Hepatitis A Hepato means Liver in Greek!

A bit about Hep A Family is Picornaviradea Non-enveloped (capsid) + sense RNA strand Causes an acute infection of the liver, symptoms can be noticed about 2 weeks after infection. Spread by fecal-oral route, sexual contact, or or contaminated food or water.

Areas of the world where viral infection is prevalent due to unsanitary conditions.

Breakdown of transmissions by CDC Approximately 100 people will die from Hep A in the US each year. 100, ,000 people in the US are infected each year.

Hep A symptoms develop about 2 weeks after infection – Nausea Nausea – Vomiting – Diarrhea, especially in children Diarrhea – Low-grade feverfever – Loss of appetite – Rash Rash – Tiredness, fatigue Tirednessfatigue – Jaundice - A yellow discoloration of the skin and the whites of the eyes Jaundice – Urine is dark brownish in color, like cola or strong tea. Urine – Pain in area of liver - On the right side of the abdomen, just under the rib cage Painrib cage

Jaundice: A build up of Bilirubin Yellowing of the eyes Jaundice of the skin can be treated with phototherapy. Sunlight breaks down bilirubin. Bilirubin crystals in the urine of an infected patient with Hepatitis. Usually, bilirubin is phagocytized by white blood cells.

Viral Reproduction Same as Rhinovirus. Since the nucleic acid is (+) sense RNA, after entering the cell by docking and causing a conformational change to the membrane to release the RNA, the RNA becomes an instant mRNA and reproduces in a vesicle. This virus doesn’t reproduce hugely in the small intestines because it is actually looking for a free ride to the liver! Once in the liver, large numbers of virus will be made and apoptosis of liver cells will occur.

Evading Host Defenses Virus in the intestinal cells is sent to lower layer M cells for “sampling”. An infection is detected by the M cells. Cytokines are released for antibody response. The virus is sent to the lymph nodes, where B cells create an antibody that will attach to the virus. The B cells go back to the intestines with IgA antibodies in full force. IgA can escort the virus out through feces. However…….

The virus knows how to IgA’s Weakness! IgA-virus complex is sent to the lymph nodes, then the blood to travel to the liver for destruction. The LIVER is where Hep A wanted to go all along! Liver cells (hepatocytes) have receptors for IgA antibodies and can help destroy viruses- except for the Hepatitis viruses.

How to return to the small intestine Newly released viruses travel along the bile duct that is connected to the small intestines. The bile duct generally sends bile salts to help digest fats in the SI.

How can the immune system fight off viruses in the hepatocytes? The adaptive immune system has to start all over again after liver cell death triggers the immune response. B cells have to start releasing IgG antibodies and killer T cells swoop in and destroy liver cells with the wrong antigens. The liver response is about a two week process.

IgM takes care of blood viruses (viremia), and IgG takes care of viruses in tissues. Note that as infection time increases, so does the IgG antibody production. Liver damage is apparent about 4 weeks post infection

Vaccinations are available worldwide Who should get hepatitis A vaccine? Persons 1 year of age and older traveling to or working in countries with high or inter mediate prevalence of hepatitis A, such as those located in Central or South America, Mexico, Asia (except Japan), Africa, and eastern Europe. For more information see Children and adolescents through 18 years of age who live in states or communities where routine vaccination has been implemented because of high disease incidence. Men who have sex with men. Persons who use street drugs. Persons with chronic liver disease. Persons who are treated with clotting factor concentrates. Persons who work with HAV-infected primates or who work with HAV in research laboratories.