Text Copyright 2007 by Nancy Sculerati MD - all rights reserved

• Hepatitis A
• HAV

Hepatitis A is the most common kind of viral hepatitis. It infects people all over the world, especially in developing countries without sophisticated sewerage plants.

Both the hepatitis (liver inflammation), and the virus that causes it, are properly called "Hepatitis A". This disease is almost always self-limited disease, in other words: it gets better by itself.

The most usual symptoms of hepatitis A are general fatigue and low grade fever, followed by the yellowing of the skin and eyes called jaundice. Often, especially in children, Hepatitis A infection causes such mild inflammation of the liver that there are no, or very few, of the clinical symptoms of illness. However, jaundice may occur even in some children - and is usual in older adults. When the illness is symptomatic, it usually causes malaise, fatigue, right upper belly pain and tenderness, and jaundice. It lasts about 3 weeks. Rarely, Hepatitis A may have a fulminant and fatal course.

Hepatitis A never becomes a chronic infection. That makes it less worrisome than the next two most common causes of viral hepatits, hepatitis B and hepatitis C.

The yellow cast of the whites of eyes and skin color is due to jaundice from hepatitis A infection. These are signs of active liver inflammation that occurs while the virus is multiplying in liver cells.

Although the hepatitis A virus is highly contagious from person to person, passed by contact with tiny amounts of stool that are left on the skin. It doesn't take a "dirty" person to have such traces on their skin, it only takes a person who did not thoroughly wash hands with soap and water after going to the bathroom. HVA is also commonly acquired by eating contaminated foods. Those foods are frequently fresh fruits or vegetables harvested by a person with hepatitis A, or cooked meals prepared or served by a person with hepatitis A. These are the usual ways that it is transmitted - person to person contact, & eating contaminated foods.

• Additionally, like hepatitis B and C, "Hep" A can be spread through blood transfusions, intravenous drug use, and sex. Unlike hepatitis B and C, those routes are all uncommon or rare ways to catch the disease, instead the usual route of transmission is fecal - oral. It's not as if a person has to knowingly eat shit to catch a disease by this route- all that has to happen is a microscopic amount of poop is left on hands and gets spread to face and mouth, or to food. The hands that carry those microscopic amounts of excrement are often those of children.

Hepatitis A is especially common in areas with raw sewerage or marginal sewerage facilities. The severity of the disease, on average, is very much age-related, very mild if striking infants and toddlers, very severe if contracted by older adults and the elderly. Hepatitis A is so common in some areas of the world, like India, that almost everyone gets it young and, by the time adulthood comes, the entire population has immunity. That's one reason why adult travelers from parts of the world where the disease is not widespread should consider vaccination against hepatitis A, or use precautions when visiting areas where the disease is a usual childhood illness. Although rarely they rarely die from the disease, older children and adults often become quite sick for several weeks after contracting Hepatitis A.

Hepatitis A is easily spread to adults and older children by infected babies in day care settings, and in large families. When infants and young toddlers have hepatitis A, diapering becomes a high risk activity for their caretakers. In countries like the United States, where the disease exists at a low rate overall, there are pockets of the population where Hepatitis A is much more common - often where there are large numbers of young children.

Hepatitis A Facts:

• Of all cases of acute hepatitis (acute inflammation of the liver) in the United States, it's estimated that just under half (about 46%) are due to Hepatitis A.
• The liver inflammation caused by this virus can range from very minor to very severe. When very minor, the infected person may be entirely asymptomatic (without symptoms) . If it is severe enough to interfere with overall liver function, then jaundice will develop. In rare cases, Hepatitis A infection is extremely severe (fulminant) and fatal.
• There are no reported cases of chronic infection with Hepatitis A.
• Young children usually have very mild infections, it's unusual for a child under 4 with hepatitis A to develop jaundice. Instead, infections in that age group are either entirely asymptomatic, or nearly so. Young adults with Hepatitis A develop jaundice about half the time, whereas senior citizens are quite likely to become jaundiced. Generally, the severity of the disease is age-related.

• Typically, the Hepatitis A virus is eaten on contaminated food, or is swallowed because a tiny amount of infected stool inadvertently lodged on one's finger, and that finger was placed in the mouth.
  • This route of infection explains why frequent hand-washing, thorough cooking of foods, as well as avoiding eating the peel of raw fruits and vegetables all help reduce the chances of catching Hepatitis A in endemic areas.
• The virus particles pass through the stomach without being digested and are absorbed in the GI tract, where they enter the portal circulation to the liver.
• It is only in the liver cells that they multiply. Hepatitis A virions shed their capsid coats outside the cells and enter these liver cells through receptor sites on the surface of the hepatocyte (liver cell). Inside the cell, the virus RNA calls up the in the , and begins RNA synthesis. The incubation period of Hepatitis A is somewhere between 15 and 50 days- because that's how long it takes for the virus to get into to the liver and replicate, lysing liver cells .
• New virus particles pass ino the bile ducts and so end up in the bile.
• The bile, as usual, flows into the small intestine and mixes with digested food. The virus passes through the gut with its contents, and so virus is shed into the outside world the stool, as the contents of the intestine are excreted.
• In this manner, the infected person's stool carries live virus. Virus particles are found in the stool for about a week before signs of illness and for about 2 weeks afterwards. That's the period that the virus is replicating in the liver cells.

This map divides the world into areas with high, intermediate, and low rates of Hepatitis A. In the areas of high rates, Hepatitis A is a usual childhood disease and there are very high rates of immunity among adults.

Lab Test Results in Hepatitis A Infection

• Chapter 111 - Acute Viral Hepatitis in Mandell, Bennett, & Dolin: Principles and Practice of Infectious Diseases
• BETH P. BELL DAVID A. ANDERSON STEPHEN M. FEINSTONE: Chapter 170 – Hepatitis A Virus in Mandell, Bennett, & Dolin: Principles and Practice of Infectious Diseases

• http://www.nlm.nih.gov/medlineplus/hepatitisa.html

http://www.ncbi.nlm.nih.gov/ICTVdb/index.htm

• http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/index.htm