Effect of extract from N. sativa on morphological changes of Vero cell lines caused by Peste des Petit ruminants virus (PPRV). Microscopic view of the inhibition of N. sativa extracts on cytopathic effect (CPE) formation at about 96 h postinfection by PPRV. A, CPE of Vero cells infected by PPRV; B, Vero cells infected by PPRV and N. sativa extract (100µg/ml); C, Vero cells infected by PPRV and N. sativa extract (50µg/ml).