Hepatitis D can be transmitted through blood, sexual contact, and percutaneous
incjection (IV drug users, hemopheliacs). Perinatal infection is rare. HDV is
seen worldwide, with more than 10 million people infected. Epidemics have been
observed in the Amazon Basin, the Mediterranean Basin and Central Africa, and
HDV spread by close contact is endemic to many Mediterranean countries, while in
the US it is for the most part confined to persons exposed to contaminated
blood.
A CDC map of HDV prevalence across the globe
From: Centers for Disease Control and Prevention (CDC), Atlanta, USA.