Surveillance of strongyloidiasis in Spanish in-patients (1998-2014)

Strongyloides stercoralis is a parasite that causes strongyloidiasis, a neglected tropical disease. S. stercoralis is a soil-transmitted helminth that is widely distributed in tropical and subtropical regions of the world. Strongyloidiasis can occur without any symptoms or as a chronic infection characterized by mild, unspecific symptoms such as pruritus, abdominal pain or discomfort; respiratory impairment also may manifest as a potentially fatal hyperinfection or disseminated infection. Most studies on strongyloidiasis in Spain have been related to chronic forms in immigrants or travellers from endemic zones and have mainly analysed out-patient populations. Studies of the impact of strongyloidiasis cases admitted to hospitals in Spain are lacking. Therefore, the aim of this study was to analyse the impact of strongyloidiasis in hospital care in Spain.

We designed a retrospective descriptive study using the Minimum Basic Data Set (MBDS, CMBD in Spanish) for inpatients with ICD-9: 127.2 (strongyloidiasis) diagnoses admitted to hospitals in the Spanish National Health System between 1998 and 2014.

A total of 507 hospitalizations with diagnosis of strongyloidiasis were recorded, 324 cases (63.9%) were males. The mean (±SD) age was 42.1±20.1 years. The impact of strongyloidiasis on the total population of Spain was 0.06 cases per 105 person-years, and the infection burden increased progressively over time (from 0.01 cases per 105 person-years in 1999 to 0.10 cases per 105 person-years in 2014). 40 cases (7.9%) died. The total cost was approximately €8,681,062.3, and the mean cost per patient was €17,122.4±97,968.8.

Our data suggest that strongyloidiasis is frequent in Spain and is increasing in incidence. Therefore, it would be desirable to improve the oversight and surveillance of this condition. Due to the fact that strongyloidiasis can be fatal, we believe that there is a need to establish risk categories for inclusion in national guidelines/protocols for screening individuals at risk of developing strongyloidiasis.