Incidence of toxoplasmosis in patients with glandular fever and in healthy blood donors.

The differential diagnosis of the clinical syndrome of glandular fever may include Epstein-Barr virus, cytomegalovirus and Toxoplasma gondii infection. Some general practitioners and clinical laboratories choose to perform serological investigations for toxoplasmosis in all patients with glandular fever, who have negative Paul-Bunnell test results. The validity of this approach was assessed by a comparison of the incidence of toxoplasmosis in healthy blood donors and in a group of patients with clinically diagnosed glandular fever who had negative Paul-Bunnell tests. The results showed no significant difference in the frequency of acute or chronic toxoplasma infection between the two groups. In view of these findings, together with evidence of the lack of appropriate effective therapy for toxoplasmosis in immunocompetent individuals, and the dangers of failing to recognize concurrent severe disease of a separate aetiology, we recommend that Paul-Bunnell negative patients with clinically diagnosed glandular fever are not investigated for toxoplasmosis as a routine. However, these guidelines do not apply to patients at risk of severe sequelae from toxoplasma infection, notably pregnant women, who still require a full assessment.