Strongyloides stercoralis in Swiss dogs – a retrospective study suggests an  increasing occurrence of this potentially zoonotic parasite as a consequence of dog imports

Strongyloides stercoralis serology is a sensitive method for strongyloidiasis diagnosis, but it is prone to cross-reactions with other helminthiases. This four-year retrospective study aimed at estimating the performance of the Bordier IVD® Strongyloides ratti ELISA assay in a non-endemic country (France). The study included all patients tested for strongyloidiasis in our center between 2015 and 2019, by both serology and stool examination. Cases were defined using an algorithm considering serological results, microscopic examination of stools, and other biological, clinical or epidemiological data. The study included 805 stools from 341 patients (70% migrants, 20% travelers, 10% without travel to a highly endemic area). Thirty patients (8.8%) had positive serology, 9 had microscopically proven strongyloidiasis, and 11 and 10 were classified as probable and possible strongyloidiasis, respectively. Performances of microscopy and serology were compared, considering proven and probable strongyloidiasis as true infections. The sensitivity, specificity, positive predictive value and negative predictive value of serology were 100%, 97%, 67% and 100%, respectively, and those of microscopic examination of stools were 45% (p < 0.01), 100% (p < 0.01), 100% (p = 0.079) and 96% (p < 0.001), respectively. Eosinophilia did not help in discriminating true-positive from false-positive results. Overall, these results underline the high value of the S. stercoralis serologic assay, compared to stool examination. The systematic use of this technique for screening purposes in travelers or migrants, or before onset of immunosuppressive therapy, could help to improve patient management and epidemiological knowledge.

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Strongyloidiasis in Southern Alicante (Spain): Comparative Retrospective Study of Autochthonous and Imported Cases

Pathogens ◽

10.3390/pathogens9080601 ◽

2020 ◽

Vol 9 (8) ◽

pp. 601

Author(s):

Ana Lucas Dato ◽

María Isabel Pacheco-Tenza ◽

Emilio Borrajo Brunete ◽

Belén Martínez López ◽

María García López ◽

...

Keyword(s):

Retrospective Study ◽

Positive Culture ◽

Strongyloides Stercoralis ◽

Agricultural Activity ◽

Systematic Screening ◽

Screening Programs ◽

Imported Cases ◽

Advanced Stages ◽

Vega Baja ◽

Epidemiological Characteristics

Background: Strongyloidiasis is a parasitic disease with global prevalence. In Spain, autochthonous cases are concentrated in the Mediterranean basin. We aimed to analyze clinical and epidemiological characteristics of Strongyloides stercoralis infection in Vega Baja del Segura (Spain), comparing autochthonous versus imported cases. Methods: Observational retrospective study of all strongyloidiasis cases from January 2009 to January 2019. Cases were diagnosed by stool larvae visualization, positive culture, PCR, Strongyloides serology, and/or compatible histology. Results: We included 36 patients (21 men) with a mean age of 60.8 years ±17.6; 15 cases were autochthonous and 21 imported 80.9% from Latin America. Autochthonous cases were associated with older age (mean 71.3 vs. 53.3 years; p = 0.002), male sex (odds ratio (OR) 5.33; 95% confidence interval (CI) 1.15–24.68; p = 0.041), and agricultural activity (OR 13.5; 95% CI 2.4–73.7; p = 0.002). Fourteen were asymptomatic, three autochthonous cases presented with hyperinfection syndrome, and two patients died. There was no difference between autochthonous versus imported origin in eosinophilia at diagnosis (93.3% vs. 75%; p = 0.207), treatment received, or clinical response (85.7% vs. 88.9% cured; p = 1). Conclusion: In our region, imported strongyloidiasis coexists with autochthonous cases, which are mainly in older male farmers who are diagnosed at more advanced stages. Systematic screening programs are needed.

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A retrospective study comparing agar plate culture, indirect immunofluorescence and real-time PCR for the diagnosis of Strongyloides stercoralis infection

Parasitology ◽

10.1017/s0031182016002559 ◽

2017 ◽

Vol 144 (6) ◽

pp. 812-816 ◽

Cited By ~ 21

Author(s):

DORA BUONFRATE ◽

FRANCESCA PERANDIN ◽

FABIO FORMENTI ◽

ZENO BISOFFI

Keyword(s):

Retrospective Study ◽

Real Time ◽

Screening Method ◽

Agar Plate ◽

Strongyloides Stercoralis ◽

Rt Pcr ◽

Confirmatory Tests ◽

Reasonable Approach ◽

Proper Diagnosis ◽

Stool Samples

SUMMARYStrongyloides stercoralis is a parasite that can cause death in immunocompromised people. A proper diagnosis is hence essential. The real-time polymerase-chain reaction (RT–PCR) is a novel, promising diagnostic method, that detects the DNA of the parasite in stool samples. In this retrospective study, we compared the sensitivity of agar plate coproculture (APC), an in-house immunofluorescence test (IFAT) and an in-house RT–PCR for the diagnosis of S. stercoralis infection. The study sample was composed by 223 samples. Samples resulting positive to APC, IFAT and RT–PCR were 20, 140 and 25, respectively. When sensitivity was calculated against a composite reference standard, serology confirmed the best performance (sensitivity 95%), followed by RT–PCR (57%) and APC (45%). In conclusion, in a non-endemic setting, serology is the best screening method, while the combination of APC and RT–PCR does not seem a reasonable approach to increase sensitivity. Both methods can have a role as confirmatory tests for selected cases.

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