Hepatitis
SHepatitis (plural hepatitides) implies injury to liver characterised by presence of inflammatory cells in the liver tissue. Etymologically from ancient Greek hepar (?pa?) or hepato- (?pat?-) meaning 'liver' and suffix -itis denoting 'inflammation' (c.1727). The condition can be self limiting, healing on its own or can progress to scarring of the liver. Hepatitis is acute when it lasts less than 6 months and chronic when it persists longer. A group of viruses known as the hepatitis viruses cause most cases of liver damage worldwide. Hepatitis can also be due to toxins (notably alcohol), other infections or from autoimmune process. It may run a subclinical course when the affected person may not feel ill. The patient becomes unwell and symptomatic when the disease impairs liver functions that include, among other things, screening of harmful substances, regulation of blood composition, and production of bile to help digestion.

• Hepatitis A
Hepatitis A or infectious jaundice is caused by a picornavirus transmitted by the Fecal-oral route, often associated with ingestion of contaminated food or with anal/oral sex. It causes an acute form of hepatitis and does not have a chronic stage. The patient's immune system makes antibodies against hepatitis A that confer immunity against future infection.
According to Centers for Disease Control and Prevention, it is estimated there are between 125,000 and 200,000 total infections per year in the United States. It is estimated that 84,000 to 134,000 of the total infections will show symptoms of HAV. Each year, approximately 100 people will die because of hepatitis A.
Hepatitis A (HAV) is transmitted primarily through oral contact with feces (oral-fecal contact). This includes contaminated food or water sources and sexual contact, especially oral-anal sex.
Hepatitis A can easily spread among young children in day care settings because many are in diapers and cannot wash their own hands, and no one may know they have the disease since children normally do not have symptoms.
HAV has on rare occasions been transmitted through blood transfusion, use of blood products or sharing needles or other injecting equipment contaminated with HAV-infected blood. Transmission by blood is rare because the presence of virus in the blood occurs with the onset of infection and is not thought to be present long.
HAV is preventable by vaccination. The hepatitis A vaccine is made from inactive hepatitis A virus particles. The body reacts with the inactive virus to produce an antibody that protects against infection of the liver by the hepatitis A virus. Clinical trials have shown that the vaccine is effective in preventing infection in about 95% of people who were exposed.


• Hepatitis B
Hepatitis B is caused by a hepadnavirus, which can cause both acute and chronic hepatitis. Chronic hepatitis develops in the 15% of patients who are unable to eliminate the virus after an initial infection.
Chronic (long-lasting) hepatitis B can cause liver cell damage, which can lead to cirrhosis (scarring of the liver) and cancer. It is estimated that 5,000 people die each year in the United States due to the complications of cirrhosis and liver cancer as a result of HBV.
According to Centers for Disease Control and Prevention (CDC), it is estimated that 1.25 million people in the United States have chronic HBV. There were an estimated 73,000 new HBV infections in the United States in 2003.
Identified methods of transmission include blood (blood transfusion, now rare), tattoos (both amateur and professionally done), sexually (through sexual intercourse or through contact with blood or bodily fluids), or via mother to child by breast feeding (minimal evidence of transplacental crossing). However, in about half of cases the source of infection cannot be determined.
Blood contact can occur by sharing syringes in intravenous drug use, shaving accessories such as razor blades, or touching wounds on infected persons. Needle-exchange programs have been created in many countries as a form of prevention.
Hepatitis B is preventable through vaccination. Since hepatitis D can only coexist with hepatitis B, getting vaccinated against hepatitis B also protects you against hepatitis D.


• Hepatitis C
Hepatitis C (originally "non-A non-B hepatitis") is a liver disease caused by a virus with an RNA genome that is a member of the Flaviviridae family. It can be transmitted through contact with blood (including through sexual contact where the two parties' blood is mixed) and can also cross the placenta.

Hepatitis C is the most common chronic bloodborne infection in the United States. It is estimated that around 4 million Americans have been infected with hepatitis C, of whom 2.7 million have chronic infections. Each year, it is estimated that there are 30,000 new infections in the United States, according to the Centers for Disease Control and Prevention (CDC). Of those new infections, only 20% of those infected will have symptoms. That means many people will become infected with hepatitis C and not know it right away.

Hepatitis C is primarily transmitted by direct contact with blood. Hepatitis C can be spread by vaginal or anal sex, but this does not occur very often. Factors found to be associated with sexual transmission of HCV are: sex with multiple partners, presence of other STDs, or sex with trauma (for example, rough sex, rape, or sexual abuse). Hepatitis C may be passed from an infected mother to her baby. Neonatal transmission may occur at birth if the mother is infected.

Patients with hepatitis C are susceptible to severe hepatitis if they contract either hepatitis A or B, so all hepatitis C patients should be immunized against hepatitis A and hepatitis B if they are not already immune, and avoid alcohol. The virus can cause cirrhosis of the liver.

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