Explore the vast range of titles available.

The majority of the 30–100 million people infected with Strongyloides stercoralis, a soil transmitted intestinal nematode, have subclinical (or asymptomatic) infections. These infections are commonly chronic and longstanding because of the autoinfective process associated with its unique life cycle. A change in immune status can increase parasite numbers, leading to hyperinfection syndrome, dissemination, and death if unrecognized. Corticosteroid use and HTLV-1 infection are most commonly associated with the hyperinfection syndrome. Strongyloides adult parasites reside in the small intestine and induce immune responses both local and systemic that remain poorly characterized. Definitive diagnosis of S. stercoralis infection is based on stool examinations for larvae, but newer diagnostics – including new immunoassays and molecular tests – will assume primacy in the next few years. Although good treatment options exist for infection and control of this infection might be possible, S. stercoralis remains largely neglected.

Strongyloides stercoralis, an intestinal parasitic nematode, infects more than 100 million people worldwide. Strongyloides are unique in their ability to exist as a free-living and autoinfective cycle. Strongyloidiasis can occur without any symptoms or as a potentially fatal hyperinfection or disseminated infection. The most common risk factors for these complications are immunosuppression caused by corticosteroids and infection with human T-lymphotropic virus or human immunodeficiency virus. Even though the diagnosis of strongyloidiasis is improved by advanced instrumentation techniques in isolated and complicated cases of hyperinfection or dissemination, efficient guidelines for screening the population in epidemiological surveys are lacking. In this review, we have discussed various conventional methods for the diagnosis and management of this disease, with an emphasis on recently developed molecular and serological methods that could be implemented to establish guidelines for precise diagnosis of infection in patients and screening in epidemiological surveys. A comprehensive analysis of various cases reported worldwide from different endemic and nonendemic foci of the disease for the last 40 years was evaluated in an effort to delineate the global prevalence of this disease. We also updated the current knowledge of the various clinical spectrum of this parasitic disease, with an emphasis on newer molecular diagnostic methods, treatment, and management of cases in immunosuppressed patients. Strongyloidiasis is considered a neglected tropical disease and is probably an underdiagnosed parasitic disease due to its low parasitic load and uncertain clinical symptoms. Increased infectivity rates in many developed countries and nonendemic regions nearing those in the most prevalent endemic regions of this parasite and the increasing transmission potential to immigrants, travelers, and immunosuppressed populations are indications for initiating an integrated approach towards prompt diagnosis and control of this parasitic disease.

Background Strongyloidiasis is commonly a clinically unapparent, chronic infection, but immuno suppressed subjects can develop fatal disease. We carried out a review of literature on hyperinfection syndrome (HS) and disseminated strongyloidiasis (DS), in order to describe the most challenging aspects of severe strongyloidiasis. Methods We conducted a structured search using PubMed to collect case reports and short case series on HS/DS published from 1991 to 2011. We restricted search to papers in English, Spanish, Italian and French. Case reports were classified as HS/DS according to given definitions. Results Records screened were 821, and 311 were excluded through titles and abstract evaluation. Of 510 full-text articles assessed for eligibility, 213 were included in qualitative analysis. As some of them were short case series, eventually the number of cases analyzed was 244. Steroids represented the main trigger predisposing to HS and DS (67% cases): they were mostly administered to treat underlying conditions (e.g. lymphomas, rheumatic diseases). However, sometimes steroids were empirically prescribed to treat signs and symptoms caused by unsuspected/unrecognized strongyloidiasis. Diagnosis was obtained by microscopy examination in 100% cases, while serology was done in a few cases (6.5%). Only in 3/29 cases of solid organ/bone marrow transplantation there is mention of pre-transplant serological screening. Therapeutic regimens were different in terms of drugs selection and combination, administration route and duration. Similar fatality rate was observed between patients with DS (68.5%) and HS (60%). Conclusions Proper screening (which must include serology) is mandatory in high - risk patients, for instance candidates to immunosuppressive medications, currently or previously living in endemic countries. In some cases, presumptive treatment might be justified. Ivermectin is the gold standard for treatment, although the optimal dosage is not clearly defined in case of HS/DS.

