A silent threat behind bars: Serosurvey and associated risk factors for strongyloidiasis in female inmates and correctional officers.

Strongyloidiasis has been a neglected parasitic infection caused by Strongyloides genus parasites. Despite assessment of S. stercoralis exposure in different vulnerable populations, seroprevalence in inmates worldwide remains to be fully established. Due to poor sanitation and lack of personal hygienic practices, incarcerated individuals have been considered prone to spread infectious illnesses. Accordingly, the present study has assessed exposure and associated risk factors for strongyloidiasis in women inmates and correctional officers at the Women's State Penitentiary of Parana, part of the third largest incarceration complex in Brazil at the time. Blood samplings were performed in 2020 and 2021from a total of 503 women inmates and 92 correctional officers. Participants voluntarily responded to an epidemiological questionnaire to assess associated risk factors to strongyloidiasis. Serological analysis was performed by ELISA for anti-S. stercoralis IgG detection. Statistical analysis was performed using R software, adopting a 5% level of significance. The data were submitted to univariate analysis by chi-square or Fisher´s Exact test for assessing the association among seropositivity and the variables. The variables with p-value < 0.2 in the univariate analysis were considered fit to be included in the logistic regression. In overall, 356/503 (70.8%; 95% CI: 66.7-74.6) inmates were seropositive for anti-S. stercoralis antibodies, with no statistically associated risk factor to seropositivity. A total of 57/92 (62.0%; 95% CI: 51.8-71.2) correctional officers were seropositive, and logistic regression revealed that individuals older than 50 years were more likely seropositive. In conclusion, the high endemicity observed herein has indicated a history of previous exposure to S. stercoralis and warned for a systematic strongyloidiasis screening for inmates, to prevent long term morbidity and disseminated infection during incarceration.

Introduction to Strongyloides stercoralis Anatomy.

Strongyloides stercoralis, commonly known as the human threadworm, is a skin-penetrating gastrointestinal parasitic nematode that infects hundreds of millions of people worldwide. Like other Strongyloides species, S. stercoralis is capable of cycling through a single free-living generation. Although S. stercoralis and the free-living nematode Caenorhabditis elegans are evolutionarily distant, the free-living adults of S. stercoralis are similar enough in size and morphology to C. elegans adults that techniques for generating transgenics and knockouts in C. elegans have been successfully adapted for use in S. stercoralis. High-quality genomic and transcriptomic data are also available for S. stercoralis. Thus, one can use a burgeoning array of functional genomic tools in S. stercoralis to probe questions about parasitic nematode development, physiology, and behavior. Knowledge gained from S. stercoralis will inform studies of other parasitic nematodes such as hookworms that are not yet amenable to genetic manipulation. This review describes the basic anatomy of S. stercoralis.

High prevalence of anti-Strongyloides antibody in SARS-CoV-2-infected human sera in a Thai hospital: Rapid serological screening.

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can stimulate a systemic inflammatory response with severe lung involvement, multisystem dysfunction, and death in some cases. Immunosuppressive treatments have been proposed for management of COVID-19 patients, but these bring the risk of flare-up of pre-existing infections. Strongyloidiasis can become severe or fatal in immunocompromised individuals. This cross-sectional study determined the prevalence of anti-Strongyloides IgG antibody in sera collected from SARS-CoV-2 infected persons in a tertiary-care Thai hospital from January 2021 to January 2022. The survey was conducted using a rapid immunochromatographic test (ICT) kit based on a recombinant antigen of Strongyloides stercoralis known to be IgG-immunoreactive. High prevalence of anti-Strongyloides IgG antibody was found. Out of 297 SARS-CoV-2-infected patients 117 (39.4 %, 95 % CI 33.8-45.2 %) were positive for S. stercoralis according to the ICT kit. In areas where strongyloidiasis is endemic, we suggest using this point-of-care ICT kit for routine rapid screening in seriously ill COVID-19 patients who will be subjected to immunosuppressive treatment. Prompt anthelminthic treatment should be administered to prevent serious systemic strongyloidiasis in at-risk patients.

