BACKGROUND: The Gran Chaco ecoregion is a well-known hotspot of several neglected tropical diseases (NTDs) including Chagas disease, soil-transmitted helminthiasis and multiparasitic infections. Interspecific interactions between parasite species can modify host susceptibility, pathogenesis and transmissibility through immunomodulation. Our objective was to test the association between human co-infection with intestinal parasites and host parasitaemia, infectiousness to the vector and immunological profiles in Trypanosoma cruzi-seropositive individuals residing in an endemic region of the Argentine Chaco.
METHODS: We conducted a cross-sectional serological survey for T. cruzi infection along with an intestinal parasite survey in two adjacent rural villages. Each participant was tested for T. cruzi and Strongyloides stercoralis infection by serodiagnosis, and by coprological tests for intestinal parasite detection. Trypanosoma cruzi bloodstream parasite load was determined by quantitative PCR (qPCR), host infectiousness by artificial xenodiagnosis and serum human cytokine levels by flow cytometry.
RESULTS: The seroprevalence for T. cruzi was 16.1% and for S. stercoralis 11.5% (n = 87). We found 25.3% of patients with Enterobius vermicularis. The most frequent protozoan parasites were Blastocystis spp. (39.1%), Giardia lamblia (6.9%) and Cryptosporidium spp. (3.4%). Multiparasitism occurred in 36.8% of the examined patients. Co-infection ranged from 6.9% to 8.1% for T. cruzi-seropositive humans simultaneously infected with at least one protozoan or helminth species, respectively. The relative odds of being positive by qPCR or xenodiagnosis (i.e. infectious) of 28 T. cruzi-seropositive patients was eight times higher in people co-infected with at least one helminth species than in patients with no such co-infection. Trypanosoma cruzi parasite load and host infectiousness were positively associated with helminth co-infection in a multiple regression analysis. Interferon-gamma (IFN-γ) response, measured in relation to interleukin (IL)-4 among humans infected with T. cruzi only, was 1.5-fold higher than for T. cruzi-seropositive patients co-infected with helminths. The median concentration of IL-4 was significantly higher in T. cruzi-seropositive patients with a positive qPCR test than in qPCR-negative patients.
CONCLUSIONS: Our results show a high level of multiparasitism and suggest that co-infection with intestinal helminths increased T. cruzi parasitaemia and upregulated the Th2-type response in the study patients.

BACKGROUND: Hypereosinophilic syndrome can produce cardiac involvement and endomyocardial fibrosis, which have a poor prognosis. However, there is limited information regarding cardiac involvement among migrants from Latin America with eosinophilia related to helminthiasis.
METHODS: We conducted a pilot observational study where an echocardiography was performed on migrants from Latin America with both eosinophilia (>450 cells/μL) and a diagnosis of helminth infection, and on migrants from Latin America without eosinophilia or helminth infection. Microbiological techniques included a stool microscopic examination using the Ritchie\'s formalin-ether technique, and a specific serology to detect Strongyloides stercoralis antibodies.
RESULTS: 37 participants were included, 20 with eosinophilia and 17 without eosinophilia. Twenty (54.1%) were men with a mean age of 41.3 (SD 14.3) years. Helminthic infections diagnosed in the group with eosinophilia were: 17 cases of S. stercoralis infection, 1 case of hookworm infection, and 2 cases of S. stercoralis and hookworm coinfection. Among participants with eosinophilia, echocardiographic findings revealed a greater right ventricle thickness (p = 0.001) and left atrial area and volume index (p = 0.003 and p = 0.004, respectively), while showing a lower left atrial strain (p = 0.006) and E-wave deceleration time (p = 0.008). An increase was shown in both posterior and anterior mitral leaflet thickness (p = 0.0014 and p = 0.004, respectively) when compared with participants without eosinophilia.
CONCLUSIONS: Migrants from Latin America with eosinophilia related to helminthic infections might present incipient echocardiographic alterations suggestive of early diastolic dysfunction, that could be related to eosinophilia-induced changes in the endomyocardium.

