The viral genome of this retrovirus is complex, as it contains not only the gag, pol and env genes, but also genes that encode proteins that are not incorporated into the viral particle. These are termed bel-1 (tas) and bet. The function for bet is still unclear; however, it is known that the tas gene is a transactivator that plays a role in viral replication.
The way in which the virus replicates also differs from that of most retroviruses, as it may leave the cells via exocytosis using vesicles from the endoplasmic reticulum where some reverse transcription of the virus has taken place. Also, when reverse transcription happens late in viral replication, some particles produced contain DNA instead of RNA.
Humans are an accidental host for the virus (most people only become infected when exposed to it within the laboratory or from a monkey bite), so there are no known symptoms of this disease. To date, no human-to-human transmission has been documented.