Human tularemia in France, 2006-2010

Abstract

Background: Tularemia is an endemic but rare disease in France. We describe the epidemiologic, clinical, diagnostic, treatment, and prognostic aspects of the disease in 101 consecutive patients investigated during a 5-year period (2006-2010).

Methods: All tularemia cases confirmed at the French Reference Center for Tularemia (FRCT) were included. Data were collected both at the Institut de Veille Sanitaire (mandatory notification) and FRCT. Diagnostic methods included serological tests (microagglutination and indirect immunofluorescence assay), Francisella tularensis cultures, real-time polymerase chain reaction (RT-PCR) tests, and molecular identification of the F. tularensis subspecies involved.

Results: The patient cohort consisted of 55 men and 46 women (sex ratio, 1.2; average age, 51.7 years), including 93 sporadic cases that occurred throughout France. Contaminations occurred predominantly through contact with or ingestion of lagomorphs (31.7%), tick bites (10.9%), or contaminated environments (7.9%). The glandular and ulceroglandular forms predominated (57.5% of cases), but 18.8% of patients experienced a systemic disease and 29.7% were hospitalized. Specific diagnosis was mainly based on serology, but 38.6% of patients had positive RT-PCR tests and 20.8% had a positive culture. F. tularensis subspecies holarctica was identified in 25 patients. All patients except 1 recovered from infection, but 38.6% experienced relapses despite appropriate antibiotic therapy.

Conclusions: The epidemiological and clinical aspects of tularemia in France are varied, suggesting different modes of contamination. The high rates of systemic diseases and hospitalization indicate that the more serious cases are more likely to be diagnosed and notified. RT-PCR tests may help to improve diagnosis and reporting of the disease.