BACKGROUND: Estimation of prevalence of Strongyloides stercoralis infection is required in endemic areas, in order to identify areas in need of control programmes. Data on prevalence of strongyloidiasis in Madagascar are scant. Aim of this work was to estimate prevalence of S. stercoralis in four districts of Madagascar.
METHODS: Fecal and serum samples collected in the context of a previous study on schistosomiasis were tested with S. stercoralis real-time PCR and serology, respectively. A multiplex real-time PCR for Ascaris lumbricoides, Ancylostoma duodenalis, Necator americanus, and Trichuris trichiura was done on fecal samples collected in the areas demonstrating higher prevalence of strongyloidiasis. Comparisons between proportions were made using Fisher exact test, with false discovery rate correction used for post-hoc comparisons. A multivariable Firth logistic regression model was used to assess potential risk factors for S. stercoralis infection.
RESULTS: Overall, 1775 serum samples were tested, of which 102 of 487 (20.9%) and 104 of 296 (35.2%) were serological-positive in Marovoay and in Vatomandry districts (both coastal areas), respectively, compared to 28 of 496 (5.6%) and 30 of 496 (6.1%) in Tsiroanomandidy and in Ambositra districts (both highlands), respectively (adj. p < 0.001). PCR for S. stercoralis was positive in 15 of 210 (7.1%) and in 11 of 296 (3.7%) samples from Marovoay from Vatomandry, respectively, while was negative for all samples tested in the other two districts. High prevalence of A. lumbricoides (45.9%), hookworm (44.6%) and T. trichiura (32.1%) was found in Vatomandry. In the multivariable analysis, strongyloidiasis was associated with hookworm infection. Hookworm infection was also associated with male sex and lower education level.
CONCLUSIONS: S. stercoralis prevalence proved higher in coastal areas compared to highlands. Different climatic conditions may explain this distribution, along with previous rounds of anthelminthics distributed in the country, which may have reduced the parasite load in the population. The high prevalence of the other soil-transmitted helminths (STH) in Vatomandry was unexpected, given the good coverage with benzimidazole in control campaigns. Further studies are needed to explore the risk factors for STH and S. stercoralis infections in Madagascar, in order to align with the WHO recommendations.

Wells\' syndrome is a rare inflammatory skin disease characterized by pruritic erythematous lesions and cutaneous edema, often accompanied by eosinophilia. Parasitic infestations, such as toxocariasis and strongyloidiasis, can serve as triggers. However, Wells\' syndrome associated with toxocariasis and strongyloidiasis has not been reported previously in Indonesia. Herein, we present a case of a 27-year-old male with a chief complaint of recurrent, pruritic, and painful erythematous rash on the right lower leg for 6 months, accompanied by fever and diarrhea. Physical examination showed cutaneous edema with erythematous macules and bullae on the affected leg. Peripheral blood eosinophilia was noted, and the histopathological analysis demonstrated flame figures, confirming the diagnosis of Wells\' syndrome. A stool culture identified Strongyloides stercoralis, confirming strongyloidiasis, and serological testing was positive for toxocariasis immunoglobulin G antibodies. The patient was treated with albendazole 400 mg twice daily for 3 weeks resulted in clinical improvement observed by the 14th day. The diverse clinical features of Wells\' syndrome present a challenge to clinicians in making an accurate diagnosis, which typically hinges on histopathological assessment and identifying flame figures. Therefore, clinicopathological correlation is important to establish an accurate diagnosis.

UNASSIGNED: Syndrome of inappropriate anti-diuretic hormone secretion (SIADH) is associated with strongyloidiasis. Herein, a rare case of severe SIADH secondary to disseminated strongyloidiasis in a kidney transplant recipient is reported.
UNASSIGNED: A case involving a 43-year-old male kidney transplant recipient with severe disseminated Strongyloides stercoralis infection is reported. The patient was a construction worker with a history of consuming undercooked yellow eel and sashimi. On admission, the patient presented with poor appetite, nausea, vomiting and diarrhea. Laboratory investigations revealed persistent significant hyponatremia and low serum osmolality, confirming the diagnosis of SIADH. S. stercoralis was detected in the stool and bronchoalveolar lavage fluid. He was treated with empirical albendazole because S. stercoralis was detected in the stool; however, his symptoms and hyponatremia did not improve until ivermectin was administered, after which SIADH resolved quickly.
UNASSIGNED: This case suggests that S. stercoralis infection should be included in the differential diagnosis when a kidney transplant recipient presents with gastrointestinal symptoms and SIADH. In such situations, pre- or post-transplant screening for S. stercoralis is needed, and early ivermectin treatment is very important.

