Correction: Association of Strongyloides stercoralis infection and type 2 diabetes mellitus in northeastern Thailand: Impact on diabetic complication-related renal biochemical parameters.

[This corrects the article DOI: 10.1371/journal.pone.0269080.].

High Efficacy of Ivermectin for Strongyloidiasis Treatment.

Infection with Strongyloides stercoralis is often asymptomatic but can be life-threatening in immunocompromised patients, which can be prevented by ivermectin (IVM) treatment. The efficacy of IVM has been reported to have lessened over time in some regions as a consequence of prolonged use and mass treatment campaigns. Ivermectin has been used in Thailand for more than a decade; therefore, we investigated the efficacy of a single dose (200 µg/kg) of IVM against in asymptomatic strongyloidiasis in northeastern Thailand. Fecal samples were collected before and 2 weeks after treatment and were analyzed for the presence of Strongyloides using a modified agar plate culture and the formalin-ethyl acetate concentration technique. Our results showed that single-dose IVM treatment successfully eliminated S. stercoralis infection in asymptomatic individuals in the endemic area with a 100% cure rate, indicating the high efficacy of IVM treatment in strongyloidiasis in northeast Thailand.

Molecular identification and genetic diversity of zoonotic hookworm infections in domestic dogs from northeastern, Thailand.

Hookworm infections remain a significant public health concern in tropical and subtropical regions, including Thailand. This study investigated the species and genetic diversity of hookworm infections in domestic dogs from northeastern Thailand. The molecular analysis focused on amplifying and sequencing specific regions of ribosomal RNA genes (ITS1-5.8S-ITS2 region) and the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene in hookworm larvae recovered from 21 domestic dog stool samples. Among 21 larvae (one larva per infected dog) analyzed, 14 had sequences identical to Ancylostoma caninum, and 7 showed sequences almost identical to Ancylostoma ceylanicum. Phylogenetic analysis of cox1 sequences placed A. caninum and A. ceylanicum in separate clades. The median-joining network of A. caninum cox1 sequences from Thailand showed high haplotype diversity and belonged to the same cluster as sequences from Australia while forming separate clusters from those of A. caninum samples from the USA. The available published A. ceylanicum cox1 sequences (n = 33), in combination with seven sequences in the present study, represented 15 haplotypes distributed among three clusters. Interestingly, A. ceylanicum sequences from dogs and humans shared the same haplotypes. These findings are crucial for recognizing the potential for zoonotic transmission, highlighting the necessity for targeted control measures, and increasing awareness among pet owners and healthcare professionals to mitigate the risk of hookworm transmission to humans.

Strongyloides stercoralis infection reduces Fusicatenibacter and Anaerostipes in the gut and increases bacterial amino-acid metabolism in early-stage chronic kidney disease.

Understanding gut bacterial composition and proteome changes in patients with early-stage chronic kidney disease (CKD) could lead to better methods of controlling the disease progression. Here, we investigated the gut microbiome and microbial functions in patients with S. stercoralis infection (strongyloidiasis) and early-stage CKD. Thirty-five patients with early stages (1-3) of CKD were placed in two groups matched for population characteristics and biochemical parameters, 12 patients with strongyloidiasis in one group and 23 uninfected patients in the other. From every individual, a sample of their feces was obtained and processed for 16S rRNA sequencing and metaproteomic analysis using tandem liquid chromatography-mass spectrometry (LC-MS/MS). Strongyloides stercoralis infection per se did not significantly alter gut microbial diversity. However, certain genera (Bacteroides, Faecalibacterium, Fusicatenibacter, Sarcina, and Anaerostipes) were significantly more abundant in infection-free CKD patients than in infected individuals. The genera Peptoclostridium and Catenibacterium were enriched in infected patients. Among the significantly altered genera, Fusicatenibacter and Anaerostipes were the most correlated with renal parameters. The relative abundance of members of the genus Fusicatenibacter was moderately positively correlated with estimated glomerular filtration rate (eGFR) (r = 0.335, p = 0.049) and negatively with serum creatinine (r = -0.35, p = 0.039). Anaerostipes, on the other hand, showed a near-significant positive correlation with eGFR (r = 0.296, p = 0.084). Individuals with S. stercoralis infection had higher levels of bacterial proteins involved in amino-acid metabolism. Analysis using STITCH predicted that bacterial amino-acid metabolism may also be involved in the production of colon-derived uremic toxin (indole), a toxic substance known to promote CKD. Strongyloides stercoralis infection is, therefore, associated with reduced abundance of Fusicatenibacter and Anaerostipes (two genera possibly beneficial for kidney function) and with increased bacterial amino-acid metabolism in the early-stages of CKD, potentially producing uremic toxin. This study provides useful information for prevention of progression of CKD beyond the early stages.

