Karst is a type of landscape where the dissolving of the bedrock has created sinkholes, sinking streams, caves, springs, and other characteristic features. Karst is associated with soluble rock types such as limestone, marble, and gypsum.
A: Scientists have identified 5 unique hepatitis viruses, identified by the letters A, B, C, D, and E. While all cause liver disease, they vary in important ways. Hepatitis A virus (HAV) is present in the faeces of infected persons and is most often transmitted through consumption of contaminated water or food.exual transmission is also possible, but is much less common. There is no vaccine for HCV. Hepatitis D virus (HDV) infections occur only in those who are infected with HBV. The dual infection of HDV and HBV can result in a more serious disease and worse outcome.
Hepatitis A virus is a picornavirus, a small single strand RNA virus; hepatitis B virus belongs to the hepadnavirus family of double stranded DNA viruses; hepatitis C virus is a flavivirus, a single stand RNA virus; hepatitis E, also an RNA virus, is similar to a calicivirus.uman hepatitis B virus (figure 3) is the prototype virus of the hepadnavirus family and causes serum hepatitis. HBV has a diameter of about 40nm. It infects humans and chimpanzees but there are closely related members of this family that infect other mammals and birds. HBV is a DNA virus and is enveloped.