Strongyloides stercoralis in type 2 diabetes mellitus: discordant stool and serologic findings in an endemic Brazilian population.

BackgroundStrongyloides stercoralis is an intestinal parasite that can cause chronic infection, hyperinfection and/or a dissemination syndrome in humans. The use of techniques targeting ova fails to detect S. stercoralis, as only larvae of the parasite are excreted in faeces. Due to the absence of “Gold” standard diagnostic method for S. stercoralis, there is a paucity of reported data worldwide.ObjectiveThis study aimed to evaluate the performance of diagnostic methods of S. stercoralis infection by taking the composite reference as a “Gold” standard.MethodsA cross-sectional study was conducted among 844 schoolchildren in Amhara Region, Ethiopia, from April to December 2019. Stool samples were collected and processed with formol-ether concentration technique (FECT), spontaneous tube sedimentation technique (STST), Baermann concentration technique (BCT), agar plate culture (APC) and real-time polymerase chain reaction (RT-PCR). Sensitivity, specificity, positive predictive value, and negative predictive value of each diagnostic method were computed against the composite reference. The agreements of diagnostic methods were evaluated by Kappa value at 95% CI.ResultsThe composite detection rate of S. stercoralis by the five diagnostic methods was 39.0% (329/844). The detection rate of the parasite from stool samples by FECT, STST, BCT, APC and RT-PCR was 2.0% (17/844), 4.0% (34/844), 10.2% (86/844), 10.9% (92/844) and 28.8% (243/844), respectively. The highest detection rate (37.8%; 319/844) of S. stercoralis was recorded by a combination of BCT, APC, and RT-PCR followed by a combination of STST, BCT, APC and RT-PCR (37.3%; 315/844). The sensitivity of FECT, STST, BCT, APC and RT-PCR against the composite reference was 5.2%, 10.3%, 26.4%, 28.0% and 73.9%, respectively. The diagnostic agreements of RT-PCR, APC, BCT, STST and FECT with the composite reference in detection of S. stercoralis were substantial (0.775), fair (0.321), fair (0.305), slight (0.123), and slight (0.062), respectively.ConclusionRT-PCR detected the highest number of S. stercoralis infections. A combination of RT-PCR with APC and/or BCT better detected S. stercoralis from stool samples compared to other combinations or single diagnostic methods. Therefore, RT-PCR and combination of RT-PCR with APC and/or BCT diagnostic methods should be advocated for detection of S. stercoralis infection.

Alcoholic patients are more susceptible to Strongyloides stercoralis infection. The chronic use of alcohol raises the levels of endogenous corticosteroids, which regulates the development of larvae and stimulates the differentiation of rhabditiform into infective filariform larvae, thus inducing internal autoinfection. Therefore, early diagnosis is important to prevent severe strongyloidiasis. The aim of this study was to evaluate the efficacy of parasitological methods, according to the parasite load and the number of stool samples, for diagnosis of S. stercoralis infection, as well the peripheral blood eosinophil count in alcoholic patients. A total of 330 patients were included in this study. The diagnosis was established using three parasitological methods: agar plate culture, Baermann-Moraes method and spontaneous sedimentation. Peripheral eosinophilia was considered when the level was >600 eosinophils/mm3. The agar plate culture (APC) had the highest sensitivity (97.3%). However, the analysis of multiple samples increased the sensitivity of all parasitological methods. The sensitivities of the methods were influenced by the parasite load. When the larval number was above 10, the sensitivity of APC was 100%, while in spontaneous sedimentation the sensitivity reached 100% when the larval number was above 50. In the present study, 15.4% of alcoholic patients infected with S. stercoralis (12/78) had increased peripheral blood eosinophil count (above 600 eosinophils/mm3). For an efficient parasitological diagnosis of S. stercoralis infection in alcoholic patients, repeated examination by two parasitological methods must be recommended, including agar plate culture due to its higher sensitivity. Moreover, S. stercoralis infection was associated with eosinophilia, mostly in patients excreting up to 10 larvae/g faeces.

