Hepatitis B

Hepatitis B is an infectious inflammatory illness of the liver caused by the hepatitis B virus (HBV) that affects hominoidea, including humans. Originally known as "serum hepatitis", the disease has caused epidemics in parts of Asia and Africa, and it is endemic in China. About a third of the world population has been infected at one point in their lives, including 350 million who are chronic carriers.

The virus is transmitted by exposure to infectious blood or body fluids such as semen and vaginal fluids, while viral DNA has been detected in the saliva, tears, and urine of chronic carriers. Perinatal infection is a major route of infection in endemic (mainly developing) countries. Other risk factors for developing HBV infection include working in a healthcare setting, transfusions, and dialysis, acupuncture, tattooing, extended overseas travel and residence in an institution. However, Hepatitis B viruses cannot be spread by holding hands, sharing eating utensils or drinking glasses, kissing, hugging, coughing, sneezing, or breastfeeding.

The acute illness causes liver inflammation, vomiting, jaundice, and rarely, death. Chronic hepatitis B may eventually cause cirrhosis and liver cancer—a disease with poor response to all but a few current therapies. The infection is preventable by vaccination.

Hepatitis B virus is an hepadnavirus—hepa from hepatotropic (attracted to the liver) and dna because it is a DNA virus—and it has a circular genome of partially double-stranded DNA. The viruses replicate through an RNA intermediate form by reverse transcription, which practice relates them to retroviruses. Although replication takes place in the liver, the virus spreads to the blood where viral proteins and antibodies against them are found in infected people.

This text uses material from Wikipedia licensed under CC BY-SA

Latest Spotlight News

Study reveals nervous system's role in asthma attacks

(Medical Xpress)—Asthma is a debilitating condition that kills 250,000 people around the world each year. People with asthma have hyperreactive airways and thickened lung walls obstructed with mucus. During ...

Molecular basis of age-related memory loss explained

From telephone numbers to foreign vocabulary, our brains hold a seemingly endless supply of information. However, as we are getting older, our ability to learn and remember new things declines. A team of ...

Researchers discover neuroprotective role of immune cell

A type of immune cell widely believed to exacerbate chronic adult brain diseases, such as Alzheimer's disease and multiple sclerosis (MS), can actually protect the brain from traumatic brain injury (TBI) and may slow the ...

HIV pills show more promise to prevent infection

There is more good news about HIV treatment pills used to prevent infection in people at high risk of getting the AIDS virus: Follow-up from a landmark study that proved the drug works now shows that it does ...