Strongyloidiasis is a much-neglected soil born helminthiasis caused by the nematode Strongyloides stercoralis. Human derived S. stercoralis can be maintained in dogs in the laboratory and this parasite has been reported to also occur in dogs in the wild. Some authors have considered strongyloidiasis a zoonotic disease while others have argued that the two hosts carry host specialized populations of S. stercoralis and that dogs play a minor role, if any, as a reservoir for zoonotic S. stercoralis infections of humans. We isolated S. stercoralis from humans and their dogs in rural villages in northern Cambodia, a region with a high incidence of strongyloidiasis, and compared the worms derived from these two host species using nuclear and mitochondrial DNA sequence polymorphisms. We found that in dogs there exist two populations of S. stercoralis, which are clearly separated from each other genetically based on the nuclear 18S rDNA, the mitochondrial cox1 locus and whole genome sequence. One population, to which the majority of the worms belong, appears to be restricted to dogs. The other population is indistinguishable from the population of S. stercoralis isolated from humans. Consistent with earlier studies, we found multiple sequence variants of the hypervariable region I of the 18 S rDNA in S. stercoralis from humans. However, comparison of mitochondrial sequences and whole genome analysis suggest that these different 18S variants do not represent multiple genetically isolated subpopulations among the worms isolated from humans. We also investigated the mode of reproduction of the free-living generations of laboratory and wild isolates of S. stercoralis. Contrary to earlier literature on S. stercoralis but similar to other species of Strongyloides, we found clear evidence of sexual reproduction. Overall, our results show that dogs carry two populations, possibly different species of Strongyloides. One population appears to be dog specific but the other one is shared with humans. This argues for the strong potential of dogs as reservoirs for zoonotic transmission of S. stercoralis to humans and suggests that in order to reduce the exposure of humans to infective S. stercoralis larvae, dogs should be treated for the infection along with their owners.

Strongyloidiasis is a soil-transmitted helminthiasis that is estimated to affect 300–600 million people across Asia, Africa, South and central America, and the Pacific. This neglected parasitic disease is most known for its ability to persist as a lifelong infection due to autoinfection and its risk of hyperinfection and disseminated disease during immunosuppression, which has a more than 60% case fatality. Despite the large global burden of strongyloidiasis, there have been no large-scale public health programmes or WHO guidelines directed towards its control and elimination. However, over the past decade, key scientific and policy changes along with requests from endemic countries have led to WHO incorporating strongyloidiasis into its 2021–30 roadmap and public health targets for control and elimination of neglected tropical diseases. In 2024, WHO published its first guideline on public health control of strongyloidiasis with a single recommendation: in endemic settings with a Strongyloides stercoralis infection prevalence of 5% or higher (measured either with Baermann or agar plate culture from stool specimens), WHO conditionally recommends mass drug administration with single-dose ivermectin (200 μg/kg; oral therapy) in all age groups from 5 years and older to reduce strongyloidiasis. This Review, written by the 2023–24 strongyloidiasis guidelines development group along with WHO colleagues and international experts, presents a summary of the recently published WHO guideline recommendation for strongyloidiasis, and the supporting evidence, considerations for public health implementation, and future research needs.

Detection of Strogyloides -specific IgG antibodies in urine and serum has been used in diagnostic and epidemiological studies on strongyloidiasis. However, the usefulness of these assays in assessing responses to anthelmintic treatment is unclear. Thus, we evaluated the diagnostic performance and temporal profiles of Strongyloides -specific IgG antibodies in a cohort of participants at baseline and post-treatment. The participants were prospectively screened for baseline parasitic infections by fecal examination [agar plate culture technique (APCT) and formalin-ethyl acetate concentration technique (FECT)] and digital droplet polymerase reaction (ddPCR) for Strongyloides stercoralis . At each sampling point, Strongyloides -specific IgG in urine and serum were measured by an in-house S . ratti -based enzyme-linked immunosorbent assay (ELISA). At baseline, 169 of 351 participants (48.1%) had S . stercoralis infection by the combined fecal examination and ddPCR. The diagnostic sensitivities of IgG in urine and serum were 91.1% and 88.2%, respectively. The participants were given treatment with a single oral dose of ivermectin (IVM, 200 μg/kg) and were followed up by fecal and immunological diagnosis at 3 to 18 months post-treatment. The cure rate of IVM treatment evaluated by APCT and ddPCR was 88.3% at three months post-treatment. The profiles of IgG in urine in the curative treatment group showed a significant trend of decline with time post-treatment (Kruskal-Wallis test = 113.4–212.6, p value < 0.0001) and the lowest levels were seen 12 months post-treatment. The treatment response (> 50% reduction in urinary IgG antibody units) was 100%, and conversion from positive to negative results was 65.4%. The treatment response and conversion to negative assessed by serum IgG-ELISA were similar to those by urine IgG-ELISA. The results from this long-term diagnostic study highlight the utility of urinary IgG and serum IgG for screening and monitoring treatment outcomes in strongyloidiasis.

