{"id":20811,"date":"2024-09-10T14:28:34","date_gmt":"2024-09-10T04:28:34","guid":{"rendered":"https:\/\/mvec.mcri.edu.au\/?post_type=references&p=20811"},"modified":"2024-11-14T11:30:00","modified_gmt":"2024-11-14T00:30:00","slug":"hepatitis-a","status":"publish","type":"references","link":"https:\/\/mvec.mcri.edu.au\/vi\/references\/hepatitis-a\/","title":{"rendered":"vi\u00eam gan A"},"content":{"rendered":"
<\/p>\n
\n

What is it?<\/h2>\n

Hepatitis A is an infection caused by the hepatitis A virus (HAV). HAV belongs to the family <\/span>Picornaviridae<\/span><\/i>, genus <\/span>Hepatovirus<\/span><\/i>. It replicates primarily in liver cells and is one of the most common causes of acute hepatitis (inflammation of the liver) worldwide.<\/span><\/p>\n

Unlike infection with hepatitis B and C viruses, HAV infection does not usually cause chronic liver disease.<\/span><\/p>\n<\/div>\n

\n

What to look for<\/h2>\n

The incubation period for hepatitis A infection is 15 to 50 days. Infected children generally experience either no symptoms or mild symptoms only. Approximately 70% of infected adults will be symptomatic. Symptoms of infection fit into two distinct phases, a prodromal (pre-icteric) phase and an ictreric (jaundice) phase. Prodromal phase features include <\/span>general malaise and exhaustion,\u00a0fever,\u00a0<\/span>nausea and lack of appetite and <\/span>abdominal pain. Icteric phase features include <\/span>pruritus (itchy skin), dark urine, pale stools and yellowing of the eyes and skin.<\/p>\n

The duration of symptoms can vary, lasting only a few weeks or as long as 6 months. Liver function tests can take 1 to 2 months to normalise after the onset of infection. In rare cases, infection can result in fulminant hepatitis (acute liver failure), which may be fatal without liver transplant.<\/span><\/p>\n

Hepatitis A mortality rates increase with age and can be associated with the presence of underlying medical risk factors. Up to 10% of cases will relapse; all relapsed cases will recover.<\/span><\/p>\n

Rarely, hepatitis A can also lead to pancreatitis, rash, nephritis (kidney inflammation) or glomerulonephritis (inflammation of the glomeruli, small blood vessels in the kidney), pneumonitis (lung tissue inflammation), pericarditis (inflammation of the lining of the heart muscle), haemolysis (the destruction of red blood cells), and acute cholecystitis (gallbladder inflammation). Guillain\u2013Barr\u00e9 syndrome<\/a>, encephalitis (brain inflammation) and central myelitis (spinal cord inflammation) have also been reported.<\/span><\/p>\n

How is it transmitted?<\/h2>\n

Hepatitis A is highly infectious. Cases are considered infectious from two weeks prior to the onset of prodromal phase up until either one week after the onset of jaundice (if present) or two weeks after the onset of the prodromal phase (if there is no jaundice). People with asymptomatic infections can still transmit disease.<\/span><\/p>\n

Transmission occurs through the faecal\u2013oral route,<\/span> close person-to-person contact, contaminated food and water, and via fomites (e.g. fabric and other surfaces contaminated by faeces). Common sources include:<\/span><\/p>\n