A case of disseminated strongyloidiasis diagnosed by worms in the urinary sediment.

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.

The generation of stable transgenic lines in the human-infective nematode Strongyloides stercoralis.

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.

Successful Prompt Diagnosis of Strongyloidiasis in an Outpatient Setting at Amami Oshima Island in Japan: A Case Report.

Strongyloidiasis is a parasitic infection caused by the nematode Strongyloides stercoralis that presents with a variety of nonspecific symptoms. Diagnosis is challenging unless physicians suspect this disease and perform sensitivity tests. We report a case of strongyloidiasis with protein-losing gastroenteropathy-like symptoms in a 92-year-old Japanese female with lower extremity edema and hypoalbuminemia. In this case, the patient refused invasive tests for a complete examination; however, an agar plate culture of a stool sample was used to diagnose strongyloidiasis. The patient was treated with ivermectin during the second visit. One month later, leg edema and hypoproteinemia improved. When the cause of the symptoms is unclear, physicians should be aware of the possibility of strongyloidiasis in a person residing in a tropical or subtropical environment, where human feces are used as fertilizer and individuals frequently go barefoot in agricultural settings.

High-throughput sequencing of Strongyloides stercoralis - a fatal disseminated infection in a dog.

The rhabditid nematode Strongyloides stercoralis is known worldwide as the causative agent of strongyloidiasis in humans. In addition to public health concerns, S. stercoralis also infects dogs, which represent a possible reservoir for potentially zoonotic transmissions. We describe the first confirmed case of fatal disseminated infection in a dog in the Czech Republic. The microscopic and histological results were supported by a complex genotyping approach. Using high-throughput sequencing of the hypervariable region (HVR-IV) of 18S rDNA and Sanger sequencing of the partial cytochrome c oxidase subunit 1 gene (cox1), the potentially zoonotic haplotype/lineage A of S. stercoralis was confirmed, while the solely canine haplotype/lineage B was not found. The development of the disease is mainly associated with immunodeficiency, and in this case, it was triggered by inappropriate treatment, in particular the use of corticosteroids.

Carbon dioxide shapes parasite-host interactions in a human-infective nematode.

Skin-penetrating nematodes infect nearly one billion people worldwide. The developmentally arrested infective larvae (iL3s) seek out hosts, invade hosts via skin penetration, and resume development inside the host in a process called activation. Activated infective larvae (iL3as) traverse the host body, ending up as parasitic adults in the small intestine. Skin-penetrating nematodes respond to many chemosensory cues, but how chemosensation contributes to host seeking, intra-host development, and intra-host navigation - three crucial steps of the parasite-host interaction - remains poorly understood. Here, we investigate the role of carbon dioxide (CO2) in promoting parasite-host interactions in the human-infective threadworm Strongyloides stercoralis. We show that S. stercoralis exhibits life-stage-specific preferences for CO2: iL3s are repelled, non-infective larvae and adults are neutral, and iL3as are attracted. CO2 repulsion in iL3s may prime them for host seeking by stimulating dispersal from host feces, while CO2 attraction in iL3as may direct worms toward high-CO2 areas of the body such as the lungs and intestine. We also identify sensory neurons that detect CO2; these neurons are depolarized by CO2 in iL3s and iL3as. In addition, we demonstrate that the receptor guanylate cyclase Ss-GCY-9 is expressed specifically in CO2-sensing neurons and is required for CO2-evoked behavior. Ss-GCY-9 also promotes activation, indicating that a single receptor can mediate both behavioral and physiological responses to CO2. Our results illuminate chemosensory mechanisms that shape the interaction between parasitic nematodes and their human hosts and may aid in the design of novel anthelmintics that target the CO2-sensing pathway.

