External quality assurance scheme for diphtheria diagnostics 2012

Effective control of an uncommon vaccine-preventable disease is dependent upon prompt and early recognition and diagnosis. It is often difficult to diagnose diphtheria clinically, particularly in those countries where the disease is rarely seen. Diphtheria is often confused with other conditions, such as severe streptococcal sore throat, Vincent's angina, or glandular fever. Therefore, accurate microbiological diagnosis is crucial and complementary to clinical diagnosis. It is fundamental that EU Member States have the capacity and ability to undertake the procedures relating to the microbiological diagnosis of not only diphtheria but also the related infections caused by all potentially toxigenic strains of corynebacteria. ECDC has a role in building and developing microbiology laboratory networks; in 2010, the responsibility for the activities of the European Diphtheria Surveillance Network (EDSN) was transferred to ECDC. This report comprises the findings of the second EQA dispatch for the laboratory diagnosis of diphtheria under the auspices of EDSN. A total of thirty countries participated in this EQA and were asked to isolate, identify and perform toxigenicity testing on any Corynebacterium spp. present in the six simulated throat specimens sent. Key findings are listed below; a description of the work involved and the outcomes of these exercises are detailed [...] in this report.