Presentation on theme: "Cheryl Ryan Renee Baker. Hepatitis is the inflammation of the liver caused by a virus. The disease targets liver cells, hepatocytes. There are currently."— Presentation transcript:
Hepatitis is the inflammation of the liver caused by a virus. The disease targets liver cells, hepatocytes. There are currently eleven viruses recognized as causing hepatitis: 2 are herpesviruses 9 are hepatotropic ( 5 are well characterized: A, B, C, D, and E)
Taxonomy Hepatitis A Virus (HAV) - Picornaviridae, Hepatovirus Hepatitis B Virus (HBV) - Orthohepadnavirus, Hepodnaviridae Hepatitis C Virus (HCV) - Flaviviridae
Ecology of the Virus Biological vectors – humans, contaminated food and water, contaminated needles HAV- can live outside the body for months, depending on the environmental conditions. HBV - can survive outside the body at least 7 days. HCV- can survive outside the body and still transmit infection for 16 hours, but not longer than 4 days.
Infection Process- Hepatitis A HAV enters the gut replicates in the alimentary tract spreads to infect the liver multiplies in hepatocytes
Infection Process – Hepatitis B & C The virus attaches to the liver cell and is transported inside. Viral particles are released into the nucleus. The virus is replicated and then released from the cell.
Symptoms Jaundice Fatigue Abdominal pain Loss of appetite Nausea Diarrhea Fever Joint Pain ( HBV) Dark Urine (HCV)
Diagnostic Tests Serological testing – presence of IgM antibody to HAV Blood Tests (HBV and HCV)
Treatments HAV – vaccine is the best prevention HBV – vaccine HCV – there is no vaccine available Who should be vaccinated? Who should not be vaccinated?
Prevention Surest way to prevent transmission is to avoid sexual contact with infected persons. (HBV and HCV) Never inject illegal drugs. Do not share personal care items. Consider the risks of getting tattoos and piercings. Wash hands with soap and water after using the bathroom, changing a diaper, and before preparing and eating food. (HAV)
Epidemiology HAV – Before the vaccine became available there were 35,000 cases per year. Number of new hepatitis A cases: 5,683 (2004) Transmitted by fecal-oral contamination, sexual contact, illegal drug use, and consumption of contaminated food. As little as 10-100 viral particles are needed to infect the host. 1/3 have evidence of past infection. Hepatitis E is similar to Hepatitis A.
Epidemiology (cont.) HBV – Generally transmitted through body fluids and sexual contact, illegal drug use and needle sticks, and healthcare settings. As of 1997 more than 80 countries had adopted routine HBV vaccinations for children. The number of new infections per year declined from 260,000 in the 1980’s to about 60,000 in 2004. Hepatitis D only occurs when the host is infected with HBV. Estimated 1.25 million chronically infected Americans, of whom 20-30% acquire their infection in childhood.
Epidemiology (cont.) HCV – Transmission occurs when contaminated blood enters the body of a person who is not infected. Most infections are due to illegal injection drug use. Estimated 4.1 million (1.6%) of Americans have been infected with HCV. The number of new infections has declined from approximately 240,000 in the 1980’s to about 26,000 in 2004. Transfusion associated cases now occur in less than 1 per 2 million transfused units of blood.
Morbidity and Mortality HAV – There is no chronic infection. About 15% of people infected will have prolonged or relapsing symptoms over a 6-9 month period. HBV -Each year, approximately 600,000 deaths occur worldwide (2003). Death from chronic liver disease occurs in 15-25% HCV – 1-5% of infected persons die from chronic liver disease. Leading cause for liver transplants.
Latest Research Alpha Interferon which results in sustained remission in selected patients is the only available therapy for treatments of persons with chronic hepatitis C. Prevention of HCV infection by vaccination is likely to be challenging if ongoing viral mutations continue.