Estimating sampling and laboratory capacity for a simulated African swine fever outbreak in the United States

Abstract

The introduction of African swine fever virus (ASFV) into uninfected countries can impact economic and animal welfare. Rapid detection and control of the outbreak contribute to successful eradication and promote business continuity. We developed a model to determine the number of samples, sample collectors, laboratory capacity, and processing times following an ASFV introduction into the U.S. We simulated the spread of ASFV in one densely populated swine region, generating a median of 27 (range = 1-68) outbreaks in 150 days, resulting 616 (range = 1-15,011) sampling events with a total of 3,068 barns (range = 7-69,118) sampled. We calculated the total sample collectors needed, considering daily working hours, sampling and driving time, and laboratory capabilities with and without blood sample pooling. Samples included 31 blood samples and five oral fluid samples per barn, which equal 84,830 (range = 52-2,066,831) and 14,195 (range = 10-345,590) blood and oral fluid samples, respectively. The median number of sample collectors needed to prevent sampling delay varied from 136 to 367 and, in the worst epidemic scenarios, from 833 to 3,115. Notably, excluding downtime-which prevented the sampler from visiting additional farms for 24 or 72 hours-reduced the number of sample collectors needed between 28% and 75%, while switching from blood to oral fluid samples reduced this number between 47% and 75%. At a laboratory processing daily capacity of 1,000 samples, the median days for sample processing without pooling were 92 days, with a maximum of 5.7 years. We demonstrated a need to redistribute 10,062 (range = 2-67,940) unprocessed samples daily to other laboratories to prevent processing delays. Our study addresses the challenge of efficiently organizing resources for managing a potential ASFV outbreak, providing information about the number of sample collectors and laboratory capacity needed for one densely populated swine region in the U.S.