Epidemiology and pathogenesis of Kaposi's sarcoma-associated herpesvirus

Kaposi's sarcoma (KS) occurs in Europe and the Mediterranean countries (cla ssic KS) and Africa (endemic KS), immunosuppressed patients (iatrogenic or post-transplant KS) and those with acquired immune deficiency syndrome (AID S), especially among those who acquired human immunodeficiency virus sexual ly (AIDS-KS). KS-associated herpesvirus (KSHV or HHV-8) is unusual among he rpesviruses in having a restricted geographical distribution. Like KS, whic h it induces in immunosuppressed or elderly people, the virus is prevalent in Africa, in Mediterranean countries, among Jews and Arabs and certain Ame rindians. Distinct KSHV genotypes occur in different I,arts of the world, b ut have not been identified as having a differential pathogenesis. KSHV is aetiologically linked to three distinct neoplasms: (i) KS, (ii) primary eff usion lymphoma, and (iii) plasmablastic multicentric Castleman's disease. T he histogenesis, clonality and pathology of the tumours are described, toge ther with tile epidemiology and possible modes of transmission of the virus .