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In a new study, researchers from North Carolina State University used a computer model to understand how African swine fever (ASF) might spread among swine farms in the southeastern U.S. – and examined the effectiveness of existing response plans.
The researchers used an epidemiological model, called PigSpread, to look at the different ways a potential outbreak in the southeastern U.S. could unfold. The PigSpread model evaluates six transmission routes including between-farm swine movements, vehicle movements, and local spread, to model the dissemination of ASF.
The infection data used in this model came from the Morrison Swine Health Monitoring Project. Location, production type, capacity, between-farm swine movements and vehicle movement data from 2,294 swine farms in the southeastern U.S. was collected from collaborating swine production companies and was also fed into the model.
The researchers simulated the course of infection both with and without control strategies, varying the starting point of the outbreak. Overall, they ran approximately 230,000 different simulations, with each simulation occurring over a 140-day time period. They then averaged the results.
Between-farm movements accounted for 71% of disease transmissions in the model, with local spread and vehicular transmission both contributing about 14% each.
The model also showed that control actions, specifically a combination of quarantine, depopulation, movement restrictions, contact tracing, and enhanced surveillance, did have an impact. In simulations where these actions were implemented, secondary infections were reduced by up to 79% on average within the 140-day time frame. Twenty-nine percent of the simulations where all control strategies were implemented saw no more affected farms within that time period.
June 22, 2023/ NC State University/ United States.
https://news.ncsu.edu
