High Prevalence of Strongyloidiasis in Spain: A Hospital-Based Study

Strongyloidiasis is a prevailing helminth infection ubiquitous in tropical and subtropical areas. However, prevalence data are scarce in migrant populations. This study aims at evaluating the prevalence of S. stercoralis at hospital level in migrant populations or long term travellers being attended in out-patient and in-patient units as part of a systematic screening implemented in 6 Spanish hospitals. A cross-sectional study was conducted and systematic screening for S. stercoralis infection using serological tests was offered to all eligible participants. The overall seroprevalence of S. stercoralis was 9.04% (95% confidence interval [95%CI] 7.76 −10.31). The seroprevalence of people with a risk of infection acquired in Africa and Latin America was 9.35% (95%CI 7.01-11.69), 9.22% (7.5-10.93), respectively. The number of individuals coming from Asian countries was significantly smaller and the overall prevalence in these countries was 2.9% (95%CI −0.3; −6.2). There was only one case (1/14 (7.14%) from an individual from East European countries. The seroprevalence in units attending potentially immunosuppressed patients was significantly lower (5.64%) compared with the seroprevalence in other units of the hospital (10.20%) or Tropical diseases units (13.33%) (p<0.001). Conclusions: We report a hospital-based systematic screening of strongyloidiasis with a seroprevalence of almost 10% in a mobile population coming from endemic areas suggesting the need of implementing strongyloidiasis screening in hospitalized patients coming from endemic areas, particularly if they are at risk of immunosuppression. Author summary Strongyloidiasis is an infection caused by the helminth Strongyloides stercoralis which is ubiquitous in tropical and subtropical areas. In the rest of the countries, it is also frequent in migrants coming from tropical and subtropical areas. The disease is more severe when an infected subject has an impaired immune system. Within this study we have evaluated the prevalence of this infection in people being attended in six Spanish hospitals. The prevalence was around 9%, being higher in Africa and Latin America compared with other regions. In addition, the prevalence in patients with an impaired immune system (immunosuppression) was lower compared with people non suffering immunosuppression. These results suggest that the prevalence of strongyloidiasis is quite high among migrants living in Spain and that a screening programme should be designed, particularly in immunosuppressed patients that are at more risk of suffering severe complications of the infection.