genetic variability of encephalomyocarditis virus (EMCV) isolates

Area of Science:

• Veterinary Virology
• Molecular Epidemiology
• Pork Production

Background:

• Encephalomyocarditis virus (EMCV) causes significant disease in pigs, with clinical manifestations varying across Europe since 1986.
• Understanding EMCV genetic variability is crucial for disease management and control.

Purpose of the Study:

• To molecularly characterize European EMCV field isolates.
• To investigate the relationship between EMCV genetic diversity and observed clinical pictures in pigs.
• To assess the impact of in vivo and in vitro passaging on EMCV virulence and attenuation.

Main Methods:

• Molecular characterization of EMCV field isolates from different European regions.
• Sequencing of targeted genomic regions: poly(C) tract, 5'-UTR, Leader gene, capsid coding region, 2A gene, 3D polymerase gene, and 3'-UTR.
• Analysis of a virulent field isolate subjected to serial in vivo and in vitro passaging to evaluate attenuation.

Main Results:

• No direct correlation was established between EMCV genotype and specific clinical diseases (e.g., myocarditis, reproductive failure).
• Both genetically diverse and similar EMCV isolates could cause varied clinical presentations.
• The European isolate with the highest genetic divergence induced a more complex clinical picture.
• In vitro passaging led to EMCV attenuation, as confirmed by animal experiments.

Conclusions:

• EMCV clinical presentation in pigs is not solely determined by genetic makeup, indicating complex host-pathogen interactions.
• EMCV is an emerging disease in Europe with diverse clinical manifestations and pathogenicity.
• EMCV's adaptability and broad host range, including primates, highlight its significance as a potential pathogen in xenotransplantation.