Fresh produce contaminated during cultivation, harvesting, processing, and distribution has also been a source of hepatitis A. [12, 25] In 1997, frozen strawberries were the source of a hepatitis A outbreak in five states. [15] Six years later, in 2003, fresh green onions were identified as the source of a hepatitis A outbreak traced to consumption of food at a Pennsylvania restaurant. [25] Other produce, such as blueberries and lettuce, has been associated with hepatitis A outbreaks in the U.S. as well as other developed countries. [3, 4]

HAV is relatively stable and can survive for several hours on fingertips and hands and up to two months on dry surfaces. [11, 17] The virus can be inactivated by heating to 185°F (85°C) or higher for one minute, or disinfecting surfaces with a 1:100 dilution of sodium hypochlorite (household bleach) in tap water. [8, 13, 24]  It must be noted, however, that HAV can still be spread from cooked food if it is contaminated after cooking. [12]

Although ingestion of contaminated food is a common means of spread for hepatitis A, it may also be spread by household contact among families or roommates, sexual contact, or by direct inoculation from persons sharing illicit drugs. [12, 17] Children are often asymptomatic, or have unrecognized infections, and can pass the virus through ordinary play, unknown to their parents, who may later become infected from contact with their children. [11, 18, 22]

Symptoms of a Hepatitis A Infection

Hepatitis A may cause no symptoms at all when it is contracted, especially in children. [12] Asymptomatic individuals will only know they were infected (and have become immune, given that you can only get hepatitis A once) by getting a blood test later in life. [17] Approximately 10 to 12 days after exposure, HAV is present in blood and is excreted via the biliary system into the feces. [7, 11]  Although the virus is present in the blood, its concentration is much higher in feces. [11] HAV excretion begins to decline at the onset of clinical illness, and decreases significantly by 7 to 10 days after onset of symptoms. [11] Most infected persons no longer excrete virus in the feces by the third week of illness; children may excrete HAV longer than adults. [11, 20]

Seventy percent of hepatitis A infections in children younger than six years of age are asymptomatic; in older children and adults, infection tends to be symptomatic with more than 70% of those infected developing jaundice. [7] Symptoms typically begin about 28 days after contracting HAV, but can begin as early as 15 days or as late as 50 days after exposure. [7, 11, 12] The symptoms include muscle aches, headache, anorexia (loss of appetite), abdominal discomfort, fever, and malaise. [[7, 11, 17]

After a few days of typical symptoms, jaundice (also termed “icterus”) sets in. [11, 17] Jaundice is a yellowing of the skin, eyes and mucous membranes that occurs because bile flows poorly through the liver and backs up into the blood. [17] The urine will also turn dark with bile and the stool light or clay-colored from lack of bile. [7, 11, 17] When jaundice sets in, initial symptoms such as fever and headache begin to subside. [17]

In general, symptoms usually last less than 2 months, although 10% to 15% of symptomatic persons have prolonged or relapsing disease for up to 6 months. [13, 14] It is not unusual, however, for blood tests to remain abnormal for six months or more. [11] The jaundice so commonly associated with hepatitis A can also linger for a prolonged period in some infected persons—sometimes as long as eight months or more. [11, 17] Additionally, pruritus, or severe “itchiness” of the skin, can persist for several months after the onset of symptoms. These conditions are frequently accompanied by diarrhea, anorexia, and fatigue. [7, 17]

Relapse is possible with hepatitis A, typically within three months of the initial onset of symptoms. [14] Although relapse is more common in children, it does occur with some regularity in adults. [11, 14] The vast majority of persons who are infected with hepatitis A fully recover, and do not develop chronic hepatitis. [17] Persons do not carry hepatitis A long-term as with hepatitis B and C. [5, 7]

Fulminant Hepatitis A

Fulminant hepatitis A is a rare but devastating complication of HAV infection. [10] As many as 50% of individuals with acute liver failure may die or require emergency liver transplantation. [23] Elderly patients and patients with chronic liver disease are at higher risk for fulminant hepatitis A. [11, 23] In parallel with a declining incidence of acute HAV infection in the general population, however, the incidence of fulminant HAV appears to be decreasing. [23]

HAV infects the liver’s parenchymal cells (internal liver cells). [10, 11] Once a cell has been penetrated by the viral particles, the hepatitis A virus releases its own toxins that cause, in essence, a hostile takeover of the host’s cellular system. [11, 22] The cell then produces new viral components that are released into the bile capillaries or tubes that run between the liver’s parenchymal cells. [11] This process results in the death of liver cells, called hepatic necrosis. [11, 23]

The fulminant form of hepatitis occurs when this necrotic process kills so many liver cells—upwards of three-quarters of the liver’s total cell count—that the liver can no longer perform its job. [10, 23] Aside from the loss of liver function, fulminant hepatic failure can lead to encephalopathy and cerebral edema. [10] Encephalopathy is a brain disorder that causes central nervous system depression and abnormal neuromuscular function. [10, 11] Cerebral edema is a swelling of the brain that can result in dangerous intracranial pressure. [10] Intracranial hypertensions leading to brain stem death and sepsis with multiple organ failure are the leading causes of death in individuals with fulminant hepatic failure. [10, 23]

How is a Hepatitis A Infection Diagnosed

The various human hepatitis viruses cause very similar illnesses. [11] Therefore, neither the individual nor the healthcare provider can tell by symptoms or signs if a given individual is suffering from hepatitis A unless laboratory tests are performed. [7, 17]

Fortunately, blood tests are widely available to accurately diagnose hepatitis A, including tests for antibodies, or the affected person’s immune response to hepatitis A proteins. [7] This immune response is conclusively demonstrated by the presence of Immunoglobulin M (IgM) antibodies, indicating acute disease, and immunoglobulin G (IgG), indicating a past infection. [11, 13] The IgG antibodies are present for life, indicating immunity. [13] Following is some guidance for the interpretation of the test results:

• IgM negative / IgG negative: Most persons with these results have never contracted hepatitis A. Antibodies of the IgM variety develop five to ten days prior to the onset of symptoms.

