The onset of viral hepatitis is fast or sudden, and it depends on the type of hepatitis. Viral hepatitis can be categorized into acute hepatitis, chronic hepatitis, liver failure, cholestatic hepatitis, and cirrhotic hepatitis. Acute hepatitis and liver failure typically have a rapid onset, with common pathogens like Hepatitis A and Hepatitis E, which can cause acute hepatitis and may lead to symptoms such as significant fatigue, poor appetite, and dark urine in a short period. However, chronic hepatitis caused by Hepatitis B and Hepatitis C, which can even lead to cirrhosis, tends to progress slowly. After infection with the virus, the body may carry the virus for a long time without any symptoms. It may take 10-20 years or even longer for symptoms like fatigue and poor appetite to appear.