Strongyloides stercoralis infection in immunocompromised subjects, including chronic alcoholics, can lead to a severe disease. Moreover, its prevalence in alcoholic patients seems to be higher than that in the general population. The aims of this study were to evaluate the frequency of S. stercoralis infection in alcoholic patients and to investigate the influence of alcohol intake on the parasite load, as well as to evaluate the sensitivity of three different parasitological methods according to the larval output. Fecal samples of 1290 chronic alcoholic patients were examined by spontaneous sedimentation, Baermann–Moraes, and agar plate culture (APC) methods. S. stercoralis was the most frequent parasite found (14.5%; n = 187). Alcoholic individuals infected with Strongyloides stercoralis had a higher daily consumption of alcohol than those who were not infected, 528.6 and 403.0 g/day, respectively (p < 0.05). In addition, individuals with higher alcohol intake presented an increase in parasite load. The S. stercoralis diagnostic method with the highest sensitivity was APC, 97.9% (183/187). In conclusion, S. stercoralis seems to be the most frequent parasite found in alcoholic individuals from endemic areas and alcohol intake is positively associated with S. stercoralis larvae output. In addition, this study confirms that APC is the most sensitive parasitological method used for Strongyloides diagnosis.

Improved agar plate culture conditions for diagnosis of Strongyloides stercoralis

The infection burden of Strongyloides stercoralis in India remains poorly defined. We aimed to estimate the burden of S. stercoralis infection among immunocompromised patients at our tertiary care hospital in north India and evaluated the performance of multiple diagnostic tests. Paired stool and blood samples were collected from 498 immunosuppressed individuals. Screening included stool microscopy without concentration, Baermann's funnel method, Agar plate and Harada Mori cultures, 18S ribosomal RNA gene real-time polymerase chain reaction (RT-PCR), and anti-Strongyloides IgG antibody ELISA. Bayesian latent class analysis (BLCA) was performed to estimate diagnostic accuracy without assuming a gold standard. Overall, 16.9% (n = 84/498) of immunosuppressed individuals were positive by a composite reference standard, most commonly detected by a combination of ELISA and RT-PCR. Among single tests, BLCA estimated ELISA sensitivity of 74.5% (95% credible interval [CrI]: 62.7-84.5) and specificity of 88.3% (95% CrI: 85.4-90.9). Culture and RT-PCR showed sensitivities of 62.9% (95% CrI: 50.0-75.1) and 62.6% (95% CrI: 50.2-74.6) and specificities of 99.8% (95% CrI: 99.4-100.0) and 95.5% (95% CrI: 93.6-97.2), respectively. ELISA plus RT-PCR demonstrated the best performance with 87.5% (95% CrI: 76.9-95.0) sensitivity and 89.0% (95% CrI: 83.4-94.7) specificity. Strongyloides stercoralis infection was most frequent among patients with hypereosinophilia syndromes (33.3%), and increasing absolute eosinophilia count independently predicted infection. This study highlights a high burden of S. stercoralis infection in immunocompromised patients in north India and underscores the utility of combining serological and molecular assays for optimal detection in high-risk populations.

Epidemiology and clinical aspects of Strongyloides stercoralis infection in Cambodia