Comparative efficacy of chemical and botanical pediculicides in Thailand and 4% dimeticone against head louse, Pediculus humanus capitis.

Head louse infestations remain a global public-health concern due to increased resistance of lice to artificial pediculicides. In Thailand, there is a lack of comparative data on the current efficacy of pediculicides for treating head lice. In this study, we explored the status of botanical and toxic synthetic pediculicides with that of 4% dimeticone liquid gel for treating head lice in Thailand. The ex-vivo pediculicidal activity of various pediculicidal shampoos available at drugstores in Thailand was assessed and compared with that of 4% dimeticone liquid gel. The shampoos chosen were based on active ingredients toxic to lice (1% permethrin, 0.6% carbaryl, 0.15% Stemona root crude extract, or mixed plant extracts), whereas dimeticone acts physically on lice. We found that exposure to 4% dimeticone liquid gel following the manufacturer's instructions completely killed 100% of head lice in 15 min, whereas other pediculicide products failed to kill the great majority of head lice, whether treatment was for 10 min (resulting in 0% to 50.0% mortality) or 30 min (resulting in 17.0% to 60.0% mortality). We also extended a clinical assessment to confirm the efficacy of 1% permethrin for treating head lice in infested schoolchildren. In this clinical assessment, none of the 26 children treated with 1% permethrin shampoo achieved a cure after two applications. These results highlight that 4% dimeticone demonstrated a higher ex-vivo pediculicidal efficacy compared to both chemical and botanical pediculicides in Thailand. Conversely, 1% permethrin showed low efficacy in both laboratory and clinical assessments. Given its physical mode of action, 4% dimeticone merits consideration as an alternative treatment option for lice in Thailand, particularly in cases where treatment with toxic pediculicides has proven ineffective.

Chronic Strongyloides stercoralis infection increases presence of the Ruminococcus torques group in the gut and alters the microbial proteome.

We explored the impact of chronic Strongyloides stercoralis infection on the gut microbiome and microbial activity in a longitudinal study. At baseline (time-point T0), 42 fecal samples from matched individuals (21 positive for strongyloidiasis and 21 negative) were subjected to microbiome 16S-rRNA sequencing. Those positive at T0 (untreated then because of COVID19 lockdowns) were retested one year later (T1). Persistent infection in these individuals indicated chronic strongyloidiasis: they were treated with ivermectin and retested four months later (T2). Fecal samples at T1 and T2 were subjected to 16S-rRNA sequencing and LC-MS/MS to determine microbial diversity and proteomes. No significant alteration of indices of gut microbial diversity was found in chronic strongyloidiasis. However, the Ruminococcus torques group was highly over-represented in chronic infection. Metaproteome data revealed enrichment of Ruminococcus torques mucin-degrader enzymes in infection, possibly influencing the ability of the host to expel parasites. Metaproteomics indicated an increase in carbohydrate metabolism and Bacteroidaceae accounted for this change in chronic infection. STITCH interaction networks explored highly expressed microbial proteins before treatment and short-chain fatty acids involved in the synthesis of acetate. In conclusion, our data indicate that chronic S. stercoralis infection increases Ruminococcus torques group and alters the microbial proteome.

Strongyloides stercoralis infection induces gut dysbiosis in chronic kidney disease patients.

