On reproductive and respiratory syndrome virus dissemination across pig production systems in the United States

Manuel Jara; David A. Rasmussen; Cesar A. Corzo; Gustavo Machado

The results of PRRSv ancestral reconstruction showed that the most likely center of origin was production The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.09.034181 doi: bioRxiv preprint origin was a sow farm (RSPP = 0.47), followed by an almost equal probability for origins in finisher farm 207 (RSPP = 0.27) and nursery farm (RSPP = 0.26), the boar stud farms were negligible (RSPP < 0.01) (Fig. 208 3A). In recent years, there was an evident increase in the proportion of PRRSv positive finisher farms, 209 reaching a similar level of representation than sow farms for some clusters (Fig. 3A) . SkyGrid plot 210 revealed a relatively constant trend of relative genetic diversity until ~2011, showing a linear increase in 211 population size, which reached its highest levels ~2016 (Fig. 3B) . We observed a similar trend when we 212 analyzed all systems together (Fig. 3B) , 2015 and 2018 were the years with more samples sent to be 213 sequenced (Fig. 3B) . 214