Innovative approaches to improve serodiagnosis of Strongyloides stercoralis infection

ABSTRACT Strongyloidiasis is a helminthiasis of neglected condition that has no gold standard parasitological diagnosis due to the intermittent release of larvae in feces. This study aimed to use an scFv (single chain variable fragment) obtained by Phage Display, previously validated to detect immune complexes in serum samples from individuals infected with Strongyloides stercoralis by enzyme-linked immunosorbent assay (ELISA). Now the ability of scFv to detect the immune complexes was verified by immunofluorescence, flow cytometry using magnetic beads and surface plasmon resonance (SPR). As ELISA, the SPR, immunofluorescence and flow cytometry demonstrated the ability of scFv to detect immune complexes in sera from individuals with strongyloidiasis and discriminate them from sera of individuals with other parasitic diseases and healthy individuals. Besides de conventional ELISA, the novel approaches can also be promptly applied as auxiliary diagnostic tools to the existing parasitological method for accurate diagnosis of human strongyloidiasis.

How a discerning cytological examination can aid in the diagnosis of infectious diseases: case reports

Infections caused by uncommon and resistant pathogens in unusual sites have been increasingly reported in medical literature. We describe four cases of rare cytological findings and clinical impact for patients. In the first case, Aspergillus sp and Pneumocystis jirovecii were observed in the bronchoalveolar lavage of a patient with severe systemic lupus. In the second and third cases, we describe the presence of Trichomonas sp and Strongyloides sp larvae in samples of pleural and peritoneal fluid, respectively. The fourth report is about a patient with a wrist subcutaneous nodule whose synovial aspiration and cytology revealed the presence of brown septate hyphae. The early identification of the infectious agent in the cytological examination was essential for the introduction and/or re-adaptation of therapy in the four cases described. Patients in this report were immunocompromised with severe comorbidities, conditions often associated with unfavorable clinical outcomes.

Hemorragia digestiva ocasional em criança por estrongiloidíase: importância do exame parasitológico / Occasional digestive hemorrhage in children due to strongyloidiasis: importance of parasitologic testing

RESUMO Objetivo: Descrever um caso incomum de infecção por Strongyloides stercoralis (S. stercoralis) em paciente de quatro meses de idade e ressaltar a importância do diagnóstico precoce. Descrição do caso: Paciente masculino, procedente e residente de Videira, Santa Catarina, Brasil, nasceu pré-termo, parto cesárea, peso de nascimento 1.655 g, e permaneceu na Unidade de Terapia Intensiva neonatal e intermediária por 20 dias. Aos quatro meses de idade, começou a evacuar fezes sanguinolentas e foi feita hipótese de alergia à proteína do leite de vaca, em razão da sintomatologia e do uso da fórmula infantil para o primeiro semestre, para o qual foi indicada a substituição por fórmula infantil com proteína hidrolisada. Foram solicitados a pesquisa de leucócitos e o exame parasitológico das fezes). Ambos se mostraram positivos e o parasitológico revelou a presença de larva rabditoide de S. stercoralis. O clínico manteve a hipótese inicial e a dieta, mas solicitou a coleta de três amostras de fezes, que resultaram em uma amostra para larvas rabditoide, em muda, de S. stercoralis. Como a criança apresentava dor abdominal, vômito e as fezes permaneciam sanguinolentas, foi iniciado o tratamento com tiabendazol - duas vezes/dia por dois dias -, repetido após sete dias, e, em seguida, realizado o exame parasitológico de fezes, tendo sido negativo. Comentários: A estrongiloidíase, apesar de ser uma infecção parasitária frequentemente leve, em pacientes imunocomprometidos pode se apresentar de forma grave e disseminada. Deve-se suspeitar desse agente em pacientes que vivem em áreas endêmicas, sendo o diagnóstico estabelecido por meio da pesquisa das larvas do S. stercoralis na secreção traqueal e nas fezes.

