Friday, July 22, 2011

Hepatitis B


Hepatitis B is a contagious disease caused by hepatitis B virus (HBV), which calls for the liver of hominoids, including the infected people and caused inflammation leads to hepatitis. Originally called "serum hepatitis", is known to be epidemic in some parts of Asia and Africa has caused and is endemic in China. About a quarter of the world's population, more than 2 billion people are infected with hepatitis B virus were infected. This includes 350 million chronic carriers of the virus. Transmission of hepatitis B virus from exposure to infectious blood or body fluids such as semen and vaginal secretions, and viral DNA in saliva, tears and urine, respectively, from chronic carriers with high titers of serum DNA. Perinatal infection is an important mode of transmission in endemic (mainly developing) countries. Other risk factors for HBV infection include working in a medical facility, a blood transfusion and dialysis, acupuncture, tattoos, extended foreign travel and residence in an institution. However, hepatitis B virus is not transmitted through casual contact such as holding hands, sharing eating utensils or drinking glasses, breast, kissing, hugging, coughing or sneezing.
Acute illness causes liver inflammation, vomiting, jaundice and, rarely, death. Chronic hepatitis B may eventually lead to cirrhosis and liver cancer fatal disease with very poor response to current chemotherapy.
Infection can be prevented by vaccination.
Hepatitis B virus is a hepadnavirus with a HEPA-hepatotrophic and DNA, because this virus DNA and has a circular genome is partially double-stranded DNA. Virus RNA intermediate by reverse transcription to repeat, and in this respect they are similar to retroviruses. Although replication in the liver, the virus spreads into the blood, where virus-specific proteins and their corresponding antibodies are detected in infected people. Blood tests for these proteins and antibodies, which are used to diagnose infection.