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Observations on the presence of immunity in rats to Angiostrongylus cantonensis (Chen)

Ow Yang CK, Lim BL, Lie Kian Joe

Med J Malaya, 1965 Sep;20(1):70.
PMID: 4221428
Matched MeSH terms: Strongyloidiasis/immunology*
Lateral Flow Dipstick Test for Serodiagnosis of Strongyloidiasis

Yunus MH, Arifin N, Balachandra D, Anuar NS, Noordin R

Am J Trop Med Hyg, 2019 08;101(2):432-435.
PMID: 31218996 DOI: 10.4269/ajtmh.19-0053

The conventional method of detecting Strongyloides stercoralis in fecal samples has poor diagnostic sensitivity. Detection of Strongyloides-specific antibodies increases the sensitivity; however, most tests are ELISAs that use parasite extract which may cross-react with the sera of other helminth infections. To improve the serological diagnosis of strongyloidiasis, this study aimed at developing a sensitive and specific lateral flow rapid dipstick test. Two recombinant proteins, recombinant NIE (rNIE) and recombinant Ss1a (rSs1a), were used in preparing the dipstick, with gold-conjugated antihuman IgG4 as detector reagent. In parallel, the corresponding ELISA was performed. Both assays demonstrated diagnostic sensitivity of 91.3% (21/23) when tested with serum samples of patients with Strongyloides infection, and 100% specificity with 82 sera of asymptomatic (healthy) and those with other parasitic infections. The ELISA and dipstick test results were positively correlated to each other (r = 0.6114, P = 0.0019). The developed lateral flow dipstick test may improve the serodiagnosis of strongyloidiasis and merit further validation studies.

Matched MeSH terms: Strongyloidiasis/immunology
Fulltext Laboratory detection of strongyloidiasis: IgG-, IgG4 - and IgE-ELISAs and cross-reactivity with lymphatic filariasis

Norsyahida A, Riazi M, Sadjjadi SM, Muhammad Hafiznur Y, Low HC, Zeehaida M, et al.

Parasite Immunol., 2013 May-Jun;35(5-6):174-9.
PMID: 23448095 DOI: 10.1111/pim.12029

Enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of IgG, IgG4 and IgE antibodies against Strongyloides stercoralis. A commercial ELISA (IVD Research, USA) was also used, and the sensitivities and specificities of the four assays were determined. Serum samples from 26 patients with S. stercoralis infection and 55 patients with other infections or no infection were analysed. Sensitivities of the IgG4 , IgG, IgE and IgG (IVD) assays were 76.9%, 84.6%, 7.7% and 84.6%, respectively, while the specificities were 92.7%, 81.8%, 100% and 83.6%, respectively. If filariasis samples were excluded, the specificities of the IgG4 -ELISA and both IgG-ELISAs increased to 100% and 98%, respectively. A significant positive correlation was observed between IgG- and IgG4 -ELISAs (r = 0.4828; P = 0.0125). IgG- and IgG- (IVD) ELISAs (r = 0.309) were positively correlated, but was not significant (P = 0.124). Meanwhile there was no correlation between IgG4 - and IgG- (IVD) ELISAs (r = 0.0042; P = 0.8294). Sera from brugian filariasis patients showed weak, positive correlation between the titres of antifilarial IgG4 and the optical densities of anti-Strongyloides IgG4 -ELISA (r = 0.4544, P = 0.0294). In conclusion, the detection of both anti-Strongyloides IgG4 and IgG antibodies could improve the serodiagnosis of human strongyloidiasis. Furthermore, patients from lymphatic filariasis endemic areas who are serologically diagnosed with strongyloidiasis should also be tested for filariasis.

Matched MeSH terms: Strongyloidiasis/immunology*
Fulltext Diagnostic Potential of an IgE-ELISA in Detecting Strongyloidiasis

Ahmad H, Balachandra D, Arifin N, Nolan TJ, Lok JB, Hayat Khan A, et al.