ABSTRACT Objective: To describe an uncommon case of infection by Strongyloides stercoralis (S. stercoralis) in a 4-month-old child and to highlight the importance of early diagnosis. Case description: The patient was a male child from the city of Videira, State of Santa Catarina, Southern Brazil, who was born preterm by Cesarean-section, weighing 1,655 g, and stayed in the neonatal intensive care unit for 20 days. At four months of age, the child started presenting blood in stools and the possibility of cow's milk protein allergy was considered, given the symptoms and the use of infant formula in his 1st semester of life, which was then replaced by infant formula with hydrolyzed protein. White blood cell count and a parasitological stool sample were requested. Both tested positive and the stool ova and parasite examination showed a rhabditoid larva of S. stercoralis. The clinician maintained the initial hypothesis and diet, but requested three new stool samples, which tested positive for rhabditoid larvae of S. stercoralis. Since the child presented abdominal pain and vomiting, and there was still blood in stools, treatment with thiabendazole was initiated twice a day for two days. Treatment was repeated after seven days along with a new parasitological examination, which was then negative. Comments: Although strongyloidiasis is usually a mild parasitic infection, it may be severe and disseminated in immunocompromised patients. This agent must be considered in patients who live in endemic areas, and the diagnosis should be established by searching S. stercoralis larvae in tracheal secretions and in stools.

Screening of Strongyloides infection using an ELISA test in transplant candidates

OBJECTIVES: Hyperinfection or disseminated strongyloidiasis has been frequently reported after transplants and is related to high mortality. This study aimed to screen for strongyloidiasis using serological diagnoses in transplant candidates. METHODS: An ELISA test was performed with filariform larvae of Strongyloides venezuelensis as a source of antigen. RESULTS: In the serum from transplant candidates, anti-Strongyloides IgG antibodies were detected in 35/150 (23.3%) samples by soluble fractions in phosphate buffered saline (PBS), 31/150 (20.7%) samples by soluble fractions in Tris-HCl, 27/150 (18.0%) samples by membrane fractions in PBS and 22/150 (14.7%) samples by membrane fractions in Tris-HCl. CONCLUSIONS: The present results suggest the ELISA test, ideally using soluble fractions of filariform larvae S. venezuelensis in PBS, as an additional strategy for the diagnosis of strongyloidiasis in transplant candidates.

Estrongiloidiasis gastrointestinal en paciente inmunocompetente: a propósito de un caso / Gastrointestinal strongyloidosis in an immunocompetent patient: a case report

Intestinal parasitic infections cause a not insignificant number of chronic diarrhea in children, however, with the sociodemographic change that our country has experienced, the number of cases and new parasites (immigration from tropical endemic areas) could increase. We report the case of an immunocompetent patient who presents with chronic diarrhea associated with Strongyloides stercoralis infection. The patient migrated two years ago from an endemic area for this helminth. The diagnosis is challenging, and the chances of a successful outcome depend on the administration of the antiparasitic.

Las infecciones parasitarias intestinales provocan un número no despreciable de causas de diarrea crónica en niños, sin embargo, con el cambio sociodemográfico que ha vivido nuestro país se podría incrementar el número de casos y de nuevos parásitos (inmigración de áreas endémicas tropicales). Reportamos el caso de un paciente inmunocompetente, que presenta cuadro de diarrea crónica asociada a infección por Strongyloides stercoralis. El paciente habría migrado hace dos años desde zona endémica para este helminto. El diagnóstico es desafiante y las posibilidades de un resultado exitoso dependen de la administración del antiparasitario.

Seroepidemiological aspects of human infection by Strongyloides stercoralis in Alfenas, southern Minas Gerais, Brazil

Abstract INTRODUCTION: In most Strongyloides stercoralis infected individuals, nematoidosis occurs asymptomatically, but in immunocompromised patients, it can cause hyperinfection. Serological techniques seem to be a good alternative for detecting this parasite. METHODS The frequency of seropositivity for strongyloidiasis in Alfenas, MG, was estimated using the enzyme linked immunosorbent assay on blood samples, between May and August of 2015. RESULTS: Out of 258 samples tested, 53.9% were positive, and the frequency of seropositive individuals was higher in the peripheral districts of the municipality. CONCLUSIONS: The results indicate high seropositivity rates for strongyloidiasis among the residents of Alfenas city.