The human-infecting parasite Strongyloides fuelleborni subspecies kellyi has been reported from the island of New Guinea. We analyzed fecal DNA extracts (n = 164) from 19 infants in Papua New Guinea by using Strongyloides real-time PCR and undertook metabarcoding of cox1 and 18S rRNA hypervariable regions I and IV loci. Eight infants were infected with Strongyloides spp.; 7 were infected with S. fuelleborni subsp. fuelleborni and 1 with a Strongyloides sp. previously misattributed to S. fuelleborni subsp. kellyi. Phylogenetic and haplotyping analyses indicated S. fuelleborni in Papua New Guinea belongs to the Indochina subclade of S. fuelleborni subsp. fuelleborni and is not a unique subspecies. We report molecular evidence of S. fuelleborni subsp. fuelleborni infection in humans in the Pacific. Our findings also demonstrate the potential co-existence of an undescribed human-infecting Strongyloides sp. on the island of New Guinea, indicating a need for renewed clinical and epidemiologic investigations into infant strongyloidiasis.

Strongyloides stercoralis (Ss) is a parasitic infection affecting 50–100 million people globally, with significant immune and metabolic consequences, particularly in immunocompromised individuals. While Strongyloides infection is known to modulate the host immune system, the role of angiopoietin-like proteins (AGPTLs), which regulate inflammation and immune responses, has not been explored in this context. In this study, we investigated the systemic levels of AGPTL-2, -3, -4, -6, and -8 in 60 Ss-infected ( Ss +) and 56 uninfected ( Ss -) individuals. AGPTL levels were quantified using enzyme-linked immunosorbent assays (ELISA). We also assessed the effect of anthelmintic treatment on AGPTL levels in Ss + individuals. Our results show that Ss+ individuals had significantly elevated levels of AGPTL-2, -3, -6, and -8 compared to Ss- individuals. After anthelmintic treatment, these elevated levels were significantly reduced. Principal component analysis (PCA) revealed distinct clustering of AGPTLs between Ss + and Ss - groups, explaining 25.1% and 36.1% of the variance, respectively. Additionally, a positive correlation between AGPTL levels and IgG suggested an association with immune activation. These findings suggest that Strongyloides infection is associated with elevated AGPTL levels, which decrease following effective treatment. This highlights the potential role of AGPTLs as biomarkers for diagnosing and monitoring infection and treatment response. Further research is needed to better understand the mechanisms of AGPTL regulation in parasitic infections and their impact on immune modulation and metabolic alterations.

Strongyloidiasis is endemic in many remote Indigenous communities in Australia. Early diagnosis, treatment, and follow-up of chronic strongyloidiasis can prevent life-threatening clinical complications and decrease transmission in these endemic communities. The aim of this paper is to evaluate the effectiveness and sustainability of a primary healthcare strategy designed to measure and reduce the prevalence of strongyloidiasis in four remote communities in northeast Arnhem Land. The primary healthcare strategy was a prospective, longitudinal, health-systems intervention designed to integrate serological testing for chronic strongyloidiasis into the Indigenous preventive adult health assessment utilising the electronic health-record systems in four Aboriginal health services. Positive cases were recalled for treatment, and opportunistic follow-up serology after six months. Results were tracked using Strongyloides reports generated by the electronic health-record system. This paper describes the changes in prevalence, effectiveness of treatment, and reinfection during the implementation phase, 2012-2016. An improved Strongyloides electronic report was developed to evaluate the effectiveness and sustainability of the intervention to the end of 2020. During the entire period 2012-2020, 84% (2390/2843) of the resident adults in the four communities were tested for strongyloidiasis at least once. Prevalence was reduced from 44% (1056/2390) ever-positive to 10% (232/2390) positive on their last test. Of positive, treated cases with a follow-up serology test, the last test was negative in 85% (824/967) of individuals. Point prevalence continued to decrease in each community four years after the end of the implementation phase. The results provided practice-based evidence of a significant decrease in the prevalence of strongyloidiasis attributable to the strategy which could be replicated in other health services utilising electronic health-record systems. The final evaluation demonstrated the sustainability and ongoing benefits for endemically infected communities, and the key role that health services can play in strongyloidiasis prevention and control programs.