The complete nucleotide sequence of the genome of a hepatitis B virus isolated from a naturally infected chimpanzee

The complete nucleotide sequence of a strain of hepatitis B virus, originally isolated from a naturally infected chimpanzee, has been determined. Interesting features of the sequence include the presence of an in-phase stop codon in the 'pre-core ' region of the core antigen open reading frame. The sequence shows approximately 109/oo nucleotide divergence from all of the other hepatitis B virus sequences previously published and the possibility that this divergence is the result of passage through chimpanzees is discussed. The occurrence of naturally acquired hepatitis B virus (HBV) infection in the colony of chimpanzees of the Zoological Society of London has been reported previously (Zuckerman et al., 1978). One of the animals, chimpanzee K, was persistently infected with a high titre of hepatitis B surface antigen (HBsAg), and was also positive for both hepatitis B e antigen (HBeAg) and circulating virus. The subtype of the surface antigen was adw. The mother of this animal died from natural causes in February, 1973, and we have been unable to test her serum. However, a female sibling was also HBsAg-positive and it is possible that both became infected perinatally. We describe here the cloning and sequencing of the genome of this virus