Hepatitis D viruses spread through exposure to blood and other bodily fluids, syringes and needles contaminated with blood and other bodily fluids, sexual transmission and, rarely, from infected mother to foetus.
D hepatiidi viirused levivad kokkupuutel vere ja muude kehavedelikega, nendega saastunud süstalde-nõeltega, sugulisel teel ja harva nakatunud emalt lootele.