Expression of Heat Shock Protein 70 (HSP70) and Astacin Genes of Strongyloides stercoralis as well as HSP70 and HSP17.1 Genes of S. ratti in Adult and Larval Stages of S. stercoralis.

Background: Uncovering the roles and characteristics of pathogenesis-related molecules can help us develop novel management methods in parasitology. In this study, we studied the expression levels of Strongyloides stercoralis heat shock protein70 (HSP70) (Sst-hsp-70) and astacin (Sst-ast) as pathogenesis-related genes as well as the expression of S. ratti HSP70 and HSP17.1 (Sra-hsp-70, Sra-hsp-17.1) in the larvae and adult stages of S. stercoralis. Methods: A hyperinfection isolate of S. stercoralis from Gilan Province, northern Iran was cultivated on nutrient agar. After a couple of days, parasites in different stages of life were collected, and total RNA was extracted. The expression levels of astacin and HSP genes were compared by real-time PCR. Results: Statistically higher expression levels of Sst-ast, Sst-hsp-70, and Sra-hsp-70 genes in L3 larvae than in adults were observed. However, the expression level of Sra-hsp-17.1 was non-significantly lower in the larval stage than in adult worms. Conclusion: Higher expression levels of Sst-ast, Sst-hsp-70, and Sra-hsp-70 genes in the larval stages of S. stercoralis suggest the potential role of these enzymes in parasite cutaneous invasion and pathogenesis. However, higher expression of Srahsp-17.1 in adult forms is probably involved in resistance and survival mechanisms. The similarity in gene expression between S. stercoralis and S. ratti can provide helpful hints to better understand strongyloidiasis from various perspectives, including pathogenesis, proper diagnosis, and targeted treatment.

Application of Nested-qPCR-High Resolution Melting (HRM) Technology on Strongyloides stercoralis Isolates from Iran.

PURPOSE: Strongyloides stercoralis is a parasite with special characteristics presenting it as a unique nematode. Iran is an endemic area for S. stercoralis. In this study, nested-qPCR-high resolution melting (HRM) technology was applied on some human isolates of S. stercoralis from this country by focusing on evolutionary genetics analysis. METHODS: Twelve human isolates of S. stercoralis were collected from four endemic provinces of Iran. Genomic DNA was extracted from a single filariform larva for every isolate. Using specific primers targeting partial regions in cox1 gene, nested-qPCR-HRM was performed and melting-curve profiles were analyzed alongside the evaluation of genetic proximity and phylogenetic analysis using MEGA7 and DnaSP5 software. RESULTS: The melting temperature (Tm) values of the isolates were 77.9 °C-78.3 °C. All isolates from Guilan, Mazandaran, and Khouzestan Provinces shared Tm values of 78.2 °C to 78.3 °C, while the isolates from Hormozgan Province showed Tm values of 77.9 °C, 78.0 °C, and 78.1 °C. The phylogenetic tree illustrated that the sequences of the current study included nine haplotypes. Tajima's D index analyses showed that cox1 gene in S. stercoralis isolates was negative (Tajima's D = - 0.27). CONCLUSION: The isolates were divided into five temperature groups. Although HRM assay compared to PCR sequencing identified more limited genetic changes, it revealed that the mean of Tm of the isolates from Hormozgan Province was lower than those of other provinces and represented specific haplotypes for this geographical region on the phylogenetic tree.

Clinical insights to address canine strongyloidosis in daily practice.