BACKGROUND: Strongyloides stercoralis infection typically causes severe symptoms in immunocompromised patients. This infection can also alter the gut microbiota and is often found in areas where chronic kidney disease (CKD) is common. However, the relationship between S. stercoralis and the gut microbiome in chronic kidney disease (CKD) is not understood fully. Recent studies have shown that gut dysbiosis plays an important role in the progression of CKD. Hence, this study aims to investigate the association of S. stercoralis infection and gut microbiome in CKD patients. METHODOLOGY/PRINCIPAL FINDINGS: Among 838 volunteers from Khon Kaen Province, northeastern Thailand, 40 subjects with CKD were enrolled and divided into two groups (S. stercoralis-infected and -uninfected) matched for age, sex and biochemical parameters. Next-generation technology was used to amplify and sequence the V3-V4 region of the 16S rRNA gene to provide a profile of the gut microbiota. Results revealed that members of the S. stercoralis-infected group had lower gut microbial diversity than was seen in the uninfected group. Interestingly, there was significantly greater representation of some pathogenic bacteria in the S. stercoralis-infected CKD group, including Escherichia-Shigella (P = 0.013), Rothia (P = 0.013) and Aggregatibacter (P = 0.03). There was also a trend towards increased Actinomyces, Streptococcus and Haemophilus (P > 0.05) in this group. On the other hand, the S. stercoralis-infected CKD group had significantly lower representation of SCFA-producing bacteria such as Anaerostipes (P = 0.01), Coprococcus_1 (0.043) and a non-significant decrease of Akkermansia, Eubacterium rectale and Eubacterium hallii (P > 0.05) relative to the uninfected group. Interesting, the genera Escherichia-Shigella and Anaerostipes exhibited opposing trends, which were significantly related to sex, age, infection status and CKD stages. The genus Escherichia-Shigella was significantly more abundant in CKD patients over the age of 65 years and infected with S. stercoralis. A correlation analysis showed inverse moderate correlation between the abundance of the genus of Escherichia-Shigella and the level of estimated glomerular filtration rate (eGFR). CONCLUSIONS/SIGNIFICANCE: Conclusion, the results suggest that S. stercoralis infection induced gut dysbiosis in the CKD patients, which might be involved in CKD progression.

Curcumin-loaded nanocomplexes ameliorate the severity of nonalcoholic steatohepatitis in hamsters infected with Opisthorchis viverrini.

BACKGROUND: Comorbidity of Opisthorchis viverrini (OV) infection and nonalcoholic fatty-liver disease (NAFLD) enhances NAFLD progression to nonalcoholic steatohepatitis (NASH) by promoting severe liver inflammation and fibrosis. Here, we investigated the effect of supplementation with curcumin-loaded nanocomplexes (CNCs) on the severity of NASH in hamsters. METHODOLOGY: Hamsters were placed in experimental groups as follows: fed standard chow diet (normal control, NC); fed only high-fat and high-fructose (HFF) diet; O. viverrini-infected and fed HFF diet (HFFOV); group fed with blank nanocomplexes (HFFOV+BNCs); groups fed different doses of CNCs (25, 50 and 100 mg/kg body weight: HFFOV+CNCs25; HFFOV+CNCs50; HFFOV+CNCs100, respectively) and a group given native curcumin (HFFOV+CUR). All treatment were for three months. RESULTS: The HFF group revealed NAFLD as evidenced by hepatic fat accumulation, ballooning, mild inflammation and little or no fibrosis. These changes were more obvious in the HFFOV group, indicating development of NASH. In contrast, in the HFFOV+CNCs50 group, histopathological features indicated that hepatic fat accumulation, cell ballooning, cell inflammation and fibrosis were lower than in other treatment groups. Relevantly, the expression of lipid-uptake genes, including fatty-acid uptake (cluster of differentiation 36), was reduced, which was associated with the lowering of alanine aminotransferase, total cholesterol and triglyceride (TG) levels. Reduced expression of an inflammation marker (high-mobility group box protein 1) and a fibrosis marker (alpha smooth-muscle actin) were also observed in the HFFOV+CNCs50 group. CONCLUSION: CNCs treatment attenuates the severity of NASH by decreasing hepatic steatosis, inflammation, and fibrosis as well as TG synthesis. CNCs mitigate the severity of NASH in this preclinical study, which indicates promise for future use in patients.

Investigation of gut microbiota and short-chain fatty acids in Strongyloides stercoralis-infected patients in a rural community.

