The United Nations designated 2013 the International Year of Water Cooperation.virus is associated with acute viral hepatitis, an illness that begins with general ill-health, loss of appetite, nausea, vomiting, body aches, mild fever, and dark urine, and then progresses to development of jaundice.A few people may have a more severe form of liver disease known as (fulminant hepatic failure) and may die as a result.The infection may be entirely asymptomatic and may go unrecognized.The incubation period of the hepatitis B virus is 75 days on average but can vary from 30 to 180 days.
The virus is one of the smallest enveloped animal viruses.
There are four known genes encoded by the genome, called C, X, P, and S.
The core protein is coded for by gene C (HBc Ag), and its start codon is preceded by an upstream in-frame AUG start codon from which the pre-core protein is produced.
The 42 nm virions, which are capable of infecting liver cells known as hepatocytes, are referred to as "Dane particles".
In addition to the Dane particles, filamentous and spherical bodies lacking a core can be found in the serum of infected individuals.