Canine strongyloidosis by Strongyloides stercoralis is a parasitic disease emerging in Europe, which represents both a veterinary clinical issue and a public health challenge because of the zoonotic potential. The disease, not yet frequent in Europe, could induce severe clinical signs in dogs; thus, an early diagnosis and appropriate treatment are desirable. The aim of the present work is to retrospectively investigate the clinical and paraclinical findings in sick dogs naturally infected by S. stercoralis, with particular attention to ultrasound (US) changes at the gastrointestinal level. Twelve dogs were included in the study. The diagnosis was made by means of larval morphological identification on faecal samples and PCR. Most dogs presented with gastrointestinal signs; diarrhea and weight loss were the most common presenting complaint. Only one dog showed respiratory signs, associated to a parasitic cutaneous nodule. Hypoproteinaemia, anaemia, leucocytosis and an increase in alpha2-globulin fraction at serum protein electrophoresis were common (>50%) but not constant findings. The most reported US picture was a fluid-filled, distended, atonic small intestine mostly associated with altered wall layering, while the wall thickness commonly associated with chronic enteritis was only rarely reported. These changes, associated with other clinical and paraclinical alterations, could increase the suspicion of canine strongyloidosis and may direct clinicians to include strongyloidosis in the differential diagnosis of dogs with diarrhea. The histological examination at the intestinal level, available in five dogs, revealed the presence of parasites from the full-thickness biopsy, but not from the endoscopic biopsy. The critical points of diagnosis in clinical practice are also discussed.

Epidemiological and clinical trends of imported strongyloidiasis in a referral international health unit, Barcelona, Spain: A 12-year period experience.

BACKGROUND: Imported strongyloidiasis in non-endemic countries has increasingly been diagnosed. The aim of the present study is to describe the main epidemiological and clinical characteristics of patients with imported strongyloidiasis attended in a referral International Health Unit and to detect trend changes over a 12-year period. METHODS: This is an observational retrospective study including all imported strongyloidiasis cases seen at the International Health Unit Vall d'Hebron-Drassanes (Barcelona, Spain) from January 2009 to December 2020. Epidemiological and clinical characteristics from included patients were collected. RESULTS: Overall, 865 cases of imported strongyloidiasis were diagnosed, of whom 472 (54.6 %) were men and mean age was 38.7 (SD 13.4) years. Most cases were diagnosed in migrants (830, 96 %). The distribution of the geographic origin was: Latin America (561, 67.6 %), Sub-Saharan Africa (148, 17.8 %), Asia (113, 13.6 %), North Africa (5, 0.6 %), Eastern Europe (2, 0.2 %), and North America (1, 0.1 %). The main reasons for consultation at the Unit were screening of health status (371, 42.9 %), laboratory test alteration (367, 42.4 %), gastrointestinal symptoms (56, 6.5 %), cutaneous symptoms (26, 3 %), and other clinical symptoms (45, 5.2 %). An increase in the number of cases was observed in the last years of the study period. CONCLUSIONS: Imported strongyloidiasis has increasingly been diagnosed in our referral unit, mostly due to screening strategies implementation. Most of the patients were young migrants coming from Latin America, with no symptoms at the time of diagnosis. The optimization of screening strategies will increase the detection and treatment of cases, reducing potential complications.

Massive Airway Bleeding Caused by Pulmonary Strongyloidiasis in a Patient with a Transplanted Kidney.

Introduction: We report a fatal case of massive airway bleeding caused by pulmonary strongyloidiasis in a patient with a transplanted kidney. Case Presentation: A 47-year-old male, regularly taking immunosuppressants post-kidney transplant, visited our hospital with symptoms of abdominal bloating, nausea, and emesis persisting for three days. After hospitalization, he developed a cough, hemoptysis, and respiratory failure. Sputum analysis confirmed an infestation with Strongyloides stercoralis. Despite receiving albendazole therapy and bronchoscopic management for bronchial hemorrhage, the patient ultimately died due to acute respiratory and circulatory collapse triggered by severe airway bleeding. Conclusion: Patients undergoing immunosuppressive therapy following kidney transplantation are at increased risk for disseminated strongyloidiasis. Consequently, infectious disease screening prior to transplantation, along with essential preventive pharmacotherapy, is of paramount importance.

Strongyloides stercoralis genotyping in a human population in southwestern Iran.

