Hepatitis D is caused by a defective RNA virus (delta agent) that can replicate only in the presence of hepatitis B virus. Hepatitis B infection rarely occurs as coinfection during acute hepatitis B or as superinfection during chronic hepatitis, also type B.
Peptic ulcer: what is it?
Peptic ulcer is a disease of considerable social importance. Current data show that in Western countries, 2% of the population has an active ulcer, while 6-15% have presented clinical manifestations