The epidemiology of infectious mononucleosis in Northern Scotland: a decreasing incidence and winter peak

Background: Infection with Epstein-Barr virus (EBV) is almost ubiquitous in humans and generally occurs at two ages: infantile, which is usually asymptomatic and associated with poorer socioeconomic conditions, and adolescent, which causes infectious mononucleosis (IM) in similar to 25% cases. The determinants of whether the infection causes IM remain uncertain. We aimed to evaluate seasonality and temporal trends in IM. Methods: Data from all Monospot tests, used as a marker for IM, were collected from the Grampian population over 16 years. Results: Positive Monospot test results peaked at 17 years in females and 19 in males. Females had 16% more diagnoses, although 55% more tests. IM was similar to 38% more common in winter than summer. The annual rate of positive tests decreased progressively over the study period, from 174/100 000 (95% CI 171-178) in 1997 to 67/100 000 ( 95% CI 65-69) in 2012. Conclusions: IM appears to be decreasing in incidence, which may be caused by changing environmental influences on immune systems. One such factor may be exposure to sunlight. Words 168.