BACKGROUND: Strongyloidiasis is a neglected tropical disease (NTD) that is caused mainly by Strongyloides stercoralis, with an estimated 600 million people infected worldwide, and in fewer cases by Strongyloides fuelleborni fuelleborni and Strongyloides fuelleborni kellyi. A number of studies have been conducted on the genetic diversity of S. stercoralis in East and Southeast Asia; however, there is very limited corresponding information from West Asian countries, including Iran. METHODS: For Strongyloides worms collected from patients in southwestern Iran, the hypervariable regions I (HVR-I) and IV (HVR-IV) of the nuclear 18S ribosomal DNA (rDNA) locus (SSU) and a fragment of the subunit 1 mitochondrial cytochrome c oxidase gene (cox-1) were sequenced. For a subset of the worms, whole-genome sequencing data were generated. RESULTS: The cox-1 sequences of 136 worms isolated from 23 patients indicated that all isolates were S. stercoralis. Among the cox-1 sequences, 33 polymorphic sites and 13 haplotypes were found. The phylogenetic analysis demonstrated that some sequences clustered fairly closely with sequences from humans and dogs from other parts of the world, while others formed a separate, Iran-specific group. Among 64 S. stercoralis analyzed, we found three of the previously described SSU HVR-I haplotypes, with haplotype II being the most frequent haplotype. In contrast to Southeast Asia, where S. stercoralis heterozygous for different haplotypes at the HVR-I locus are rare, we found 20 worms to be heterozygous for two different HVR-I haplotypes, 18 of which fell into the Iran-specific cox-1 cluster. SSU-heterozygous worms also showed elevated heterozygosity at the whole-genome level. CONCLUSIONS: We conclude that the S. stercoralis population from the Khuzestan province shares much of the genetic diversity with the population in Southeast Asia, but there is an indication of additional genetic input. There appears to be some population structure with different subpopulations, which however do interbreed at least occasionally.

Identification and treatment of Strongyloides stercoralis infection in a Boston Terrier dog from south-eastern Australia.

Strongyloides stercoralis, the causative agent of strongyloidiasis, is a potentially zoonotic intestinal nematode endemic to northern Australia. Strongyloidiasis is typically observed in immunocompromised hosts and is characterised by gastrointestinal signs, respiratory symptoms and a failure to thrive. In immunocompromised hosts, hyperinfection syndrome and disseminated infections can prove life-threatening. A 24-month-old Boston Terrier dog was referred for investigation of chronic small and large intestinal watery hematochezic diarrhoea, emaciation and hematemesis. Small intestinal histology identified a nematode despite consecutive negative faecal flotations. A real-time polymerase chain reaction and Baermann test subsequently confirmed infection with S. stercoralis. The dog had received an oral parasiticide comprising milbemycin oxime and afoxolaner every month for the 11 months prior to this diagnosis. Despite fenbendazole being reported as successful in the treatment of canine strongyloidiasis, a course of fenbendazole failed to clear the infection. Eradication of S. stercoralis infection was confirmed after the administration of off-label ivermectin fortnightly for 12 doses. Attention should be paid to this nematode as the failure of routine copromicroscopic methods to diagnose S. stercoralis infections can result in misdiagnosis, mistreatment and progression of the disease. Off-label ivermectin may be an alternative to fenbendazole for the treatment of Strongyloides spp. infection in dogs.

Pulmonary strongyloidiasis and hyperinfection in a Patient with idiopathic inflammatory myopathy：A case report.

Pulmonary strongyloidiasis is a rare infection in patients with autoimmune diseases, and immunosuppression can lead to the development of hyperinfection syndrome with a high mortality rate. We present a case of a 78-year-old male with previous idiopathic inflammatory myopathy (IIM) with interstitial lung disease. He developed hyperinfection syndrome and respiratory failure, and diagnostic metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF) confirmed the presence of Strongyloides stercoralis. After treatment with ivermectin, the patient's symptoms improved. Therefore, adequate screening and prophylactic treatment are needed for people at risk of immunosuppression, which can reduce the occurrence of the devastating S. stercoralis hyperinfection syndrome. It also highlights mNGS as a highly accurate test for the detection of difficult to atypical pathogens.