Intestinal parasitic infections can change gut microbiota and short-chain fatty acids (SCFAs). We aimed to study the interaction among Strongyloides stercoralis, human gut microbiota, and serum SCFAs in a community. Fifty-two subjects in Donchang sub-district, Khon Kaen Province, northeastern Thailand, were included based on specific inclusion and exclusion criteria. Characteristics of the participants were matched between those positive for S. stercoralis infection alone (no other intestinal parasites; Ss+, n=26) and uninfected controls (infection status confirmed by polymerase chain reaction (PCR); Ss-, n=26). Serum short-chain fatty acids were evaluated by gas chromatography-mass spectrometry. DNA was extracted from individual faecal samples and then pooled into two groups (Ss+ and Ss-) for amplification and sequencing of the V3-V4 region of the 16S gene with next-generation technology. We explored the impact of infection with S. stercoralis on the faecal microbiota: individuals infected with this parasite exhibited increased alpha diversity of bacteria. At the genus level, gut microbiota in Ss+ patients showed high abundances of Escherichia-Shigella and Bacteroides but low abundances of the genera Bifidobacterium, Lactobacillus, and Blautia. PCR of individual samples to identify certain species of interest gave results consistent with those from next-generation sequencing of pooled samples and showed that significantly more Ss+ samples contained Bacteroides fragilis. Intriguingly, a major SCFA, acetic acid, was significantly decreased in S. stercoralis infection. In conclusion, S. stercoralis infection caused an imbalance of gut microbiota and decreased acetic acid in serum. This information adds to the knowledge concerning the effect of intestinal nematode-related chronic diseases.

Association of Strongyloides stercoralis infection and type 2 diabetes mellitus in northeastern Thailand: Impact on diabetic complication-related renal biochemical parameters.

BACKGROUND: Several studies have demonstrated that helminth infections provide a degree of protection against Type 2 diabetes mellitus (T2DM). However, the relationship between Strongyloides stercoralis infection and T2DM has scarcely been investigated and the protective effect of infection against development of diabetic complications is unclear. In this study, we aimed to investigate the relationship between S. stercoralis infection and T2DM in a rural area of Khon Kaen Province, Thailand. The impact of S. stercoralis infection on diabetic complication-related kidney function biochemical parameters and body-mass index (BMI) was also assessed. METHODOLOGY: Using a cross-sectional study design, S. stercoralis infection and T2DM assessments were conducted between October 2020 and May 2021. Associations between S. stercoralis infection, T2DM, and socioeconomic factors were analyzed using multivariable logistic regression analyses. Diabetic complication-related biochemical parameters relating largely to kidney function (estimated glomerular filtration rate (eGFR), urine albumin-to-creatinine ratio (UACR), serum creatinine, uric acid, alanine transaminase (ALT), and low-density lipoprotein cholesterol (LDL-C)) and BMI of participants with and without T2DM were compared between groups with or without S. stercoralis infection. RESULTS: One hundred and seven out of 704 individuals (15.20%) were positive for S. stercoralis, and 283 people were diagnosed with T2DM. Of those with T2DM, 11.31% (32/283) were infected with S. stercoralis and of those without T2DM, 17.82% (75/421) were infected with S. stercoralis. Multivariate analysis revealed that T2DM was inversely correlated with S. stercoralis infection (Adjusted OR = 0.49; 95% CI: 0.30, 0.78; p = 0.003), while male, increasing age, lower education level, and alcohol intake were positively associated with infection. Those infected with S. stercoralis had lower eGFR levels and higher ALT and UACR levels than those in the uninfected group. CONCLUSION: This finding indicates that S. stercoralis infection was inversely associated with T2DM in northeastern Thailand, but participants infected with S. stercoralis had lower eGFR levels and higher ALT and UACR levels. Infection with S. stercoralis might lead to worse complication-related renal biochemical parameters.

Repeated Ivermectin Treatment Induces Ivermectin Resistance in Strongyloides ratti by Upregulating the Expression of ATP-Binding Cassette Transporter Genes.

