AGENCY FOR TOXIC SUBSTANCES AND DISEASE REGISTRY

Viral hepatitis

Viral hepatitis is liver inflammation due to a viral infection. It may present in acute form as a recent infection with relatively rapid onset, or in chronic form.

Hepatitis A or infectious jaundice is caused by hepatitis A virus (HAV), a picornavirus transmitted by the fecal-oral route often associated with ingestion of contaminated food. It causes an acute form of hepatitis and does not have a chronic stage. The patient's immune system makes antibodies against HAV that confer immunity against future infection. People with hepatitis A are advised to rest, stay hydrated and avoid alcohol. A vaccine is available that will prevent HAV infection for up to 10 years. Hepatitis A can be spread through personal contact, consumption of raw sea food, or drinking contaminated water. This occurs primarily in third world countries. Strict personal hygiene and the avoidance of raw and unpeeled foods can help prevent an infection. Infected people excrete HAV with their feces two weeks before and one week after the appearance of jaundice. The time between the infection and the start of the illness averages 28 days (ranging from 15 to 50 days), and most recover fully within 2 months, although approximately 15% of sufferers may experience continuous or relapsing symptoms from six months to a year following initial diagnosis.

Patients with chronic hepatitis B have antibodies against the virus, but not enough to clear the infected liver cells. The continued production of virus and countervailing antibodies is a likely cause of the immune complex disease seen in these patients. A vaccine is available to prevent infection for life. Hepatitis B infections result in 500,000 to 1,200,000 deaths per year worldwide due to the complications of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Hepatitis B is endemic in a number of (mainly South-East Asian) countries, making cirrhosis and hepatocellular carcinoma big killers. There are eight treatment options approved by the U.S. Food and Drug Administration (FDA) available for persons with a chronic hepatitis B infection: alpha-interferon, pegylated interferon, adefovir, entecavir, telbivudine, lamivudine, tenofovir disoproxil and tenofovir alafenamide with a 65% rate of sustained response.

The Hepatitis D virus (HDV) or hepatitis delta agent belongs to the genus Deltavirus and causes Type D Hepatitis. It is similar to a viroid as it can only propagate in the presence of the hepatitis B virus, depending on the helper function of HBV for its replication and expression. It has no independent life cycle, but can survive and replicate as long as HBV infection persists in the host body. It can only cause infection when encapsulated by hepatitis B virus surface antigens.

The Hepatitis E virus (HEV), from the family Hepeviridae, produces symptoms similar to hepatitis A, although it can take a fulminant course in some patients, particularly pregnant women (mortality rate about 20%); chronic infections may occur in immune-compromised patients. It is more prevalent in the Indian subcontinent. The virus is feco-orally transmitted and usually is self-limited.

The GB virus C is another potential viral cause of hepatitis that is probably spread by blood and sexual contact. It was initially identified as Hepatitis G virus. There is very little evidence that this virus causes hepatitis, as it does not appear to replicate primarily in the liver. It is now classified as GB virus C.

 


https://www.creativsymantec.com - new movies site.