Strongyloidiasis in humans: diagnostic efficacy of four conventional methods and real-time polymerase chain reaction

Abstract INTRODUCTION: Strongyloides stercoralis is an intestinal parasitic nematode that causes hyperinfection and/or a dissemination syndrome in hosts, which is often difficult to diagnose. This study aims to compare the diagnostic efficacy of four conventional methods used to diagnose strongyloidiasis with real-time polymerase chain reaction (qPCR) to detect S. stercoralis in fecal samples. METHODS: We analyzed 143 fecal samples collected from Colombian regions with varying degrees of risk for intestinal infections caused by S. stercoralis to assess the validity, performance, overall efficiency, and concordance of the qPCR using a direct stool test, modified Ritchie concentration technique, agar plate culture, and Harada-Mori technique as reference tests. RESULTS While four fecal samples were positive for S. stercoralis using conventional methods, 32 were positive via qPCR. The diagnostic sensitivity of the qPCR was 75% [95% confidence interval (CI): 20.07-100%], whereas its specificity, negative predictive value, negative likelihood ratio, and Youden's J index were 78.42% (95% CI: 71.22-85.62%), 99.09% (95% CI: 96.86-100%), 0.32 (95% CI: 0.06-1.74), and 0.53, respectively. In addition, the estimated kappa index between the qPCR and the conventional methods was 0.12 (95% CI: -0.020-0.26). CONCLUSIONS: The diagnostic sensitivity of qPCR to detect strongyloidiasis is analogous to that of conventional parasitology methods, with an additional advantage of being capable of identifying the parasite DNA at low sample concentrations.

Linfoma duodenal asociado a infección por Strongyloides stercoralis. Dos manifestaciones de la infección por HTLV-1 / Duodenal Lynphoma associated to Strongyloides stercoralis infection. Two types of HTLV-1 infection

La infección por el virus linfotrópico de células T humanas tipo 1 (HTLV-1), es causante de la leucemia/linfoma de células T del Adulto (ATLL), siendo la afectación duodenal poco usual. La coinfección de HTLV-1 con Strongyloides stercolaris es común en los pacientes con HTLV- 1 debido a la inadecuada respuesta TH2 que presentan estos sujetos. Describimos a una paciente mujer de 48 años de edad, natural y procedente de la selva del Perú con historia familiar de infección por HTLV- 1 quien acude con diarrea crónica y baja de peso. Se le diagnosticó infección por HTLV-1 así como ATLL duodenal y estrongiloidiasis. Se inició tratamiento con ivermectina y quimioterapia, siendo estabilizada y dada de alta. Reportamos el presente caso debido a la poca frecuencia de coexistencia en duodeno de ATLL y estrongiloidiasis.

Infection by the Human T- Lymphotropic virus I (HTLV-1) causes Adult T cell Leukemia-lymphoma (ATLL), being the duodenal involvement rare. Commonly, patients co-infected with HTLV-1 and Strongyloides stercoralis are seen due to the lack of TH2 response found on these patients. We describe a 48-year-old woman, from the jungle of Peru, with a family history of HTLV-1 infection, who presented with a History of chronic diarrhea and weight loss. HTLV-1 infection with ATLL and strongyloidiasis were diagnosed. Ivermectin treatment and chemotherapy were initiated, being stabilized, and discharged. We report this case because of the unusual coexistence in the duodenum of ATLL and strongyloidiasis.

Estrongiloidosis pulmonar / Pulmonary strongyloidiasis

Strongyloidiasis is an infection caused by the parasite Strongyloides stercoralis, which can be asymptomatic and means a high morbidity and mortality in immunocompromised hosts, severe malnutrition and coinfection with HTLV-1 virus. The parasite has the potential to produce and multiply internal autoinfection in humans, thus an hyperinfection can be developed. A case of pulmonary infection by this parasite is presented in this study, infection which advanced into a respiratory failure and required mechanical ventilation and hemodynamic support in an intensive care unit. The standard treatment combined with ivermectin and albendazole was provided, achieving an appropriate response.

La estrongiloidosis es una infección causada por el parásito Strongyloides stercoralis, la cual puede cursar con una alta morbi-mortalidad en pacientes inmunocomprometidos, con desnutrición grave y coinfección con el virus HTLV-1. Se puede desarrollar una hiperinfección, dado que el parásito tiene el potencial de producir una autoinfección interna. Se presenta un caso de infección pulmonar por S. stercoralis que progresó a una falla respiratoria y requirió soporte ventilatorio y hemodinámico en una unidad de cuidados intensivos, suministrándole el tratamiento estándar combinado de ivermectina y albendazol con una respuesta satisfactoria.