Am J Trop Med Hyg, 2020 12;103(6):2288-2293.
PMID: 32996454 DOI: 10.4269/ajtmh.20-0265

Strongyloides stercoralis infection is prevalent worldwide and can cause lifelong infection in immunocompetent individuals, and potentially death in immunosuppressed patients. The diagnosis is hindered by the low sensitivity of microscopic examination, thus making serology an important complementary test to improve the detection rate. However, there were reports that some Strongyloides-infected individuals were negative with specific IgG and IgG4 assays, and other helminth infections were positive with commercial Strongyloides IgG-ELISAs. Thus, there is a need to develop better serodiagnostic methods for strongyloidiasis. We investigated the diagnostic potential of IgE-ELISAs using Strongyloides larval lysate. Sera from two groups infected with Strongyloides served as the positive reference, that is, 1) positive by commercial IgG-ELISAs and IgG4 rapid test, and stool samples positive by microscopy and/or PCR (group IA; n = 20); and 2) negative by IgG-ELISAs and IgG4 rapid test, but stool samples were PCR positive (group IB sera; n = 11). Sera from another two groups served as negative reference (controls), that is, 1) infected with other parasites (group II; n = 73) and 2) healthy donors (group III; n = 22). Results showed a 100% diagnostic sensitivity in detecting sera from groups IA and IB. The latter group of individuals probably had early infection because their IgG and IgG4 assays were negative. The optical density values of group IB sera were also significantly lower than those of group IA (P < 0.003). The IgE-ELISA was 100% specific when tested against sera from groups II and III. This study highlights the diagnostic potential of IgE-ELISA using larval lysate to detect strongyloidiasis, especially those with probable early infection.

Matched MeSH terms: Strongyloidiasis/immunology
Fulltext Seroprevalence of fascioliasis, toxocariasis, strongyloidiasis and cysticercosis in blood samples diagnosed in Medic Medical Center Laboratory, Ho Chi Minh City, Vietnam in 2012

Nguyen T, Cheong FW, Liew JW, Lau YL

Parasit Vectors, 2016 09 05;9(1):486.
PMID: 27595647 DOI: 10.1186/s13071-016-1780-2

BACKGROUND: Despite the global effort against neglected tropical diseases (NTDs), developing countries with middle to low income are still burdened by them. Vietnam has been undergoing substantial economic growth and urbanization, but underprivileged people living in rural and suburban areas are still having little access to public health infrastructure and proper sanitation. Hitherto, limited information is available for seroprevalence and risk factors of several parasitic diseases in Vietnam.
METHODS: A retrospective study was performed on diagnostic results of Fasciola spp., Toxocara spp., Strongyloides stercoralis and Taenia solium IgG ELISA tests from Medic Medical Center Laboratory, Ho Chi Minh City in 2012. The data were first stratified before statistical analyses were performed. Seroprevalence of fascioliasis, toxocariasis, strongyloidiasis and cysticercosis was determined and the age and gender risk factors were evaluated.
RESULTS: Seroprevalence of fascioliasis, toxocariasis, strongyloidiasis and cysticercosis was 5.9 % (590/10,084; 95 % CI: 5.44-6.36), 45.2 % (34,995/77,356; 95 % CI: 44.85-45.55), 7.4 % (3,174/42,920; 95 % CI: 7.15-7.65) and 4.9 % (713/14,601; 95 % CI: 4.55-5.25), respectively. Co-exposure to multiple parasites was detected in 890 males (45.7 %; 95 % CI: 43.49-47.91) and 1,059 females (54.3 %; 95 % CI: 52.09-56.51). Social structure and differences in behavioural factors caused the gender factor to have a significant effect on the prevalence of all the diseases, while the seropositivity for fascioliasis and strongyloidiasis were age group-related.
CONCLUSIONS: The seroprevalence of fascioliasis, toxocariasis, strongyloidiasis and cysticercosis in the blood samples diagnosed in Medic Medical Center Laboratory, Ho Chi Minh City, in year 2012 were comparatively high. The Vietnamese customs and cultures, dietary habits and agricultural practices exposed them to high risk of contracting NTDs. Despite the possibility of false positive results due to antigenic cross-reactions, detection of IgG antibodies remains as a reliable method in sero-epidemiological study as it is non-invasive and demonstrates previous exposure of individuals to the parasites. Besides the implementation of strategies to control these diseases, epidemiological analysis and surveillance of diseases should also be continually strengthened to monitor the effectiveness of regimens and interventions.

Matched MeSH terms: Strongyloidiasis/immunology