The etiology of extrahepatic biliary atresia (EHBA) in newborns remains unknown, although a first infectious animal model with complete obstruction of the common bile duct could be established. Intraperitoneal inoculation of newborn Balb/c mice with rhesus rotavirus induced cholestasis, leading, in most cases, to biliary atresia with lethal outcome, similar to EHBA in human newborns. The influence of interferon-α (IFN-α) on the hepatotropism of rotavirus infection was investigated in this animal model. Single-dose therapy with 10 000 IU of IFN-α protected all rhesus rotavirus-infected pups from cholestatic disease. The same dose, injected 5 d after infection, had no protective effect. Starting with onset of cholestatic symptoms, the treatment with 10 000 IU of IFN-α daily showed good results in 29 mice. Seventy-six percent of the mice recovered after 1 wk of therapy. Histologic investigation revealed normal findings in the hepatobiliary tract of clinically normal mice. Twenty-one percent of the descendants of infected and prophylactic IFN-α-treated mice showed cholestatic symptoms after infection with rhesus rotavirus (79% in an untreated control group) and a milder form of the illness. In conclusion, we found that prophylactic treatment with IFN-α prevented the hepatobiliary system of newborn Balb/c mice from severe damage by rhesus rotavirus in this artificially designed infectious model for EHBA. Infected and icteric mice, treated for 1 wk with IFN-α, had good prospects for recovery and prevention of complete and irreversible occlusion of the extrahepatic bile ducts. Infected and prophylactic IFN-α-treated dams gave good protection to their descendants. This means that EHBA in this model could probably be averted by maternal antibodies against rotavirus.