Hepatitis C is a disease of the liver caused by a virus that was first discovered in 1989. Prior to the discovery of the virus, it was known that some agent caused hepatitis or inflammation of the liver in people who had been given blood, and it was known that the agent could be transmitted to patients and to experimental animals in blood. In most cases, the disease is asymptomatic for years, even decades, before progressing to chronic liver disease. It is estimated that around 4.5 million people in the United States are infected with hepatitis C, and over 200 million around the world. Liver failure due to hepatitis C is the leading cause of liver transplants in the United States.
Fungi are parasitic in nature.
They grow in a living host or on a dead animal. Fungi that grow in ventilation systems may contaminate indoor environments and cause a variety of problems. Some fungi can cause lung infections. Many fungi can cause allergic reactions in susceptible people and respiratory irritation in non-allergic people. Inhalation of fungal spores by highly susceptible people can have fatal consequences.