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 shows cultural images may hinder proficiency in second language skills
(Medical Xpress)—A team of combined researchers from Columbia Business School and Singapore Management University has found that people who have learned a second language become less proficient at speaking ...
Inside each of us is our own internal timing device. It drives everything from sleep cycles to metabolism, but the inner-workings of this so-called "circadian clock" are complex, and the molecular processes behind it have ...
The discerning fruit fly: Linking brain-cell activity and behavior in smell recognition
Behind the common expression "you can't compare apples to oranges" lies a fundamental question of neuroscience: How does the brain recognize that apples and oranges are different? A group of neuroscientists ...
Recent research has shown that cancer cells have a much different – and more complex – metabolism than normal cells. Now, scientists at The University of Texas at Dallas have found that exploiting these differences might ...
Researchers have discovered and mapped the signaling network between two previously unconnected proteins, exposing a link that, if broken, could cut off cancer cell growth at its starting point.
Men who lose sleep during the work week may be able to lower their risk of developing Type 2 diabetes by getting more hours of sleep, according to Los Angeles Biomedical Research Institute (LA BioMed) research findings presented ...
Aspirin is known to lower risk for some cancers, and a new study led by a UC San Francisco scientist points to a possible explanation, with the discovery that aspirin slows the accumulation of DNA mutations in abnormal cells ...
Balancing act: Mitochondrial protein coordinates a little-known enzyme that controls how fat is stored or burned
(Medical Xpress)—Calories in, calories out. Any dieter is familiar with the two sides of the equation for weight loss, usually reduced to eating less and exercising more. But what controls the body's balance ...
The rhythm of everything
Dawn triggers basic biological changes in the waking human body. As the sun rises, so does heart rate, blood pressure and body temperature. The liver, the kidneys and many natural processes also begin shifting ...
The link between genes and cancer
(Medical Xpress)—When people think about genes and their relationship to cancer, most probably think about a person's hereditary cancer risk, especially after Angelina Jolie's recent news about her inherited ...
