High prevalence of Strongyloides stercoralis among farm workers on the Mediterranean coast of Spain: analysis of the predictive factors of infection in developed countries.

Strongyloidiasis is a parasitosis characterized by persistent infection before dissemination and the development of potentially fatal disease. Since diagnosis is difficult, knowledge of the prevalence and geographic distribution of the disease is of practical importance. A study was made of Strongyloides stercoralis infection in a random and representative sample of farm workers in a tourist region in Spain based on the detection of larvae of triple stool samples. The prevalence of infection was 12.4% (95% confidence interval [CI] = 8.4-16.4). None of the 26 clinical or epidemiologic variables analyzed were found to be predictive of infection. Only eosinophilia (> 400 eosinophils/mm3) was significantly greater among the infected individuals (odds ratio = 73.4, 95% CI = 16.3-327.0), with a sensitivity of 93.5% and a specificity of 93.1%. A screening program is proposed to detect eosinophilia, to provide treatment without stool examinations, and thus afford a cost-effective policy for preventing the development of severe forms of the disease among specific risk groups where the prevalence of other parasitoses is low.

[Infection by Strongyloides stercoralis in the county of Safor, Spain]. / Infección por Strongyloides stercoralis en la comarca de La Safor (Comunidad Valenciana).

BACKGROUND: Strongyloides stercoralis is an endemic nematode in tropical and subtropical regions, but almost unknown in Spain. PATIENTS AND METHODS: In order to know some epidemiological, clinical and analytic features of this infection in our area (La Safor, Valencia), we performed a prospective study for 19 months. Through the search for the parasite in feces of patients with eosinophilia, we identified 37 subjects who were studied at diagnosis and 4 months later. RESULTS: Thirty-three patients (89%) were currently, or had been agricultural workers, and thirty had worked barefooted and/or had drunk contaminated irrigation water. Twenty-three patients (62%) had a chronic or immunosuppressive diseases, and two of them on steroid treatment, developed a disseminated strongyloidiasis. Thirteen patients (35%) were asymptomatic; the rest had clinical manifestations attributed S. stercoralis, mainly digestive. Two of the patients with disseminated strongyloidiasis also had concomitant bacterial infections by Streptococcus bovis, Streptococcus faecalis and Enterobacter sp. At diagnosis, besides eosinophilia, 86.5% had raised levels of IgE. Four months later treatment, the number of eosinophils was normal and IgE levels significantly decreased. The diagnostic yield of parasitic study of feces was increased with the number of samples examined. Thiabendazole achieved erradication of the parasite in 35 patients, and the other two died because of disseminated strongyloidiasis. CONCLUSIONS: The presence of eosinophilia in patients from rural areas with subtropical climate should raise suspicion about infection by S. stercoralis, which, although sometimes is asymptomatic, may cause systemic bacterial infections in cases of hyperinfestation, specially when glucocorticoid treatment is given.

[Strongyloides stercoralis infection in patients with bronchial obstructive pathology]. / Infección por Strongyloides stercoralis en pacientes con patología bronquial obstructiva.

Strongyloides stercoralis infection was hardly seen in Spain until a few years ago but has recently been shown to be fairly common in some geographic areas. In the respiratory tract this germ can cause acute bronchospasms that make diagnosis difficult, particularly in patients with underlying bronchial disease. To determine if curing S. stercoralis infection is accompanied by clinical and functional improvement in patients with bronchial obstruction, we studied the evolution of 22 infected patients: 11 with no bronchopulmonary disease and 11 with chronic airway obstruction or asthma. The following variables were assessed in both groups at the moment of diagnosis of infection and four months after cure: levels of eosinophils and total serum IgE, respiratory symptoms, steroid doses and spirometric parameters. After four months we observed a significant decrease in eosinophil (16 versus 5%) and IgE (1,600 versus 770 IU/ml) levels in both groups. The number of bronchospasms and daily steroid doses required decreased in the group with bronchial disease. No significant differences were seen in spirometric parameters, however. The improvement in respiratory symptoms, blood parameters and need for medication leads us to believe that airway inflammation decreases after the infection has been eradicated, in spite of the lack of improvement in bronchial obstruction.