A study implementing real-time PCR to identify Strongyloides species of third-stage larvae in human stool samples from Southern Vietnam.

Background: Strongyloidiasis, a neglected disease caused by intestinal nematodes of the genus, is endemic to tropical and subtropical areas such as Vietnam. Morphological methods only identify the genus, while DNA-molecular techniques are susceptible in Strongyloides spp. detection. The study aims to determine the prevalence of dominant Strongyloides species among the population in Duc Hoa district, Long An, Vietnam. Methods: A cross-sectional study used 1190 stool specimens collected from July 2017 to November 2018. All samples were transported within 2 h, stored at 2-8°C, and processed within 48 h for microscopy smear and culture at the Laboratory of Medical Parasitology, Pham Ngoc Thach University of Medicine (PNT). Then all positive samples with the above 2 methods were verified by real-time PCR technique. Real-time PCR amplification was conducted at the Laboratory of Molecular Biology, PNT. Results: Direct microscopy and modified Harada-Mori culture detected Strongyloides spp. larvae in 79/1190 samples (6.6%). About 94.2% of the DNA samples were Strongyloides stercoralis, 2.9% were co-infections with Strongyloides ratti and S. stercoralis, and 2.9% were patients with S. ratti. The identity of 12/14 sequences was confirmed as S. stercoralis with a high level of similarity (91.3%-100%) and over 98% for S. ratti. Conclusion: DNA-molecular techniques and sequence analysis are highly suitable for identifying Strongyloides species isolated from stool samples. It is remarkable evidence of the presence of zoonosis S. ratti disease in human, not just the known S. stercoralis. It is likely to result in a certain proportion of people being infected by this animal-borne infectious pathogen.

Frequency of strongyloidiasis and associated factors: Analysis of 13 years of laboratory results in a tertiary referral hospital in Honduras, 2010-2022

Introduction. The frequency of detected strongyloidiasis is affected by the selected laboratory method in the studied population. Considering that Honduras has few community-based studies, the analysis of the laboratory record data can provide information helping to understand this parasitosis. Objective. To estimate the frequency and to identify the factors associated with strongyloidiasis, analyzing the laboratory records of the Servicio de Parasitología at Hospital Escuela in Tegucigalpa (Honduras) between 2010 and 2022. Materials and methods. We carried out a descriptive, cross-sectional, analytical study. The laboratory diagnosis consisted of stool samples' examination by direct smear and modified Baermann technique. We estimated frequencies and percentages. The statistical association was calculated with prevalence ratios and a 95% confidence interval. Software R, version 4.2.0, and epiR package, version 2.0.46, were used to perform the analysis. Results. The frequency of strongyloidiasis was 0.29% (112/38,085). It was higher with the modified Baermann technique (0.87%; 40/4,575) among male patients (0.44%; 70/15,758). Regarding the age, strongyloidiasis was higher in the 20-40 years old group (0.41%; 28/6,886) with direct smear and 41-61 years old (1.14%; 14/1,232) group with the modified Baermann technique. Among the factors associated with strongyloidiasis were age between 20 and 61 years old (PR=2.26, CI 95%=1.53-3.31), male patients (PR=2.34, CI 95%=1.60-3.44), mucus (PR=1.86, CI 95%=1.22-2.83) and Charcot-Leyden crystals in stool (PR=8.47, CI 95%=5.14-13.96); watery stool (PR=2.39, CI 95%=1.55-3.68), and other helminthiases (PR=6.73, CI 95%=3.98-11.38). Associated factors to cases detected with the modified Baermann technique were outpatient consultation (PR=4.21, CI 95%=1.91-9.28) and formed stools (PR=3.99, CI95% =1.94-8.19). Conclusions. The modified Baermann technique increased the detection of strongyloidiasis almost four times. Most cases were distributed among male adults. The cases diagnosed exclusively with the modified Baermann technique have differences from those with observed larvae in the direct smear. It is necessary to develop community-based population studies.

