Tissue reaction to Fasciola gigantica in rabbits after treatment with rafoxanide

The tissue reaction to immature Fasciola gigantica was investigated in rabbits experimentally infected with 60 or 100 metacercariae. The rabbits were killed 1, 2, 4, 7, and 14 days after treatment, or 14 days after infection.The histopathological changes of the liver were similar in rabbits killed 1 or 2 days after treatment to those in untreated control rabbits. Dead immature flukes were recognized in the hepatic parenchyma 4, 7, and 14 days after treatment. During the early stage of infection they were surrounded by necrotic liver cells and eosinophils. The intensity of the reaction increased gradually and two distinct zones developed. The inner zone was composed of necrotic liver cells and eosinophils, and the outer zone was composed mainly of phagocytic mononuclear cells and fibroblasts.