BackgroundStrongyloides stercoralis is a parasite that causes strongyloidiasis in humans. It is prevalent in the tropics and sub-tropics where poor sanitation is a common problem. The true prevalence of S. stercoralis in Ethiopia is underestimated due to the lack of a “Gold” standard diagnostic method. Moreover, its prevalence across altitudinal gradient in Amhara Region has not been studied.MethodsA cross-sectional study was conducted among 844 schoolchildren in Amhara Region from April to December 2019. A stool sample was collected from each study participant and processed using formol ether concentration technique (FECT), spontaneous tube sedimentation technique (STST), Baermann concentration technique (BCT), agar plate culture (APC) and real-time polymerase chain reaction (RT-PCR). Data were entered using EpiData and analyzed by SPSS version 23 statistical software. Prevalence of S. stercoralis infection was determined using a single diagnostic technique and combination of techniques. Association of clinical variables with S. stercoralis infection was assessed by logistic regression and independent variables with p<0.05 were considered statistically significant.ResultsPrevalence of soil-transmitted helminths (STHs) and S. mansoni infections was 38.0% and 20.4%, respectively. Among STHs, the prevalence of hookworm infection was 32.8%. Prevalence of S. stercoralis infection was 39.0%, 28.8%, 10.9%, 10.3%, 4.0% and 2.0% by the respective, combinations of the five methods, RT-PCR, APC, BCT, STST and FECT. The highest prevalence rates, 48.2%, 45.0% and 41.1% of S. stercoralis were recorded in the age group of 12–14 years, males and rural dwellers, respectively. Prevalence rates of S. stercoralis infection in highland, semi-highland and lowland areas were 40.4%, 41.8% and 25.9%, respectively. Having abdominal pain (AOR = 2.48; 95% CI:1.65–3.72), cough (AOR = 1.63;95%CI:1.09–2.42), urticaria (AOR = 2.49;95%CI:1.50–4.01) and being malnourished (AOR = 1.44;95%:1.10–2.01) were significantly associated with strongyloidiasis.ConclusionPrevalence of S. stercoralis infection was high and varied across different altitudes in Amhara Region. Some clinical syndromes were found to be significantly associated with S. stercoralis infection. Therefore, proper diagnosis and preventive strategies against S. stercoralis infection are highly recommended to be devised and implemented in Amhara Region.

BackgroundTwo important helminths, Strongyloides stercoralis (an intestinal roundworm) and Opisthorchis viverrini (a liver fluke), are endemic in northeast Thailand. There have been national campaigns in place aimed at the control and eradication of soil-transmitted helminthiasis and opisthorchiasis in Thailand for several decades. However, these helminths still exist and raise concerns regarding public health. This study aimed to evaluate the current prevalence of S. stercoralis and O. viverrini infections in rural communities in northeast Thailand. The data from this study will be useful to improve strategies for future helminth prevention and control.MethodsA cross-sectional study was conducted from December 2016 to June 2017 in Mueang Khon Kaen district in Khon Kaen, Thailand. The participants were selected using a simple random sampling method. Demographic data were collected using a questionnaire. Stool samples were collected and processed using agar plate culture to determine the presence of S. stercoralis infection and an in-house formalin-ethyl acetate concentration technique to determine the presence of O. viverrini and other intestinal parasite infections (IPIs).ResultsIn total, 602 persons were enrolled. However, only 526 were analyzed for S. stercoralis and 387 for O. viverrini risk factors. The overall prevalence of S. stercoralis infection was 23.0% (95% confidence interval [95%CI]: 19.4 to 26.6). The prevalence of O. viverrini infection and IPIs other than S. stercoralis was 20.4% (95%CI: 16.5 to 24.8). The prevalence of O. viverrini infection was 19.4% (95%CI: 15.6 to 23.7). Male sex was significantly associated with S. stercoralis infection [Adjusted Odds Ratio (aOR) 4.0; 95%CI: 2.5 to 6.2; P-value < 0.001]. Males were significantly more likely to be infected with O. viverrini and other IPIs (aOR 4.1; 95%CI: 2.3 to 7.2, P-value < 0.001).ConclusionsThis study demonstrated that the updated prevalence of intestinal parasite infections is still high in rural communities in northeast Thailand, especially that of strongyloidiasis and opisthorchiasis.

OBJECTIVESThe objective of this study was to evaluate the prevalence of Strongyloides stercoralis and other intestinal parasites in patients receiving immunosuppressive drugs in northern Iran and to investigate related risk factors.METHODSThis cross-sectional study was conducted among 494 patients receiving immunosuppressive drugs, including cancer patients undergoing chemotherapy (n=188) and those treated with prolonged corticosteroid administration (n=306). All fresh fecal samples were examined using the direct wet-mount, formalin ethyl acetate concentration, and agar plate culture techniques.RESULTSIn total, 16.8% of patients were positive for at least 1 intestinal parasite; the helminthic and protozoan infection rates were 5.1% and 12.3%, respectively. The infection rate was significantly higher in corticosteroid-treated individuals (19.6%) than cancer patients (12.2%) (p<0.05). The prevalence rate of S. stercoralis among patients receiving chemotherapy and those treated with corticosteroids were 4.3% and 5.2%, respectively. The prevalence rate of S. stercoralis infection was significantly higher in older patients (p<0.05).CONCLUSIONSStrongyloidiasis is one of the most common parasites among patients receiving immunosuppressive drugs in northern Iran. Early diagnosis and proper treatment of these patients are necessary to minimize the complications of severe strongyloidiasis.

