Viral hepatitis is primarily due to infection by certain hepatitis viruses. Different types of viral hepatitis have different modes of transmission and routes of spread, and their outcomes and prognoses also vary. Hepatitis A and E are mainly transmitted through the digestive tract and the fecal-oral route, typically from consuming food or water contaminated with hepatitis A or E viruses. Hepatitis B and C, on the other hand, are mainly transmitted through blood, perinatal transmission, and sexual contact, with infection from casual contact being rare.