Clinical conditions associated withintestinal strongyloidiasis in Rio de Janeiro, Brazil

INTRODUCTION: Strongyloides stercoralis is a soil-transmitted helminth that produces an infection that can persist for decades. The relationships between certain clinical conditions and strongyloidiasis remains controversial. This study aims to identify the clinical conditions associated with intestinal strongyloidiasis at a reference center for infectious diseases in Rio de Janeiro, Brazil. METHODS: The clinical conditions that were assessed included HIV/AIDS, HTLV infection, cardiovascular diseases, diabetes, obstructive respiratory diseases, viral hepatitis, tuberculosis, cancer, chronic renal disease, nutritional/metabolic disorders, psychiatric conditions, rheumatic diseases and dermatologic diseases. We compared 167 S. stercoralis-positive and 133 S. stercoralis-negative patients. RESULTS: After controlling for sex (male/female OR = 2.29; 95% (CI): (1.42 - 3.70), rheumatic diseases remained significantly associated with intestinal strongyloidiasis (OR: 4.96; 95% CI: 1.34-18.37) in a multiple logistic regression model. With respect to leukocyte counts, patients with strongyloidiasis presented with significantly higher relative eosinophil (10.32% ± 7.2 vs. 4.23% ± 2.92) and monocyte (8.49% ± 7.25 vs. 5.39% ± 4.31) counts and lower segmented neutrophil (52.85% ± 15.31 vs. 61.32% ± 11.4) and lymphocyte counts (28.11% ± 9.72 vs. 30.90% ± 9.51) than S. stercoralis-negative patients. CONCLUSIONS: Strongyloidiasis should be routinely investigated in hospitalized patients with complex conditions facilitate the treatment of patients who will undergo immunosuppressive therapy. Diagnoses should be determined through the use of appropriate parasitological methods, such as the Baermann-Moraes technique. .

Membrane fractions from Strongyloides venezuelensis in the immunodiagnosis of human strongyloidiasis / Frações de membrana de Strongyloides venezuelensis para o imunodiagnóstico da estrongiloidíase humana

Strongyloides venezuelensis is a parasitic nematode of rodents frequently used to obtain heterologous antigens for the immunological diagnosis of human strongyloidiasis. The aim of this study was to evaluate membrane fractions from S. venezuelensis for human strongyloidiasis immunodiagnosis. Soluble and membrane fractions were obtained in phosphate saline (SS and SM) and Tris-HCl (TS and TM) from filariform larvae of S. venezuelensis. Ninety-two serum samples (n = 92) were obtained from 20 strongyloidiasis patients (Group I), 32 from patients with other parasitic diseases (Group II), and 40 from healthy individuals (Group III), and were analyzed by enzyme-linked immunosorbent assay (ELISA). Soluble fractions (SS and TS) showed 90.0% sensitivity and 88.9% specificity, whereas the membrane fractions (SM and TM) showed 95.0% sensitivity and 94.4% specificity. The present results suggest the possible use of membrane fractions of S. venezuelensis as an alternative antigen for human strongyloidiasis immunodiagnosis.

Strongyloides venezuelensis é um nematódeo parasita de roedores, frequentemente usado como antígeno heterólogo para o diagnóstico imunológico da estrongiloidíase humana. O objetivo deste estudo foi avaliar frações de membrana de S. venezuelensis para o imunodiagnóstico da estrongiloidíase humana. Para tanto, frações solúveis e de membrana foram obtidas em solução salina fosfato (SS e MS) e Tris-HCl (ST e MT) de larvas filarioides de S. venezuelensis. Amostras de soro de 92 indivíduos, sendo 20 com estrongiloidíase (Grupo I); 32 com outras parasitoses (Grupo II), e 40 indivíduos saudáveis (Grupo III), foram analisadas pelo teste Imunoenzimático (ELISA). As frações solúveis (SS e ST) apresentaram 90,0% e 88,9%, enquanto que as frações de membrana (MS e MT) demonstraram 95,0% e 94,4%, de sensibilidade e especificidade, respectivamente. Os resultados obtidos permitem indicar as frações de membranas como antígeno alternativo para o diagnóstico da estrongiloidíase humana.