Background:Intestinal parasitic infections (IPIs) are among the most important etiologies of gastrointestinal disorders in developing countries. The present study was performed to determine the prevalence of IPIs in rural inhabitants of Fouman, northern Iran.Methods:Overall, 31 villages were randomly selected during 2015–2016. Stool samples were collected from 1500 inhabitants aged 2–87. The samples were examined by direct wet smear, formalin ethyl-acetate concentration and agar plate culture. Trichrome staining and modified acid-fast staining were used as confirmatory tests for intestinal amoeba and flagellates and cryptosporidium spp., respectively. Data were analyzed with Chi-Square and Fisher exact tests using SPSS.Results:8.06% of participants were positive for at least one intestinal parasite. The prevalence of mixed parasitic infections was 0.87%. The most prevalent IPIs were caused by Trichostrongylus spp. (3.13%), followed by Strongyloides stercoralis (1.5%), Giardia lamblia (1.3%), and Entamoeba coli (1.0%), Blastocystis hominis (0.86%), E. histolytica/dispar (0.53%), Endolimax nana (0.26%), Iodamoeba butschlii (0.13%), Trichuris trichiura (0.07%), Enterobius vermicularis (0.07%), Hook worm (0.07%) and E. hartmani (0.07%). Statistically, the prevalence of IPIs showed significant differences regarding the age groups, education status, occupation (P<0.001), and the habit of eating raw vegetables (P<0.007), whereas, the differences were insignificant with regard to sex (P=0.924) and water supply (P=0.088).Conclusion:The prevalence of IPIs, especially soil-transmitted helminthes (STHs) has sharply decreased in northern Iran. Excluding Trichostrongylus spp. and S. stercoralis, other intestinal parasites only produce a marginal and unnoticeable health problem in this area, today.

Strongyloides stercoralis is a neglected soil-transmitted helminth endemic in tropical and subtropical regions. This study aimed to determine the prevalence, risk factors, and spatial distribution of S. stercoralis infection in rural villages of Khon Kaen Province, Northeastern Thailand. A cross-sectional survey was conducted among 260 participants from 201 households across five randomly selected villages. Stool samples were analysed using agar plate culture and formalin-ethyl acetate concentration techniques, and soil samples were assessed for S. stercoralis DNA by PCR and physicochemical properties including pH, porosity, bulk density, moisture, organic matter, and nitrate. The prevalence of S. stercoralis infection was 16.15%, with agar plate culture detecting 41 cases (15.77%) compared to 12 cases (4.62%) by formalin-ethyl acetate concentration techniques. The highest prevalence was observed in Norng Thungmon village (31.80%). Risk factors included male gender, older age, being a head of household, living in homes with earthen floors, walking barefoot, and proximity to water sources. Soil samples from 169 households revealed an S. stercoralis detection rate of 8.3% via PCR. Positive soil samples were predominantly from Norng Huachang and Don Du villages. Spatial analysis identified significant clustering of infections within high-risk areas. Soil physicochemical properties, including pH, moisture, and organic matter, were measured, though no significant correlations were found with infection rates. In conclusion, S. stercoralis remains a significant health concern but is neglected in rural Khon Kaen, with identifiable human and environmental risk factors. Enhanced health education, improved sanitation, and targeted interventions are essential for reducing transmission in endemic areas.