Introducción. La detección de estrongiloidiasis depende del método de diagnóstico utilizado y la población estudiada. Dado que en Honduras hay pocos estudios poblacionales, el análisis de los datos de laboratorio puede generar información que ayude a entender esta parasitosis. Objetivo. Estimar la frecuencia e identificar los factores asociados a la estrongiloidiasis mediante el análisis de los registros de laboratorio del Servicio de Parasitología del Hospital Escuela en Tegucigalpa (Honduras) durante el periodo 2010-2022. Materiales y métodos. Se llevó a cabo un estudio descriptivo, transversal y analítico. El diagnóstico de laboratorio consistió en el análisis de muestras de heces con los métodos directo y Baermann modificado. Se estimaron frecuencias y porcentajes, y la asociación estadística se calculó con razón de prevalencia e intervalos de confianza del 95 %. Se utilizaron los programas R, versión 4.2.0, y el paquete epiR, versión 2.0.46, para ejecutar los análisis estadísticos. Resultados. La frecuencia general de estrongiloidiasis fue 0,29 % (112/38.085). Dicha frecuencia de detección fue mayor con el método de Baermann modificado (0,87 %; 40/4.575), entre pacientes masculinos (0,44 %; 70/15.758). También fue mayor en el rango de edad 20-40 años (0,41%; 28/6.886) por examen directo y entre los 41-61 años (1,14%; 14/1.232) con el método de Baermann modificado. Entre los factores asociados con la estrongiloidiasis se encontraron: edad entre los 20 y los 61 años (RP=2,26; IC 95%=1,53-3,31), sexo masculino (RP=2,34; IC95%=1,60-3.44), moco (RP=1,86; IC 95%=1,22-2,83) y cristales de Charcot-Leyden en heces (RP=8,47, IC 95%=5,14-13,96), heces líquidas (RP=2,39, IC 95%=1,55-3,68) y otras helmintiasis (RP=6,73, IC 95%=3,98-11,38). Como factores asociados a los casos detectados con el método de Baermann modificado están consulta externa (RP=4,21, IC 95%=1,91-9,28) y heces formadas (RP=3,99, IC 95%=1,94-8,19). Conclusiones. El método de Baermann modificado aumentó la frecuencia de detección de estrongiloidiasis casi cuatro veces. La mayoría de los casos se distribuyeron entre pacientes masculinos adultos. Los casos diagnosticados exclusivamente con el método de Baermann modificado tuvieron diferencias con los casos diagnosticados por examen directo. Es necesario realizar estudios poblacionales.

Frequency of strongyloidiasis and associated factors: Analysis of 13 years of laboratory results in a tertiary referral hospital in Honduras, 2010-2022. / Frecuencia de estrongiloidiasis y factores asociados: análisis de 13 años de resultados de laboratorio en un hospital de tercer nivel de Honduras, 2010-2022

