Hepatitis A is a form of viral hepatitis, caused by the hepatitis A virus, a single-stranded, positive-sense, linear RNA enterovirus of the Picornaviridae family. The virus spreads by the fecal-oral route and infections often occur in conditions of poor sanitation. The incubation period usually lasts 2 to 6 weeks. Symptoms may include fatigue, fever, nausea, myalgia, jaundice and pruritus. Recurrence and chronic hepatitis do not usually occur.
The clinical symptoms vary from person to person, with some patients remaining asymptomatic or suffering from less severe symptoms. The subclinical cases are more common in children less than 5 years of age. The manifestation of HAV starts with a prodrome stage of fever with chills, anorexia, malaise, fatigue and abdominal pain. These symptoms last for a week. These are followed by diarrhea, nausea, vomiting, headache, and arthralgia.
Thereafter jaundice appears, with yellowing of skin and sclera, dark colored urine and pale stools. There is intense pruritis with skin rash. Signs include hepatomegaly, lymphadenopathy and splenomegaly, though these findings vary from individual to individual, depending on general health status and age group.
The individual remains infective from 15-20 days before the appearance of jaundice to 8 days after jaundice disappears. After the jaundice resolves, the other symptoms begins to diminish. The hepatomegaly continues for another 2-12 weeks and thereafter the liver regains its normal function .
Hepatitis A is best diagnosed serologically. Various types of serologic tests are available, like electron microscopy [EM], complement fixation, immune adherence haemagglutination, radioimmunoassay and enzyme immunoassay. Of these, immune adherence haemagglutination is the one most frequently used. In serologic tests, serum IgM for HAV is detected. This appears within the first week of infection and is positive till 6 months of the illness. Thus, it represents the active or current infection in an individual. This is followed by the detection of IgG antibodies. These antibodies persist lifelong and represent an old infection.
Blood tests include a complete liver function test. It shows an abnormal elevation of ALT, AST, serum bilirubin and alkaline phosphatase which represents acute hepatitis A. Elevated ALT is the sole indicator of liver damage.
As HAV infection is a self limiting illness; there is no specific treatment. Supportive care is done by adequate fluid rehydration and nutritional support. Continuous monitoring is done and rest is recommended .
Antiemetics are administered for nausea and vomiting. Intravenous fluid therapy is initiated to prevent dehydration. Family members of the infected person are vaccinated to prevent the risk of gaining infection. Patients are advised to stop fatty, oily food and alcohol.
There is no chronic infection or recurrent infection of hepatitis A. Once infected, the individual gets life time immunity. The prognosis is good. Rarely does the infection prove fatal. This is determined through the age of the individual; elderly have a high risk of bad prognosis and the underlying liver disease, that may lead to acute fulminant hepatitis.
On an average, 100 people die every year in the United States with acute liver failure due to hepatitis A infection. It was also found that most deaths occurred in people older than 50 years, thus age is the prime factor in determining the severity of the illness .
It is caused by hepatitis A virus [HAV]. HAV is a single stranded RNA virus belonging to the picornavirus family. This virus is non-enveloped and though there are multiple genotypes, only one serotype exists. This virus was first isolated in the year 1979. The virus is capable of surviving in low pH levels and in moderate temperatures. Also, it can be stable for months together in environment. HAV is transmitted through faeco-oral route, person to person contact and is rampant in places with overcrowding and poor hygienic conditions. Common sources for outbreaks are contaminated food and water with HAV virus. This is seen with people handling food or processing food that is infected with the virus  .
There are millions of people getting infected by this virus throughout the year. In the year 1988, about 27,000 cases were recorded in the United States and in the year 1995, about 32,000 cases were noted. From 1995-2006, there was a reduction in the hepatitis A infection, as large number of children were vaccinated for HAV. Thus, only 1.2 cases per 100,000 populations were recorded.
Children in the age group 5-14 years are more likely to be infected . Over 40 years record reveals that average age of infection increases gradually. Its geographical distribution differs with the socio economic conditions, thus developing countries with poor hygienic conditions are largely infected by this virus. Individuals at risk include male homosexuals, childcare workers, foreign travelers and those with low socio-economic conditions .
After reaching the liver, the virus enters the liver cells. The ribosome in the host binds together and forms polysomes. They synthesize the viral proteins. These then assemble together and are shed in the biliary tree and excreted in the faeces.
An inflammatory process begins throughout the liver. The hepatocytes are invaded by the virus and are destroyed. During the incubation period, large numbers of virus are detected in the faeces of the infected person. Other changes occurring in the liver comprise of focal activation of sinusoidal lining cells; accumulation of histiocytes and lymphocytes in the parenchyma of the liver. These replace the destroyed hepatocytes of the liver that have undergone necrosis. These changes mainly occur in the periportal areas. Occasionally, focal degeneration along with coagulative necrosis in the form of acidophilic bodies is seen .
During the incubation period, host defenses develop antibody against the hepatitis virus. Specific HAV IgM antibody is found in the serum within a week of infection. Its maximum levels are reached after the first week and the levels slowly decline during 40-60 days of the infection. After this, IgG specific antibody appears, and persists for many years. This antibody is protective and is a marker for a past infection in the host .
Hepatitis A infection can be transmitted from person to person; hence, individuals must take precautions in order to check its spread. They must wash hands thoroughly using a disinfectant, especially before food preparation, before and after eating food, before and after using toilets and after changing nappies of children. Strict sanitation and proper waste disposal especially of faeces should be done. Travelers should use boiled or cooked food. They should avoid dairy products and raw vegetables. Vaccination is advised before travelling to countries where the outbreaks are known to occur. Preferably use bottled water and if unavailable, then boil water before consuming.
Passive prevention of hepatitis A is done by administration of pooled normal human immunoglobulin. This should contain more than 100IU/ml anti HAV. It is administered intramuscularly at a dose of 2 IU/kg body weight. Hepatitis A vaccines are safe and provide fare immunity against the infection. The centre for disease control and prevention [CDC] has regulated a vaccine programme for children and adults. After the first dose, a booster is administered after 6- 12 months. These vaccines are especially advised to the individuals having an occupational risk, such as, laboratory workers; these are at a risk of acquiring infections during their course of work in microbiological laboratories. Other high risk persons include sewage workers as they are continuously exposed to raw sewage, food handlers and healthcare workers .
The word hepatitis refers to an inflammation of the liver. Hepatitis A is one of the commonest and oldest diseases known till date. It’s a viral infection which results in inflammation of liver caused by hepatitis A virus. Hepatitis A is a self limiting disease lasting from 2 weeks to several months which might culminate into severe disability. Once infected, HAV produces life time immunity and there is a no carrier state. Hepatitis A can prove fatal to an individual who already has an underlying chronic liver disease .
Hepatitis A infection is a common liver infection that causes liver inflammation resulting in jaundice. This disease is transmitted through transmission of the Hepatitis A virus from infected faeces to food. This is frequently seen in countries with poor sanitation facilities.
This infection can be prevented by observing proper hygiene, like, washing hands before eating food and before cooking or handling food. Also to wash hands after using toilets. Vaccination can also provide immunity to individuals at risk.