HIGH PREVALENCE OF Strongyloides stercoralis INFECTION AMONG THE ELDERLY IN BRAZIL / Alta prevalência da infecção por Strongyloides stercoralis em idosos do Brasil

SUMMARY Little is known about the frequency of intestinal parasites in the elderly due to a lack of attention given to the occurrence of these infections among older adults. This study compares the frequency of Strongyloides stercoralis and other enteroparasites between elderly living in nursing homes (n = 100) and those noninstitutionalized (n = 100) from Uberlândia, state of Minas Gerais, southeastern Brazil, associated with data of epidemiological and socio-demographic conditions. Through coproparasitological examination of both groups, enteroparasites were detected in 15 of 200 individuals examined (7.5%; CI: 5.1- 9.9). S. stercoralis was the most frequent parasite 10/200 (5%; CI: 4.2-5.8), being significantly higher in males and in individuals with autonomy for daily living activities. There were no statistical differences in the prevalence of parasites between the two groups compared. In conclusion, S. stercoralis infection was highly prevalent in elderly patients and it does not depend on whether the individual was institutionalized or not. .

RESUMO Pouco é conhecido sobre a freqüência de parasitas intestinais em idosos devido à falta de atenção dada à ocorrência destas infecções nesta faixa etária. Este estudo compara a freqüência de Strongyloides stercoralis e outros parasitos intestinais entre idosos residindo em lares para idosos (n = 100) e aqueles não institucionalizados (n = 100) de Uberlândia, Minas Gerais, região sudeste do Brasil, associados com dados epidemiológicos e condições sócio-demográficas. Ambos os grupos foram submetidos a exames coproparasitológicos. Parasitos foram detectados em 15 dos 200 indivíduos examinados (7,5%; CI: 5,1 - 9,9). S. stercoralis foi o parasito mais freqüente 10/200 (5%; CI: 4,2 - 5,8), sendo significantemente maior em homens e indivíduos com autonomia das atividades diárias. Não houve diferença estatística entre a prevalência de parasitos quando os dois grupos foram comparados. Concluiu-se que a infecção por S. stercoralis foi altamente prevalente em idosos independente se institucionalizados ou não. .

Modified Formalin-Ether Concentration Technique for Diagnosis of Human Strongyloidiasis

We compared the efficacy and applicability of a modified formalin-ether concentration technique (M-FECT) to the conventional FECT (C-FECT) and the agar plate culture (APC) method for the detection of Strongyloides stercoralis larvae. For this purpose, we used 600 human fecal specimens collected in an endemic area of southern Thailand. In the M-FECT, we used 2 layers of wire meshes, instead of gauze, to avoid the loss by absorption/adhesion of larvae to the gauze during filtration, and we reduced the exposure time of S. stercoralis larvae in stool samples to formalin. By such simple modifications, the efficacy of M-FECT has become comparable to APC and was much better than that of C-FECT for the diagnosis of strongyloidiasis.

Salvage treatment of disseminated strongyloidiasis in an immunocompromised patient: therapy success with subcutaneous ivermectin

Disseminated strongyloidiasis is a disease with high mortality rate, especially in immunocompromised individuals. Paralytic ileus and intestinal malabsorption are frequent symptoms caused by this severe disease. As there are no licensed parenteral anthelmintic drugs for human use, off-label formulations are often used in the treatment of this disease. In this case report, the use of subcutaneous ivermectin is described as a successful therapy for this life-threatening infection.

Fatal disseminated strongyloidiasis after kidney transplantation / Estrongiloidíase disseminada fatal após transplante renal

Disseminated strongyloidiasis (DS) is a rare and severe parasitic disease that is difficult to recognize and affects immunocompromised individuals. We report the case of a kidney transplant recipient who presented with DS despite prophylaxis with albendazole. We have discussed the need for better prophylactic strategies and for a higher degree of suspicion in order to diagnose DS.

A estrongiloidíase disseminada (ED) é uma doença parasitária rara de difícil diagnóstico que acomete indivíduos imunocomprometidos. Relatamos um caso de um paciente transplantado renal que desenvolveu ED apesar do uso de profilaxia com albendazol. São discutidas estratégias profiláticas e de diagnóstico da estrongiloidíase disseminada.