INTRODUCTION: The frequency of detected strongyloidiasis is affected by the selected laboratory method in the studied population. Considering that Honduras has few community-based studies, the analysis of the laboratory record data can provide information helping to understand this parasitosis. OBJECTIVE: To estimate the frequency and to identify the factors associated with strongyloidiasis, analyzing the laboratory records of the Servicio de Parasitología at Hospital Escuela in Tegucigalpa (Honduras) between 2010 and 2022. MATERIALS AND METHODS: We carried out a descriptive, cross-sectional, analytical study. The laboratory diagnosis consisted of stool samples' examination by direct smear and modified Baermann technique. We estimated frequencies and percentages. The statistical association was calculated with prevalence ratios and a 95% confidence interval. Software R, version 4.2.0, and epiR package, version 2.0.46, were used to perform the analysis. RESULTS: The frequency of strongyloidiasis was 0.29% (112/38,085). It was higher with the modified Baermann technique (0.87%; 40/4,575) among male patients (0.44%; 70/15,758). Regarding the age, strongyloidiasis was higher in the 20-40 years old group (0.41%; 28/6,886) with direct smear and 41-61 years old (1.14%; 14/1,232) group with the modified Baermann technique. Among the factors associated with strongyloidiasis were age between 20 and 61 years old (PR=2.26, CI 95%=1.53-3.31), male patients (PR=2.34, CI 95%=1.60­3.44), mucus (PR=1.86, CI 95%=1.22-2.83) and Charcot-Leyden crystals in stool (PR=8.47, CI 95%=5.14-13.96); watery stool (PR=2.39, CI 95%=1.55-3.68), and other helminthiases (PR=6.73, CI 95%=3.98-11.38). Associated factors to cases detected with the modified Baermann technique were outpatient consultation (PR=4.21, CI 95%=1.91-9.28) and formed stools (PR=3.99, CI 95%=1.94-8.19). CONCLUSIONS: The modified Baermann technique increased the detection of strongyloidiasis almost four times. Most cases were distributed among male adults. The cases diagnosed exclusively with the modified Baermann technique have differences from those with observed larvae in the direct smear. It is necessary to develop community-based population studies.

Introducción: La detección de estrongiloidiasis depende del método de diagnóstico utilizado y la población estudiada. Dado que en Honduras hay pocos estudios poblacionales, el análisis de los datos de laboratorio puede generar información que ayude a entender esta parasitosis. Objetivo: Estimar la frecuencia e identificar los factores asociados a la estrongiloidiasis mediante el análisis de los registros de laboratorio del Servicio de Parasitología del Hospital Escuela en Tegucigalpa (Honduras) durante el periodo 2010-2022. Materiales y métodos: Se llevó a cabo un estudio descriptivo, transversal y analítico. El diagnóstico de laboratorio consistió en el análisis de muestras de heces con los métodos directo y Baermann modificado. Se estimaron frecuencias y porcentajes, y la asociación estadística se calculó con razón de prevalencia e intervalos de confianza del 95 %. Se utilizaron los programas R, versión 4.2.0, y el paquete epiR, versión 2.0.46, para ejecutar los análisis estadísticos. Resultados: La frecuencia general de estrongiloidiasis fue 0,29 % (112/38.085). Dicha frecuencia de detección fue mayor con el método de Baermann modificado (0,87 %; 40/4.575), entre pacientes masculinos (0,44 %; 70/15.758). También fue mayor en el rango de edad 20-40 años (0,41%; 28/6.886) por examen directo y entre los 41-61 años (1,14%; 14/1.232) con el método de Baermann modificado. Entre los factores asociados con la estrongiloidiasis se encontraron: edad entre los 20 y los 61 años (RP=2,26; IC 95%=1,53-3,31), sexo masculino (RP=2,34; IC 95% =1,60-3.44), moco (RP=1,86; IC 95%=1,22-2,83) y cristales de Charcot-Leyden en heces (RP=8,47, IC 95%=5,14-13,96), heces líquidas (RP=2,39, IC 95%=1,55-3,68) y otras helmintiasis (RP=6,73, IC 95%=3,98-11,38). Como factores asociados a los casos detectados con el método de Baermann modificado están consulta externa (RP=4,21, IC 95%=1,91-9,28) y heces formadas (RP=3,99, IC 95%=1,94-8,19). Conclusiones: El método de Baermann modificado aumentó la frecuencia de detección de estrongiloidiasis casi cuatro veces. La mayoría de los casos se distribuyeron entre pacientes masculinos adultos. Los casos diagnosticados exclusivamente con el método de Baermann modificado tuvieron diferencias con los casos diagnosticados por examen directo. Es necesario realizar estudios poblacionales.