The potential cross-transmission of Strongyloides stercoralis between dogs and humans has become an increasing focus of strongyloidiasis research and control programs. However, the role of cats and wild felids in the maintenance and transmission cycles of human and canine strongyloidiasis has received sparse attention. Feline strongyloidiasis epidemiology remain enigmatic. We conducted a systematic review and meta-analysis to assess the global prevalence of Strongyloides spp. in felines and reviewed cross-species infection studies to elucidate the transmission cycle of some feline Strongyloides species. Literature searched from seven databases identified 42 eligible prevalence studies published between 1985 and 2024. Of these, 44 datasets from 40 studies were included in the meta-analysis. Using a random effect model combined with the Rogan-Gladen method, we estimated the pooled global prevalence of Strongyloides spp. in felines at 13.3% (95% CI: 8.3-18.3%), with rates of 12.2% (95% CI: 6.7-17.8%) in domestic cats (Felis catus) and 20.0% (95% CI: 14.9-25.2%) in wild felids. Feline strongyloidiasis was distributed across all six WHO regions, with Africa (49.7%; 95% CI: 40.0-59.3%) and the Western Pacific (46.9%; 95% CI: 42.6-51.1%) showing the highest pooled prevalence. Subgroup analysis revealed a significantly higher prevalence of Strongyloides infection in stray domestic cats (29.2%; 95% CI: 6.3-52.1%) compared to pet cats (9.3%; 95% CI: 3.7-14.9) and shelter cats (4.4; 95% CI: 0-9.0). Historical cross-species transmission studies demonstrated variable susceptibility of cats to human- or canine-derived S. stercoralis. It remains inconclusive whether cats act as a reservoir for S. stercoralis infection in humans or vice versa. Feline strongyloidiasis is a prevalent condition in wild, stray, pet and shelter cats. Much of the available prevalence data does not discriminate to species level, and the role of cross-species transmission in feline S. stercoralis infections remains obscure. Future studies would benefit from utilising molecular genotyping tools to enable species-level phylogenetic differentiation.

BACKGROUND: The sensitivity of parasitological and molecular methods is unsatisfactory for the diagnosis of strongyloidiasis, and serological techniques are remaining as the most effective diagnostic approach. The present study aimed to design and produce a chimeric recombinant antigen from Strongyloides stercoralis immunoreactive antigen (SsIR) and Ss1a antigens, using immune-informatics approaches, and evaluated its diagnostic performance in an ELISA system for the diagnosis of human strongyloidiasis.
RESULTS: The coding sequences for SsIR and Ss1a were selected from GenBank and were gene-optimized. Using bioinformatics analysis, the regions with the highest antigenicity that did not overlap with other parasite antigens were selected. The chimeric recombinant antigen SsIR- Ss1a, was constructed. The solubility and physicochemical properties of the designed construct were analyzed and its tertiary structures were built and evaluated. The construct was expressed into the pET-23a (+) expression vector and the optimized DNA sequences of SsIR-Ss1a (873 bp) were cloned into competent E. coli DH5α cells. Diagnostic performances of the produced recombinant antigen, along with a commercial kit were evaluated in an indirect ELISA system, using a panel of sera from strongyloidiasis patients and controls. The physicochemical and bioinformatics evaluations revealed that the designed chimeric construct is soluble, has a molecular with of 35 KDa, and is antigenic. Western blotting confirmed the immunoreactivity of the produced chimeric recombinant antigen with the sera of strongyloidiasis patients. The sensitivity and specificity of the indirect ELISA system, using the produced SsIR-Ss1a chimeric antigen, were found to be 93.94% (95% CI, 0.803 to 0.989) and 97.22% (95% CI, 0.921 to 0.992) respectively.
CONCLUSIONS: The preliminary findings of this study suggest that the produced SsIR-Ss1a chimeric antigen shows promise in the diagnosis of human strongyloidiasis. However, these results are based on a limited panel of samples, and further research with a larger sample size is necessary to confirm its accuracy. The construct has potential as an antigen in the ELISA system for the serological diagnosis of this neglected parasitic infection, but additional validation is required.

