Association Between PRRSV ORF5 Genetic Distance and Differences in Space, Time, Ownership and Animal Sources Among...

Area of Science:

• Veterinary Virology
• Epidemiology
• Population Genetics

Background:

• Porcine reproductive and respiratory syndrome virus (PRRSV) poses a significant threat to the swine industry.
• Understanding the factors influencing PRRSV genetic diversity is crucial for effective disease control strategies.

Purpose of the Study:

• To investigate the associations between PRRSV genetic distance and spatial, temporal, ownership, and animal source distances in Ontario swine herds.
• To identify key network factors driving PRRSV genetic variation and spread.

Main Methods:

• Analysis of 438 PRRSV isolates' sequence data from September 2004 to August 2007.
• Generation of sequence, spatial, temporal, and network distance matrices.
• Application of Mantel tests and multivariable linear-mixed models with random permutations for statistical analysis.

Main Results:

• A weak positive correlation was found between PRRSV sequence distance and geographic distance (r=0.11, P=0.001) and temporal distance (r=0.03, P=0.03).
• Spatial correlation of PRRSV was observed up to approximately 30 km.
• Ownership (P<0.001) and gilt supplier networks (P<0.001) exhibited the strongest association with PRRSV genetic distance.

Conclusions:

• While spatial and temporal proximity have minor influences, herd ownership and gilt supplier networks are critical drivers of PRRSV genetic distance and spread.
• Further investigation into these network structures is essential for targeted disease management interventions.