Background and Aim: Diagnosis of intestinal parasites is confirmed by the recovery of protozoan trophozoites and cysts, helminthes eggs, and larvae in stool samples in the clinical parasitological laboratory. In this study, we look at the prevalence of intestinal parasitic infections (IPIs) in outpatient department and hospitalized patients from different age groups in Tripoli Central Hospital obtained from 2007 to 2009. Materials and Methods: We have used the traditional microscopic technique to diagnose IPIs in all received stool samples during the study period. Results: In total, 18,000 stool samples were examined and it was found that 15.7% of them had at least one parasite. The overall prevalence of intestinal protozoan parasites was as follows: Entamoeba histolytica/Entamoeba dispar 5.1%, Entamoeba coli 10%, Giardia lamblia 8.1%, and Cryptosporidium parvum 1%, while the prevalence of intestinal helminthic parasites in this study was as follows: Enterobius vermicularis 5%, Ascaris lumbricoides 0.5%, and Strongyloides stercoralis 0.01%. Other species of intestinal helminthes are not widely prevalent in Libya. We have found a high prevalence of intestinal parasites, especially the intestinal protozoan parasites. The nonpathogenic protozoan, E. coli, had the highest prevalence rate (10.0%). Conclusion: We conducted the stool sample testing by routine ova and parasite methods, and a concentration technique increases the validity of the estimates.

Intestinal parasitic infections such as strongyloidosis are more common among individuals with immune deficiency and sometimes accompanied by severe symptoms. The purpose of this cross-sectional study was to evaluate the prevalence of intestinal parasites with focus on strongyloidosis in hospitalized patients. A total number of 566 faecal samples were obtained from different wards and assessed by the use of direct smear, formalin-ether concentration, and agar plate culture procedures in order to find parasitic protozoa and helminthes. The findings revealed that 10.1% (n=57) of the examined samples were positive for intestinal parasites. The highest prevalence rate was related to Entamoeba coli (4.6%, n=26) and the lowest one was related to Strongyloides stercoralis (0.5%, n=3). In addition, Giardia lamblia prevalence rate was 3.2% (n=18) and the prevalence rate of Blastocystis hominis was 1.8% (n=10). The sensitivity of S. stercoralis diagnosis was equal for agar plate culture and formalin-ether concentration methods. This study demonstrated the significance of focus on intestinal parasites in hospitalized patients and highlighted the necessity of improving the insight in health care providers about the occurrence of parasitic infections especially strongyloidiasis in these patients.

Strongyloidiasis is a neglected tropical disease caused mainly by Strongyloides stercoralis, a nematode that can persist for decades in the human host with a very low parasitic burden and without specific symptoms. Hence, it is difficult to diagnose and control. Larval concentration and culture methods with fecal samples show higher sensitivity for the diagnosis of Strongyloides-infected individuals; however, these techniques are not routinely used, primarily due to the challenges associated with processing a substantial volume of fecal samples. In the current study, we comparatively evaluated the sensitivity and applicability of modifications made to the Rugai parasitological method for the diagnosis of strongyloidiasis in fecal samples of experimentally infected rats and in 68 individuals from an urban community close to Maceió, Brazil. The presence and quantity of parasite larvae in the feces were comparatively evaluated using different parasitological techniques. In the experimental model, we demonstrated that the modified Rugai technique (RMOD) allowed for significantly higher recovery of larvae than the original Rugai technique (RO). Moreover, the sediment was cleaner and easier to evaluate using optical microscopy. Compared to other parasitological techniques, such as agar-plate culture (A-PC) and spontaneous sedimentation (SS), the RMOD technique showed higher sensitivity in the detection of larvae in all infected groups and presented comparatively better performance, especially in rats with a low parasite burden. In the human population, among the 68 stool samples evaluated, Strongyloides larvae were detected in the feces of six individuals with an estimated prevalence of 8.82%. However, the performance of each parasitological method was remarkably different. SS identified Strongyloides larvae in only two individuals and A-PC in three, whereas RMOD was able to identify six infected individuals, resulting in sensitivities of 33.3%, 50%, and 100%, respectively. In conclusion, the modifications introduced to the Rugai technique resulted in improved sensitivity for the detection of Strongyloides spp. infections, especially in stool samples with a low parasite burden, in comparison with other routinely used parasitological techniques.

Association between Strongyloides stercoralis infection and cortisol secretion in alcoholic patients