Borna disease virus and mental health: a cross-sectional study

Borna disease is an infectious neurological disease of horses, sheep and possibly other animals. A role for Borna disease virus (BDV) in human neurological and psychiatric illness has been proposed, but this hypothesis remains controversial.

To investigate the epidemiology of BDV in UK farming communities.

Retrospective cohort study.

We measured the seroprevalence of BDV in the PHLS Farm Cohort, a representative sample of those employed in agriculture in the UK, and investigated the clinical significance of our findings by comparing the prevalence of symptoms of neurotic psychopathology in those found seropositive and seronegative.

Seroprevalence was 2.3% (95%CI 1.3- 4.0%) in 1994, 3.1% in 1996 (95%CI 1.9-5.0%) and 2.6% in 1999 (95%CI 1.5%-4.6%). Those living or working on livestock farms had higher seroprevalence (2.6%) than those on mixed (2.3%) or arable (1.6%) farms, but this was not statistically significant. Exposure to horses, sheep and cats did not increase risk of seropositivity. Seropositives were no more likely to report symptoms of psychiatric morbidity.

UK farming populations appear to be exposed to Borna disease virus. However, we found no evidence that exposure to BDV was associated with morbidity in this healthy occupational cohort.