BACKGROUND: Strongyloidiasis is caused by a neglected nematode, manifesting as chronic intestinal infection with potentially severe manifestations. The disease is an emerging problem in non-endemic countries affecting travelers and migrants. Diagnosis of strongyloidiasis is hampered by the lack of standardization and absence of a gold standard. Since adequate direct methods to detect the motile larvae in stool samples are not widely available, other techniques such as serology have been developed.
METHODS: We evaluated three commercial ELISA kits (DRG Instruments, IVD Research, and Bordier Affinity Products) to detect IgG antibodies against Strongyloides stercoralis assays utilizing serum samples from travelers with microscopically confirmed strongyloidiasis (n = 50) and other imported helminthic infections (n = 159) as well as healthy controls (n = 50).
RESULTS: The DRG, IVD, and Bordier assays showed sensitivities of 58.0%, 64.0%, and 56.0%, respectively. Specificity values were 96.0%, 96.0%, and 92.0% in healthy controls, and 67.3%, 62.9%, and 76.7% in cases with other helminth infections, respectively. Cross-reactions were mostly observed in cases with other nematodes (37.5%, 42.5%, and 20.0%, respectively), but also in trematode (33.3%, 38.1%, and 19.0%, respectively) and in cestode infections (25.0%, 30.0%, and 32.5%, respectively).
CONCLUSIONS: The study demonstrates the diagnostic limitations of serological assays to detect or exclude cases of strongyloidiasis in returning travelers, who frequently present with recent or acute infections.

The skin-penetrating gastrointestinal parasitic nematode Strongyloides stercoralis causes strongyloidiasis, which is a neglected tropical disease that is associated with severe chronic illness and fatalities. Unlike other human-infective nematodes, S. stercoralis cycles through a single free-living generation and thus serves as a genetically tractable model organism for understanding the mechanisms that enable parasitism. Techniques such as CRISPR/Cas9-mediated mutagenesis and transgenesis are now routinely performed in S. stercoralis by introducing exogenous DNA into free-living adults and then screening their F1 progeny for transgenic or mutant larvae. However, transgenesis in S. stercoralis has been severely hindered by the inability to establish stable transgenic lines that can be propagated for multiple generations through a host; to date, studies of transgenic S. stercoralis have been limited to heterogeneous populations of transgenic F1 larvae. Here, we develop an efficient pipeline for the generation of stable transgenic lines in S. stercoralis. We also show that this approach can be used to efficiently generate stable transgenic lines in the rat-infective nematode Strongyloides ratti. The ability to generate stable transgenic lines circumvents the limitations of working with heterogeneous F1 populations, such as variable transgene expression and the inability to generate transgenics of all life stages. Our transgenesis approach will enable novel lines of inquiry into parasite biology, such as transgene-based comparisons between free-living and parasitic generations.

Strongyloidiasis is a chronic infection caused by the intestinal nematode parasite Strongyloides stercoralis and is characterized by a diverse spectrum of nonspecific clinical manifestations. This report describe a case of disseminated strongyloidiasis with urination difficulty, generalized weakness, and chronic alcoholism diagnosed through the presence of worms in the urinary sediment. A 53-year-old man was hospitalized for severe abdominal distension and urinary difficulties that started 7-10 days prior. The patient also presented with generalized weakness that had persisted for 3 years, passed loose stools without diarrhea, and complained of dyspnea. In the emergency room, approximately 7 L of urine was collected, in which several free-living female adult and rhabditiform larvae of S. stercoralis, identified through their morphological characteristics and size measurements, were detected via microscopic examination. Rhabditiform larvae of S. stercoralis were also found in the patient\'s stool. During hospitalization, the patient received treatment for strongyloidiasis, chronic alcoholism, peripheral neurosis, neurogenic bladder, and megaloblastic anemia, and was subsequently discharged with improved generalized conditions. Overall, this report presents a rare case of disseminated strongyloidiasis in which worms were detected in the urinary sediment of a patient with urination difficulties and generalized weakness combined with chronic alcoholism, neurogenic bladder, and megaloblastic anemia.