The EB virus in relation to infectious mononucleosis.

Chance favours the prepared mind and it was a fortunate circumstance that the Henles were studying the Epstein-Barr (EB) virus (Epstein, 1970) when one of their technicians, whose serum was being used as a negative control, fell ill with typical infectious mononucleosis. During this illness, she developed not only heterophile antibodies but also fluorescent antibodies to the EB virus (Henle, Henle, and Diehl, 1968). In another example of forethought, sera had been taken at intervals over the years from university students. Examination of these confirmed the association between the development of infectious mononucleosis and the acquisition ofantibodies to the EB virus (Evans, Niederman, and McCollum, 1968). Subsequent studies (Niederman, Evans, Subrahmanyan, and McCollum, 1970; Sawyer, Evans, Niederman, and McCollum, 1971, Joint Investigation by University Health Physicians and Public Health Laboratory Service Laboratories, 1971) have shown convincingly that fluorescent antibodies to the EB virus develop during illnesses which are clinically recognizable as infectious mononucleosis and which are associated with the development of a positive Paul-Bunnell test and the appearance of typical abnormal lymphocytes in the peripheral blood. Infectious mononucleosis which is unassociated with the development of a positive Paul-Bunnell test may be associated with cytomegalovirus infection (Klemola and Kaariiiinen, 1965; Lamb and Stern, 1966) but is uncommonly associated with EB virus infection (Klemola, von Essen, Henle, and Henle, 1970). The transmission of EB virus in man has been observed on several occasions. Grace, Blakeslee, and Jones (1969) inoculated serologically negative volunteers with cell extracts which contained EB virus: infectious mononucleosis developed in these individuals and they acquired EB virus antibodies. Accidental infection following perfusion with presumably infected blood has been described (Gerber, Walsh, Rosenblum, and Purcell, 1969) but Stevens and Pry (1971) considered this to be a rare event. Kapsenberg, Langenhuysen, Nieweg, and Deiss (1970) observed clinical infectious mononucleosis in a girl of 17 which followed a blood transfusion; she developed high levels of antibody to cytomegalovirus and also to EB virus. Spread of EB virus infection, with or without overt illness, has been detected in family and social contacts of children and young adults with infectious mononucleosis (Wahren, Lantorp, Sterner, and Espmark, 1970; Joncas and Mitnyan, 1970); the latter authors remarked upon the apparent low infectivity of this virus. To date, there have been no reports of the production of infectious mononucleosis in animals following the administration of EB virus, although Landon and Malan (1971) observed the decline of (probably) maternal antibodies in three species of