Changes in Toxoplasma diagnosis

The serological laboratory workload in detecting toxoplasma infection may be expected to change with changes in the clinical profile of patient populations. We have examined the clinical information and laboratory results for patients referred to the Scottish Toxoplasma Reference Laboratory in April-March 1999-2000 and 2009-2010. Numbers of patient sera submitted for testing were similar (1624 and 1552) but there was a change in the clinical profile, with a significant fall in patients with symptoms of current infection (612 versus 335; P<0.0001) and a significant rise in immunocompromised patients (275 versus 531; P<0.0001). Although the percentage of patient samples with toxoplasma antibody decreased (53.9% versus 37.5%; P<0.0001), the number of positives increased with age, demonstrating the continuing risk of toxoplasma infection. More cases of current infection were identified in 2009-2010 than in 1999-2000 (48 versus 35). This increase was significant both for all females with current infection (P=0.0253) and also for those in the childbearing 20-39 years age group (P=0.0388). Our literature search did not find any published information on toxoplasma workload in the last decade. In summary, we have shown that there have been significant changes in the laboratory diagnosis of toxoplasma infection but it is as important as ever that effective diagnostic strategies are maintained.