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. The hepatitis A virus (HAV) causes a liver disease in humans now known as hepatitis A (historically known as infectious jaundice, viral hepatitis and infectious hepatitis). There are a number of different hepatitis viruses but only HAV, and possibly the hepatitis E virus, can cause foodborne disease.Hepatitis A is usually spread when HAV is ingested following contact with objects, food or drinks contaminated by the faeces of an infected person.As an enteric virus, hepatitis A shares some characteristics with norovirus.orovirus is the name given to a group of related viruses that were first described following an outbreak of gastroenteritis in a school in Norwalk, Ohio in 1968. They are highly infectious enteric viruses â fewer than 100 virus particles can cause infection (1) â and are the major cause of gastroenteritis in humans.