“…This observation led Davies to put forward the hypothesis that an arthropod-borne virus might play a part in the causation of the tumour (Burkitt, 1962). It is also known that there is a high incidence in New Guinea, which has a climate similar to that of tropical Africa (ten Seldam et al, 1966). However, cases have been identified in the U.S.A. and England (O'Conor et al, 1965 ;Dorfman, 1965;Wright, 1965).…”