The decline of autochthonous leprosy in the Valencia Region of Spain: patterns and trends 1940–2015

Summary
Objectives: The aim of this study was to describe the patterns and trends of autochthonous leprosy in the Valencia Region (Spain).
Methods: We included all new leprosy cases originating from the Valencia Region between the years 1940 and 2015. Patients originating from other countries or other Spanish regions were excluded. New cases were analysed by age, sex, clinical type, occupation, and geographic distribution.
Results: A total of 442 patients with presumably autochthonous leprosy were included. Incidence rates consistently declined over the study period. Mean age at onset gradually increased from 34·2 years during the period 1940–1949 to 59·5 years during 2000–2015. There were no cases with clinical onset after 2006 and no cases born after 1973. Patients were predominantly males (57·7%) and 85·4% had multibacillary leprosy. The proportion of multibacillary cases increased gradually after 1970. The majority of male patients (67·9%) worked in agriculture. Most of the cases, especially during the later periods, were concentrated in the coastal regions.
Conclusions: Our findings are consistent with trends described in other regions with declining leprosy incidence rates and suggest that the transmission of M. leprae infection in this area may well have now stopped. Autochthonous leprosy in this region has had a male predominance and a high proportion of multibacillary cases. The geographic distribution and the high incidence in agricultural workers suggest that environmental factors should be further explored.