Hepatitis A
About one third of the US population has antibodies to hepatitis A, indicating previous infection by the virus. The hepatitis A virus infects up to 200,000 Americans every year and causes symptoms in about 134,000 of them. Almost 30% are children under age 15.
Hepatitis A (formerly called infectious hepatitis) is excreted in feces and transmitted by contaminated food and water. Eating shellfish taken from sewage-contaminated water is a common means of contracting hepatitis A. Infected people can transmit it to others if they do not take strict sanitary precautions. Hepatitis A is infectious for two to four weeks before symptoms develop and for a few days afterward.
Among the people at risk for passing the infection along or being infected are the following:
- International travelers. Hepatitis A is the hepatitis strain people are most likely to encounter in the course of international travel. In fact, in spite of the availability of a vaccine, the increase in travel to underdeveloped countries has kept the incidence of hepatitis A steady in Western nations. The incidence may even be increasing.
- Day care employees and children. It is estimated that between 11% and 16% of hepatitis A cases occur among day care employees and children who attend day care. The risk for children attending day care is very low, however, if hygienic precautions are used, particularly when changing babies and handling diapers.
- Sexually active homosexual men.
- Intravenous drug users.
- Health care, food industry, and sewage workers.
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| A fly may act as a mechanical vector of diseases such as Hepatitis A, which means the fly carries the infective organism on its feet or mouth parts and contaminates food or water which a person then consumes. A biological vector actually develops an infective organism in its body and passes it along to its host, usually through its saliva. A fly can be a biological vector, as in the transmission of leishmaniasis by the sandfly. |
Symptoms of Acute Hepatitis
Symptoms of acute viral hepatitis may begin suddenly or develop gradually. They may be so mild that patients mistake the disease for the flu. They include the following:
- Nearly all patients experience some fatigue and often have mild fever.
- Gastrointestinal problems are very common, including nausea, vomiting, a general feeling of discomfort in the abdomen, or a sharper pain that may occur in the upper right area if the abdomen. This pain tends to increase during jerking movements, such as climbing stairs or riding on a bumpy road.
- GI problems can lead to loss of appetite, weight loss, and dehydration.
- After about two weeks, dark urine and jaundice (a yellowish color in the skin and whites of the eyes) develops in some, but not all, patients. (Children tend not to develop jaundice.)
- About half of all hepatitis patients have light colored stools, muscle pain, drowsiness, irritability, and itching, usually mild.
- Diarrhea and joint aches occur in about a quarter of patients.
- The liver may be tender and enlarged and most people have mild anemia.
- In about 10% of patients, the spleen is enlarged.
Preventing Hepatitis A Infections When Traveling to High-Risk Countries
Travelers should take the following precautions:
- Be vaccinated against hepatitis A and possibly B if traveling for long periods of time to countries where epidemics occur.
- Use only carbonated bottled water for brushing teeth and drinking. (It should be noted that ice cubes can carry infection.) Boiling water is the best method for eliminating infectious agents. There is some debate about how long to boil, but bringing the water to a good boil for at least a minute generally renders it safe to drink.
- Heated food should be hot to the touch and eaten promptly.
- Dont buy food from street vendors.
- Beware of sliced fruit that may have been washed in contaminated water. Travelers themselves should peel all fresh fruits and vegetables.
- Avoid dairy products.
- Avoid raw or undercooked meat and fish.
Vaccinations for Hepatitis A
Two vaccines (Havrix, Vaqta) are now available and both are very safe and effective for preventing hepatitis A (HAV). They can be given along with immune globulin and other vaccines. A 2001 study also strongly suggested they may be used interchangeably (i.e., if one is given as the first vaccination, the other may be safely used as the booster). A combination vaccine (Twinrix) that contains both Havrix and Engerix-B (a hepatitis B vaccine) is now approved for people with risk factors for both hepatitis A and B.
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Click the icon to see a discussion of hepatitis A vaccine. |
Candidates for HAV Vaccinations. Vaccinations for hepatitis A are recommended for the following individuals:
- People in specific populations where outbreaks occur. Indeed, a 2001 study showed that widespread vaccination of children in one county in California led to dramatic decreases in the number of outbreaks among all adults in the community at large. Day care centers are highly associated with such outbreaks, although risks in such centers vary widely depending on the community, so universal immunization in day care centers is not recommended.
- Sexually active homosexual men.
- Patients with any form of chronic hepatitis. (It should be noted that the HAV vaccination should be given to patients before they reach advanced stages of liver disease, when there is a lower rate of response.)
- Health care workers exposed to the virus.
- Travelers to developing countries. (Travelers should also receive immune globulin if they are visiting high-risk areas within four weeks of the vaccination.)
- Experts now recommend routine vaccinations for children and adolescents in high-risk states. These states are Arizona, Alaska, California, Idaho, Nevada, New Mexico, Oklahoma, Oregon, South Dakota, Utah, Washington, Missouri, Texas, Colorado, Arkansas, Montana, and Wyoming.
- People who have had intimate exposure to patients with hepatitis A may be protected with immune globulin or possibly with the vaccine itself.
- People with chronic liver disease, including those with hepatitis C, should also be vaccinated, particularly if they have not been exposed to hepatitis A, since the infection can cause liver failure in these patients.
Side Effects. Although there are few side effects, allergic responses from the vaccination can occur. Hair loss has been reported in a very few people after a second administration. There may be pain at the injection site. (Havrix causes more pain at the injection site than Vaqta.)
Symptoms of Hepatitis A
Symptoms are usually mild, especially in children and generally appear between two and six weeks after exposure to the virus. Adult patients more likely to have fever, jaundice, and itching that can last one to several months.
General Outlook for People Infected with Hepatitis A
This is the least serious of the common hepatitis viruses. It does not directly kill liver cells and there is no risk for a chronic form. Fulminant hepatitis is the only major concern, but even if it develops, it is almost always less dangerous than with other viral types. Only one in a thousand patients are at risk for death from this complication. If hepatitis A infection occurs in patients with hepatitis C, however, superinfections can occur, even without cirrhosis, leading to a life-threatening form of fulminant hepatitis. (Infection of patients with hepatitis B who do not have cirrhosis does not appear to be as dangerous.)
Specific Tests for Hepatitis A
Radioimmunoassays are generally used to identify IgM antibodies, first produced to fight hepatitis A. They appear early in the course of the disease and usually can be identified as soon as symptoms appear. IgM antibodies disappear during recovery, but those known as IgG antibodies persist, and their presence can be used to indicate a previous infection.
Treatments and Measures to Prevent Transmission of Hepatitis A
The primary goals for managing acute viral hepatitis are to provide adequate nutrition, to prevent additional damage to the liver, and to prevent transmission to others.
Precautions for Preventing Transmission of Hepatitis A. Because hepatitis A (and also hepatitis E) are usually passed through contaminated food, people with these viruses should not prepare food for others; unfortunately, these viruses are most contagious before symptoms appear.
- Using hot water when cleaning utensils or clothing is essential. Heating a contaminated article for a minute kills the virus. Simple household bleach is effective for disinfecting hard surfaces. Sterilizing is not necessary. Still, even with strong precautions, utensils used by the patient for eating and cooking should be kept separate from those used by others.
- Abstain from sexual activity or take strict precautions.
- Abstain from alcohol. Moderate drinking (one or two drinks per evening) after recovery is not harmful for most people.
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