Gross and histopathological evaluation of tissues following infection of 8-week-old piglets with the highly virulent porcine reproductive and respiratory syndrome virus 1 (PRRSV-1) Lleida 029_22 strain

(A) Representative images of lung tissues showing healthy and progressively severe pulmonary lesions. (B) Histology scores for each pig, correlated with their time of death. (C) Histology scores by tissue type for all intranasally (IN)-infected pigs and negative controls that survived until 63 days post infection (dpi). Data are presented as mean ± SD.