INFECTIOUS MONONUCLEOSIS

INFECTIOUS MONONUCLEOSIS is a disease which, because of its various clinical manifestations in adolescence and young adUlts, may imitate a number of other infections. Conversely, there is always a temptation to label a febrile disease with otherwise undiagnostte features with the title of infectious mononucleosis. The Paul·Bunnell test for heterQPhil antibody remains an important test in the diagnosis of infectious mononucleosis. Unfortunately, in childhood infections it often fails to become positive and this is also occasionally the case in classical disease in young adults. With the relatively recent discovery of the EB (Epstein·Barr) virus, a further marker has become available to study the epidemiology of this disease. A number of excellent prospective studies have shed light on childhood mteetions with the EB virus. In the Cleveland family study, it was found that EB virus infections in childhood were rarely associated with obvious symptoms and signs which would suggest a clinical diagnosis of infectious mononucleosis.' Most cases of non-bacterial tonsillitis or pharyngitis were found to be due to other viruses, often adenoviruses. In the Alaskan Islands survey, 100% of primary infections were found to occur in children under the age of three years, but no distinctive clinical illness was observed.· It is possible, therefore, that some of the children with clinical infectious mononucleosis described by Hubble and his co-authors in this issue (page 863) were suffering from infections with viruses other than the EB virus. Hubble et alii, in their retrospective study in perth, have confirmed many of the well-known features of this illness. Two peaks of infection, one in the under ten years age group and another between the ages of 15 and 24 years have been well documented, the first perhaps representing early childhood infections acquired from the lPatient's mother. The earlier peak amongst adolescent females is also well described and perhaps attributable to earlier sexual maturity. Estimates of the crude annual incidence of heterophil antibody-positive infectious mononucleosis in general populations have ranged widely, and are clearly dependent u.pon the type of patients studied and the method of reporting.' It is of interest that the Western Australia group have been unable to confirm the seasonal incidence of the disease reported by other workers. Such differences, if present, might have been revealed by the study of a more precisely defined population over a longer period