By Jean-Paul MacDonald
Researchers from North Carolina State University have delved into the risks and potential impact of an African swine fever (ASF) outbreak in the southeastern U.S. Utilizing a sophisticated computer model, they have shed light on the transmission routes and evaluated the effectiveness of existing response plans, providing valuable insights into the country's readiness to combat this highly contagious swine disease.
ASF poses a significant threat to pigs, with a mortality rate that can reach a devastating 100%. Complicating matters further, infected pigs may not exhibit symptoms before succumbing to the disease, creating opportunities for the virus to silently spread. The projected cost of a potential ASF outbreak in the U.S. has been estimated at a staggering $80 billion.
The researchers employed an epidemiological model called PigSpread, which meticulously examined six different transmission routes, including between-farm swine movements, vehicle movements, and local spread. Drawing from a vast dataset of 2,294 swine farms in the southeastern U.S., the model captured the complexity of ASF transmission dynamics.
Their simulations revealed that between-farm movements accounted for a substantial 71% of disease transmissions, with local spread and vehicular transmission contributing approximately 14% each. Remarkably, vehicular transmission emerged as a crucial route for disease spread, emphasizing the need for a deeper understanding of this aspect.
Implementing a combination of control strategies, including quarantine, depopulation, movement restrictions, contact tracing, and enhanced surveillance, exhibited a positive impact in curbing the outbreak. Simulations incorporating these interventions demonstrated an average reduction of up to 79% in secondary infections within the 140-day timeframe. Encouragingly, approximately 29% of simulations with all control strategies implemented showed no further affected farms during that period.
Despite these promising results, the researchers caution that more investigations are required to refine control measures and fully comprehend the scope of effective intervention. Furthermore, they highlight that the duration of an epidemic may surpass the 140-day timeframe, underscoring the need for sustained efforts and a long-term approach to tackling ASF.