Populations at risk for alveolar echinococcosis, France

Abstract

During 1982-2007, alveolar echinococcosis (AE) was diagnosed in 407 patients in France, a country previously known to register half of all European patients. To better define high-risk groups in France, we conducted a national registry-based study to identify areas where persons were at risk and spatial clusters of cases. We interviewed 180 AE patients about their way of life and compared responses to those of 517 controls. We found that almost all AE patients lived in 22 départements in eastern and central France (relative risk 78.63, 95% CI 52.84-117.02). Classification and regression tree analysis showed that the main risk factor was living in AE-endemic areas. There, most at-risk populations lived in rural settings (odds ratio [OR] 66.67, 95% CI 6.21-464.51 for farmers and OR 6.98, 95% CI 2.88-18.25 for other persons) or gardened in nonrural settings (OR 4.30, 95% CI 1.82-10.91). These findings can help sensitization campaigns focus on specific groups.

Keywords: Echinococcus multilocularis; France; agricultural workers diseases; alveolar echinococcosis; communicable disease prevention and control; epidemiology; parasites; risk factors; rural health; zoonoses.

Figure 1

Location of patients, controls, and areas in France where persons are at risk for alveolar echinococcosis. The main area for human risk is located in eastern France and includes the départements (second largest administrative areas in France) where persons are at risk for alveolar echinococcosis of clusters 1, 2, and 4 as defined by SatScan analysis (Kulldorff, Boston, MA, USA; and Information Management Services, Inc., Rockville, MD, USA). Clusters 3 and 5 are located in the mountains of Massif Central and constitute the second area where persons are at risk.

Figure 2

Significant results by multivariate analysis using classification and regression tree analysis to determine risk for alveolar echinoccosis in France, 1982–2007. Black indicates patients; gray indicates controls; class number is enclosed in a square. When the last step of analysis was not significant, terminal classes were aggregated at the upper level. Patients appeared predominant in 4 terminal classes: class 1 represented persons who live in an urban (or semiurban) environment in a département (second largest administrative area in France) where persons are at risk for alveolar echinococcosis (DAR) and do not have a kitchen garden, class 2, persons who live in similar areas but have a kitchen garden; class 3, nonfarmers who live in rural areas in a DAR; and class 4, farmers who live in the same environment; class 5, mostly persons who live in départements (second largest administrative areas in France) where humans are not at risk.