Estrongiloidosis diseminada en un paciente con SIDA / Disseminated strongyloidiasis in an AIDS patient / Estrongiloidíase disseminada em um paciente com AIDS

Se comunica un caso de hiperinfección por Strongyloides stercoralis diagnosticado a partir de una secreción respiratoria obtenida por lavado broncoalveolar (LBA). El paciente, oriundo de una región endémica (Paraguay), VIH positivo (50 linfocitos T CD4+/µL en sangre venosa periférica) se internó por un cuadro pulmonar, presuntivamente identificado como neumocistosis pulmonar (PCP). La microscopia en fresco del concentrado de las secreciones respiratorias reveló larvas rabditoides y filariformes de Strongyloides stercoralis. En la microscopia con tinta china del LCR se observaron levaduras capsuladas (por cultivo Criptococcus neoformans) y la determinación del antígeno polisacárido capsular de C. neoformans fue de 1/1000 en sangre y 1/10 en LCR. El estudio virológico por PCR del LCR fue positivo para citomegalovirus, mientras que el estudio parasitológico del mismo fue negativo, al igual que el examen micológico de las secreciones respiratorias. Tras el diagnóstico parasitológico comenzó el tratamiento con ivermectina (200 µg/kg/día vía oral), el cual resultó ineficaz, tal como lo determinó la presencia de larvas móviles en la microscopia de una muestra de aspirado traqueal. El paciente falleció 3 días después.

A case of Strongyloides stercoralis hyperinfection diagnosed from respiratory secretions obtained by bronchoalveolar lavage (BAL) is communicated. The patient, born in an endemic region (Paraguay), HIV positive (50 T CD4+ lymphocytes/µL), was hospitalized with respiratory pathology, presumptively suspected as pulmonary pneumocystosis (PCP). Fresh microscopy of the respiratory secretions concentrate revealed filariform and rabditoide larvae of Strongyloides stercoralis. India ink microscopy of CSF showed capsulated yeasts (Criptococcus neoformans by culture). The titles bron of polysaccharide capsular antigen of C. neoformans were 1/1.000 in blood and 1/10 in CSF. Virological study of CSF by PCR was positive for citomegalovirus, and parasitological examination was negative, as well as the mycological study of respiratory secretions. After diagnosis, treatment with ivermectin (200 µg/kg/day) was started, which proved ineffective, as was determined by the presence of multiple motile larvae in the microscopy of a tracheal lavage. The patient died 3 days later.

Comunica-se um caso de hiperinfecção por Strongyloides stercoralis diagnosticado a partir de uma secreção respiratória obtida através de lavagem broncoalveolar (LBA). O paciente, originário de uma região endêmica (Paraguai), HIV positivo (50 linfócitos T CD4+/µL em sangue venoso periférico) foi hospitalizado devido a um quadro pulmonar, presuntivamente identificado como pneumocistose pulmonar (PCP). A microscopia em fresco da concentração das secreções respiratórias revelou larvas rabditoides e filariformes de Strongyloides stercoralis. Na microscopia com tinta nanquim do LCR foram observadas leveduras capsuladas (por cultura Criptococcus neoformans) e a determinação do antígeno polissacarídeo capsular de C. neoformans foi de 1/1000 em sangue e 1/10 em LCR. O estudo virológico por PCR do LCR foi positivo para Citomegalovirus, enquanto que o estudo parasitológico do mesmo foi negativo, do mesmo modo que o exame micológico das secreções respiratórias. Após o diagnóstico parasitológico começou o tratamento com ivermectina (200 µg/kg/día vo), o qual resultou ineficaz, tal como foi determinado pela presença de larvas móveis na microscopia de uma amostra de aspiração traqueal. O paciente faleceu 3 dias depois.

Rare case of strongyloides stercoralis hyperinfection in a Greek patient with chronic eosinophilia

Strongyloidiasis is a disease characterized by a diverse spectrum of unspecific manifestations that complicate its diagnosis. Although, the course of its chronic form is usually benign, in cases of immunosuppression, iatrogenic or not, it can evolve to a hyperinfection syndrome with even fatal complications. Herein, we report a case of Strongyloides stercoralis hyperinfection in a Greek patient receiving corticosteroid treatment for chronic eosinophilia and angioedema. The case represents an extremely rare case of autochthonous strongyloidiasis in Greece and underlines the importance of the early diagnosis of the disease's uncomplicated forms in order to prevent its severe sequelae.