Hepatitis A Virus (HAV)

Virus name: genus: Heparna-virus (Hep-A-RNA-virus), Hepatitis A Virus (HAV)

Size and Shape: 28nm icosahedral particle with cubic symmetry

Structure: non-enveloped

Genome: single-stranded RNA (7.48kb), linear and positive-sense

Human disease: Hepatitis A

Infection with hepatitis A virus (HAV) causes acute, contagious liver disease. “Hepatitis” means “inflammation of the liver” and affects the ability of the liver to function properly.

(You may have heard of hepatitis A, B, and C, which are all different diseases caused by three different viruses. Some symptoms are similar, however there are different modes of transmission for these viruses and they can affect the liver in different ways. Hepatitis A tends to appear as an acute disease rather than a chronic condition.)

Transmission:

HAV is found in the fecal matter of infected individuals and can be passed to non-infected people via the ingestion of fecal matter, even in microscopic amounts (fecal-oral route). This often happens from close personal contact or through fecal-contaminated objects/food. In fact, it is one of the most frequent causes of foodborne infection.³

Because of this, it is always important to wash your hands after you use the bathroom or change a diaper. Improper hand washing can pass the virus to other individuals or to objects/foods, which can spread the virus.

People traveling to countries where hepatitis A is more common—areas with poor sanitation/personal hygiene—may need to be more careful. Fruits, vegetables, shellfish, ice, and water are most likely to be contaminated.

Sewage-contaminated or inadequately-treated water can lead to waterborne outbreaks of hepatitis A. We don’t need to worry about this as much in the US, because chlorination in the water supply kills HAV.

HAV can live outside the body on surfaces for months. Freezing does not kill the virus, however, heating contaminated foods/liquids for at least one minute at 185°F (85°C) will kill the virus.

Incubation period:

The incubation period for HAV tends to be 14-28 days, and symptoms tend to appear somewhere from 2-6 weeks after exposure.

Symptom-less people can spread the virus, and those who develop symptoms are contagious for two weeks before the symptoms appear.

Symptoms:

Infection with HAV can last from a few weeks, in those who have mild illness, and up to several months in those who have severe illness.

Some people, however, do not get symptoms. Children are less likely to show symptoms than adults. And infected children under six years do not usually experience symptoms, with only 10% experiencing jaundice.³ About 70% of older children and adults will experience jaundice.³

The symptoms of the virus may include any or all of the following, and may begin to appear over several days:

• Flu-like illness: low-grade fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain
• Clay-colored bowel movements
• Joint pain
• Jaundice (a yellowing of the skin/whites of eyes), dark urine
• Severe stomach pains and diarrhea (in children)

Not everyone who is infected will have all of these symptoms. The symptoms tend to last under two months, however they may hang around for up to 6 months. Adults who get hepatitis A are often too ill to work for up to a month.

Some people may experience symptoms for longer than usual, or the symptoms may go away and then reappear after several weeks. The infection that causes this phenomenon is no more severe than the infection that causes the normal course of the virus.

In rare cases, HAV can cause acute liver failure—a loss of liver function that occurs suddenly. People who are at the highest risk for liver failure are normally older adults who contract HAV and who already have chronic liver diseases. This requires hospitalization and sometimes a liver transplant.

Who is at higher risk?

• People traveling to countries where hepatitis A is more common—places with poor sanitation and lack of safe drinking and bathing water—and not being vaccinated
• Homosexual men
• Illegal drug users
• People with clotting-factor disorders, such as hemophilia
• People with chronic liver diseases such as hepatitis B or C
• People who are HIV positive
• People living with or taking care of someone with hepatitis A
• Those who have oral-anal sexual contact with someone who has hepatitis A
• People working closely with HAV in a research laboratory

Diagnosis:

Because hepatitis A cases are often not distinguishable from other types of acute viral hepatitis, a specific blood test can determine if a patient has HAV.

The blood test will look for HAV-specific antibodies (IgM and IgG) in the blood.