• IgM positive / IgG negative: This result indicates acute hepatitis A.

• IgM positive / IgG positive: This result indicates that acute hepatitis A occurred within the last six months. By six months, the IgM reverts to negative.

• IgM negative / IgG positive: Persons with this result are immune to hepatitis A. They have either been infected with the virus months or years in the past (with or without symptoms), or they have been vaccinated for hepatitis A. However, if they are currently ill, it is not likely to be due to hepatitis A.

Treatment for Acute Hepatitis A Infections

Once a clinical infection is established, there is no specific treatment for hepatitis A.  Affected individuals generally suffer from loss of appetite, so the main concern is ensuring a patient receives adequate nutrition and avoids permanent liver damage. [7, 17] An individual’s perception of the severity of fatigue or malaise is the best determinant of the need for rest. [17]

Treatment of those suffering from fulminant hepatic failure depends largely on the affected person’s status.  [23, 26] Those who have not become encephalopathic generally undergo an intense course of supportive treatment.  [10, 23] But for those whose liver failure is so complete that it has lead to encephalopathy or cerebral edema, timely liver transplantation is often the only option. [10, 14] Unfortunately, many individuals with irreversible liver failure do not receive a transplant because of contraindications or the unavailability of donor livers. [11, 23]

Real Life Impacts

The number of acute hepatitis A infections in the U.S. drastically fell in the first part of the 21stCentury, largely in part because hepatitis A vaccination was recommended for persons in groups shown to be at high risk for infection and children living in communities with high rates of disease beginning in 1996.   By 2006, hepatitis A vaccine had been incorporated into the Advisory Committee on Immunization Practices’ recommended childhood vaccination schedule. [27]

Despite a decrease in the number of hepatitis A cases reported annually, anyone who has not been vaccinated is at increased risk for contracting hepatitis A infection.  Persons over the age of 50, those with chronic liver disease, and immunocompromised individuals who have not been vaccinated against hepatitis A remain most at risk for developing fulminant hepatitis, a rare but devastating complication of a hepatitis A infection that can lead to the need for a liver transplant, or death.

How to Prevent Hepatitis A

Hepatitis A is totally and completely preventable. [12] Although outbreaks continue to occur in the United States, no one should ever get infected if preventive measures are taken. [7, 12] For example, food handlers must always wash their hands with soap and water after using the bathroom, changing a diaper, and certainly before preparing food. [12, 24] Food handlers should always wear gloves when handling or preparing ready-to-eat foods, although gloves are not a substitute for good hand washing. Ill food-handlers should be excluded from work. [14, 24]

After exposure, immune globulin (IG) is 80% to 90% effective in preventing clinical hepatitis A when administered within 2 weeks of last exposure. [9] Although efficacy is greatest when IG is administered early in the incubation period, when administered later, IG is still likely to make the symptoms less severe. [9, 11] Given the lack of appropriately designed studies comparing the postexposure efficacy of vaccine with that of IG, the Advisory Committee on Immunization Practices (ACIP) recommends IG exclusively for post-exposure. [9] Hepatitis A vaccine, if recommended for other reasons, could be given at the same time. [9, 13]

In 2006, the ACIP recommended routine hepatitis A vaccination for all children ages 12-23 months, that hepatitis A vaccination be integrated into the routine childhood vaccination schedule, and that children not vaccinated by two years of age be vaccinated subsequently. [9, 13] The vaccine is recommended for the following persons:

• Travelers to areas with increased rates of hepatitis A
• Men who have sex with men
• Injecting and non-injecting drug users
• Persons with clotting factor disorders (e.g. hemophilia)
• Persons with chronic liver disease
• Persons with occupational risk of infection (e.g. those who work with hepatitis A-infected primates or with hepatitis A virus in a laboratory setting)
• Children living in regions of the U.S. with increased rates of hepatitis A
• Household members and other close personal contacts (such as regular babysitters) of adopted children newly arriving from countries with high or intermediate rates of hepatitis A. [9]

The vaccine may also help protect household contacts of those persons infected with hepatitis A. [9, 20] Although generally not a legal requirement at this time, vaccination of food handlers would be expected to substantially diminish the incidence of hepatitis A outbreaks. [12] Persons traveling to a high-risk area less than four weeks after receiving the initial dose of hepatitis A vaccine, or travelers who choose not to be vaccinated against hepatitis A should receive a single dose of Immune Globulin, which provides protection against hepatitis A infection for up to three months. [9, 11, 18]

For more information visit www.about-hepatitis.com.