Ivermectin (IVM) is a widely used anthelmintic. However, with widespread use comes the risk of the emergence of IVM resistance, particularly in strongyloidiasis. Adenosine triphosphate (ATP)-binding cassette (ABC) transporter genes play an important role in the IVM-resistance mechanism. Here, we aimed to establish an animal experimental model of IVM resistance by frequent treatment of Strongyloides ratti with subtherapeutic doses of IVM, resistance being evaluated by the expression levels of ABC transporter genes. Rats infected with S. ratti were placed in experimental groups as follows: 1) untreated control (control); 2) treated with the mutagen ethyl methanesulfonate (EMS); 3) injected with 100 µg/kg body weight of IVM (IVM); 4) treated with a combination of EMS and IVM (IVM+EMS). Parasites were evaluated after four generations. Extent of IVM resistance was assessed using IVM sensitivity, larval development, and expression of ABC genes. By the F4 generation, S. ratti in the IVM group exhibited significantly higher levels of IVM resistance than did other groups according to in vitro drug-sensitivity tests and inhibition of larval development (IC50 = 36.60 ng/mL; 95% CI: 31.6, 42.01). Expression levels of ABC isoform genes (ABCA, ABCF, and ABCG) were statistically significantly higher in the IVM-resistant line compared with the susceptible line. In conclusion, IVM subtherapeutic doses induced IVM resistance in S. ratti by the F4 generation with corresponding upregulation of some ABC isoform genes. The study provides a model for inducing and assessing drug resistance in Strongyloides.

Opisthorchis viverrini Infection Induces Metabolic and Fecal Microbial Disturbances in Association with Liver and Kidney Pathologies in Hamsters.

Opisthorchis viverrini (Ov) infection causes hepatobiliary diseases and is a major risk factor for cholangiocarcinoma. While several omics approaches have been employed to understand the pathogenesis of opisthorchiasis, effects of Ov infection on the host systemic metabolism and fecal microbiota have not been fully explored. Here, we used a 1H NMR spectroscopy-based metabolic phenotyping approach to investigate Ov infection-induced metabolic disturbances at both the acute (1 month postinfection, 1 mpi) and chronic (4 mpi) stages in hamsters. A total of 22, 3, and 4 metabolites were found to be significantly different in the liver, serum, and urine, respectively, between Ov+ and Ov- groups. Elevated levels of hepatic amino acids and tricarboxylic acid (TCA)-cycle intermediates (fumarate and malate) were co-observed with liver injury in acute infection, whereas fibrosis-associated metabolites (e.g., glycine and glutamate) increased at the chronic infection stage. Lower levels of lipid signals ((CH2)n and CH2CH2CO) and higher levels of lysine and scyllo-inositol were observed in serum from Ov+ hamsters at 1 mpi compared to Ov- controls. Urinary levels of phenylacetylglycine (a host-bacterial cometabolite) and tauro-ß-muricholic acid were higher in the Ov+ group, which coexisted with hepatic and mild kidney fibrosis. Furthermore, Ov+ animals showed higher relative abundances of fecal Methanobrevibacter (Archaea), Akkermansia, and Burkholderia-Paraburkholderia compared to the noninfected controls. In conclusion, along with liver and kidney pathologies, O. viverrini infection resulted in hepatic and mild renal pathologies, disturbed hepatic amino acid metabolism and the TCA cycle, and induced changes in the fecal microbial composition and urinary host-microbial cometabolism. This study provides the initial step toward an understanding of local and systemic metabolic responses of the host to O. viverrini infection.

Phylogeography and demographic history of Thai Pediculus humanus capitis (Phthiraptera: Pediculidae) revealed by mitochondrial DNA sequences.

Pediculus humanus (human louse) is a hematophagous insect that feeds on human blood. It is distributed worldwide. Understanding phylogeography and population-genetic structure of the human louse will illuminate the evolution of this insect and the dynamics of how resistance alleles might spread in the landscape. In this work, we used mitochondrial (cox1 and cytb genes) sequences of the human louse to investigate genetic diversity, population-genetic structure and demographic history of the louse in Thailand. Human lice in Thailand belonged to mitochondrial clades A and C. Most genetic variation was attributed to intra-region 65.71% within provinces for clade A and 68.92% for clade C, while inter-region level was 34.40% among provinces within regions for clade A and 20.09% for clade C. Neutrality and other indices suggested that louse populations from clades A and C in Thailand have experienced a population expansion. But head lice from Khon Kaen Province in clade C demonstrated a significant recent population bottleneck or natural selective pressure with constant population size. Head lice in Thailand showed varying degrees of low to high genetic differentiation at the level of province with many populations being genetically distinct from each other among regions and within the same region. Knowledge of the clades present in Thailand and that gene flow occurs between regions will assist in developing appropriate strategies for management of head lice at the local level in the country.

