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. 2020 Sep 21;9(1):133.
doi: 10.1186/s40249-020-00750-y.

Strongyloides stercoralis prevalence and diagnostics in Vientiane, Lao People's Democratic Republic

Somaphone Chankongsin  1   2 , Rahel Wampfler  2   3 , Marie-Therese Ruf  2   3 , Peter Odermatt  2   3 , Hanspeter Marti  2   3 , Beatrice Nickel  2   3 , Valy Keoluangkhot  1 , Andreas Neumayr  4   5   6
Affiliations

Strongyloides stercoralis prevalence and diagnostics in Vientiane, Lao People's Democratic Republic

Somaphone Chankongsin et al. Infect Dis Poverty. .

Abstract

Background: Despite the high prevalence of strongyloidiasis in the Laotian population, Laotian hospitals still lack diagnostic capacity to appropriately diagnose Strongyloides stercoralis infections. This cross-sectional hospital-based study was conducted to assess the prevalence of Strongyloides stercoralis infection among hospitalized patients treated at Mahosot Hospital, the primary reference hospital of Lao People's Democratic Republic (Lao PDR), and to validate feasible methods for diagnosing S. stercoralis infection at hospital's laboratory.

Methods: Between September and December 2018, stool samples of 104 inpatients were investigated for S. stercoralis infection by wet smear, Baermann technique, Koga Agar plate culture (KAPC), and real-time detection polymerase chain reaction (RTD-PCR) at the Infectious Diseases Ward of the Mahosot Hospital in Vientiane. The sensitivity, the specificity, the negative predictive value (NPV) of each diagnostic test, as well as their combination(s) was calculated using a composite reference standard (CRS). The correlation of the different test methods was assessed by chi-square or Fisher's exact test. Cohen's kappa coefficient was used to assess the diagnostic agreement of the different test methods.

Results: The overall prevalence of S. stercoralis infections among the study population was 33.4%. The cumulative infection prevalence statistically significantly increased from the lowest age group of 40 years and below (22.4%), to the medium (40.0%) and to the oldest age group of 61 year and above (72.7%)(P = 0.003). The cumulative infection prevalence of CRS was considerably higher in male (40.4%) compared to female patients (28.1%), but not statistically different (P = 0.184). The diagnostic sensitivity of Baermann technique, KAPC, RTD-PCR, and the combination of Baermann technique and KAPC were 60.0, 60.0, 74.3, and 77.1%, respectively. Only 13 patients (37.1%) of the total 35 S. stercoralis patients diagnosed with any technique had a simultaneously positive diagnostic test with Baermann, KAPC and RTD-PCR.

Conclusions: We identified Baermann technique and KAPC to be currently the most feasible and implementable standard methods for diagnosing S. stercoralis at a hospital setting such as Mahosot Hospital and provincial and district hospitals in Lao PDR and other low- and middle income countries in Southeast Asia.

Trial registration: This study was approved by the National Ethics Committee for Health Research in Lao PDR (reference no. 083/NECHR) and by the Ethics Committee Northwest and Central Switzerland (reference no. 2018-00594).

Keywords: Baermann method; Koga agar plate culture; Real time detection PCR; Strongyloides stercoralis; Strongyloidiasis; Wet smear.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Prevalence of Strongyloides stercoralis infection according to the testing method(s) used. Baermann: Baermann concentration technique; KAPC: Koga agar plate culture; RTD-PCR: Real-time detection polymerase chain reaction; Colours. Light grey, Single test applied; Grey, Cumulative prevalence of two tests; Dark grey, Cumulative prevalence of three tests combined
Fig. 2
Fig. 2
Positive test results for Strongyloides stercoralis grouped by diagnostic method. Baermann: Baermann concentration technique; KAPC: Koga agar plate culture; RTD-PCR: Real-time detection polymerase chain reaction
See this image and copyright information in PMC

References

    1. Albonico M, Becker SL, Odermatt P, Angheben A, Anselmi M, Amor A, et al. StrongNet: An International Network to Improve Diagnostics and Access to Treatment for Strongyloidiasis Control. PLoS Negl Trop Dis. 2016;10:e0004898. doi: 10.1371/journal.pntd.0004898. - DOI - PMC - PubMed
    1. Buonfrate D, Bisanzio D, Giorli G, Odermatt P, Fürst T, Greenaway C, et al. The global prevalence of Strongyloides stercoralis infection. Pathogens. 2020;9:468. doi: 10.3390/pathogens9060468. - DOI - PMC - PubMed
    1. Forrer A, Khieu V, Schär F, Hattendorf J, Marti H, Neumayr A, et al. Strongyloides stercoralis is associated with significant morbidity in rural Cambodia, including stunting in children. PLoS Negl Trop Dis. 2017;11:e0005685. doi: 10.1371/journal.pntd.0005685. - DOI - PMC - PubMed
    1. Vasquez-Rios G, Pineda-Reyes R, Pineda-Reyes J, Marin R, Ruiz EF, Terashima A. Strongyloides stercoralis hyperinfection syndrome: a deeper understanding of a neglected disease. J Parasit Dis. 2019;43:167–175. doi: 10.1007/s12639-019-01090-x. - DOI - PMC - PubMed
    1. Buonfrate D, Formenti F, Perandin F, Bisoffi Z. Novel approaches to the diagnosis of Strongyloides stercoralis infection. Clin Microbiol Infect. 2015;21:543–552. doi: 10.1016/j.cmi.2015.04.001. - DOI - PubMed

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