More specialized testing can detect the viral RNA through a process called reverse transcriptase polymerase chain reaction (RT-PCR), however this requires a more specialized laboratory to perform the test in.

Treatment:

If you have been exposed to HAV but haven’t been vaccinated, then you may want to contact your doctor to discuss your health options. One such option may include a quick injection of either the Hep A vaccine or the Hep A immunoglobulin. Both of these must be given within the first two weeks after exposure.

If you have symptoms that are worrying to you, you may also want to contact your doctor.

There is no specific treatment for hepatitis A.

Patients with hepatitis A will have less energy and tend to get tired more easily for several months. Plan on resting when you can.

Learn to cope with nausea by eating many small meals rather than several large meals. And choose high calorie and nutrient-rich foods to maintain energy and better overall health.

Rest your liver. If you are taking any medications, you would be wise to consult a doctor. Some medications may further damage the liver, and should be avoided. Alcohol should also be avoided.

Occasionally people who are infected need to be treated in the hospital (1 in five people)². Even in the hospital, treatment still remains rest, proper nutrition, and proper fluid intake to replace what is lost from vomiting and diarrhea.

Prognosis:

Thankfully, hepatitis A a does not become a chronic infection, meaning symptoms will clear up after a few months. And almost all people who become infected with HAV recover fully.

On rare occasions, the virus can cause acute liver failure (fulminant hepatitis) and death. This is more commonly seen in patients over 50 years old and those with chronic liver disease.

There are about 3-6 deaths/1,000 cases.²

Prevention:

There is a vaccine for HAV, called the hepatitis A vaccine (Hep A). Hep A is an inactive vaccine that stimulates the body’s natural immune system. This vaccine is recommended for all children, as well as for those in high-risk situations.

The vaccine is given in a series of two shots at six months apart.

It is recommended that children be given the first dose between 12-23 months of age, and the second dose six months later.

Once you have been either exposed to the HAV or given the vaccine, you will have antibodies to the virus for life. Immunity to HAV after the vaccine occurs about 2-4 weeks after the first injection, and the final injection results in life-long protection from the virus.

There is also a combo vaccine containing the hepatitis A and B viruses, that can be given to adults 18 years or older. This vaccine comes in the form of three shots over a period of six months.

For more about the vaccine. (link soon to come!)

Proper and frequent hand washing using soap and improved sanitation can help prevent spread of the virus

If you have the hepatitis A, you will want to take steps to reduce the risk of passing the virus on to others. These precautions include avoiding sexual activity, washing hands thoroughly after using the restroom, and not preparing food for others while you’re actively infected.

Stats in the US:

• Since 2007, there were an estimated 25,000 new cases of hepatitis A (this number may be much larger due to the large number of cases that go unreported due to symptom-less patients).²
• The vaccine was introduced into the United States in 1995. It dramatically reduced the rate of hepatitis A and the number of cases is currently the lowest it’s been in 40 years.²

Stats globally:

• There are an estimated1.4 million cases of hepatitis A every year.³
• Epidemics of hepatitis A occur sporadically, with a tendency for cyclic recurrences.³
• Hepatitis A outbreaks can lead to significant economic and social consequences in communities.
• Developing areas of the world with very poor sanitary conditions and hygienic practices have rates as high as 90% of children under 10 years old infected with HAV.³

 

 

Resources:

1. Melnick, JL. “Properties and Classification of Hepatitis A Virus.” Vaccine. 10 Suppl 1:S24-6. 1992. http://www.ncbi.nlm.nih.gov/pubmed/1335653
2. Centers for Disease Control and Prevention (CDC). www.cdc.gov
3. World Health Organization (WHO). www.who.int
4. Mayo Clinic. www.mayoclinic.org
5. Vaccines.gov. U.S. Department of Health and Human Services. www.vaccines.gov.
6. MedlinePlus. National Institutes of Health (NIH). U.S. National Library of Medicine. www.nlm.nih.gov/medlineplus

Pictures are Vaccine Mom original Art.