An optimized agar plate culture improves diagnostic efficiency for Strongyloides stercoralis infection in an endemic community.

We aimed to compare the efficacy of modified agar plate fecal culture (mAPC) and standard agar plate culture (sAPC) for diagnosis of Strongyloides stercoralis infection in a community at Khon Kaen Province, Thailand. Fecal samples were collected from participants individually (n = 1076) and were tested using these two methods. Modified APC and sAPC detected 129 (11.99%) and 91 (8.46%) infected individuals, respectively. Thirty-eight participants were negative according to sAPC, but positive for mAPC. Moreover, in the participants who were positive for both methods, the number of worm developmental stages obtained was higher for mAPC than for sAPC. Our study suggests that mAPC is an effective and useful tool for S. stercoralis diagnosis and can be applied for mass-screening in community and/or control programs.

Improved agar plate culture conditions for diagnosis of Strongyloides stercoralis.

Strongyloides stercoralis infection causes gastrointestinal symptoms and can lead to severe disease in immunocompromised hosts. Live larvae are passed in feces, encouraging the common use of diagnosis by cultivation methods including agar plate culture (APC), the gold-standard technique. Nevertheless, APC has limitations, especially since there can be considerable day-to-day fluctuations in numbers of larvae produced. Herein, we collected stool samples from heavily infected subjects with strongyloidiasis in Khon Kaen Province, Thailand, to evaluate modifications (temperature, pH, nutrition source and salinity) to APC conditions to maximize the number of S. stercoralis worms counted. Best results were obtained using a modified APC with the following conditions: pH 6.0, 0.5% of NaCl, addition of yeast extract for nutrition and incubation at 29-30 °C. This modified APC was more sensitive for detection of S. stercoralis than was standard APC or the formalin-ethyl acetate concentration technique. In brief, this finding suggests that a modification of standard APC conditions increases the counts of S. stercoralis.

Effect of a health education program on reduction of pediculosis in school girls at Amphoe Muang, Khon Kaen Province, Thailand.

BACKGROUND: Pediculosis caused by head lice (Pediculus humanus capitis) infestation is still an important health problem in schoolchildren, especially girls, worldwide, including in Thailand. Although pediculicidal agents effectively kill head lice, the re-infestation rate is still high. Thus, prevention is an important strategy for any sustainable control program. We aimed to develop and evaluate the efficacy of a health education program for increasing knowledge, changing attitudes and promoting preventive practices to reduce prevalence of pediculosis among school girls in Amphoe Muang, Khon Kaen, northeastern Thailand. METHODOLOGY: Six schools were selected using multistage simple randomization and were allocated into intervention or control groups. A total of 267 girls was enrolled from these schools. A "knowledge, attitude and practice" (KAP) questionnaire, consent forms and health education materials were constructed and tested by experts and in one pilot school before the main investigation. Baseline prevalence of adult lice and nits was determined. The health education package was given only to the intervention group. The KAP questionnaire was re-evaluated at two months after intervention. RESULTS: At baseline, the prevalence and intensity of head lice infestation, and the KAP scores did not differ significantly between the two groups. After re-evaluation at two months, the KAP score was significantly greater in the intervention group. A significant decrease of the infestation rate from 59% to 44% was observed in the intervention group, whereas infestation increased in the control group (from 56% to 65%). The incidence of new cases in the intervention group (6.14%) was lower than in the control group (12.62%). CONCLUSION: These findings indicated that the newly-established health education package is an effective tool for increasing KAP and reducing head lice infestation in school girls. Efforts to combat pediculosis in schoolchildren elsewhere may consider including this, or a similar, health education package in their programs.