Identification of a nuclear receptor/coactivator developmental signaling pathway in the nematode parasite Strongyloides stercoralis.

DAF-12 is nematode-specific nuclear receptor that has been proposed to govern development of the infectious stage of parasitic species, including Strongyloides stercoralis Here, we identified a parasite-specific coactivator, called DAF-12 interacting protein-1 (DIP-1), that is required for DAF-12 ligand-dependent transcriptional activity. DIP-1 is found only in Strongyloides spp. and selectively interacts with DAF-12 through an atypical receptor binding motif. Using CRISPR/Cas9-directed mutagenesis, we demonstrate that DAF-12 is required for the requisite developmental arrest and the ligand-dependent reactivation of infectious S. stercoralis infective third-stage larvae, and that these effects require the DIP-1 coactivator. These studies reveal the existence of a distinct nuclear receptor/coactivator signaling pathway that governs parasite development.

Helminth-microbiota cross-talk - A journey through the vertebrate digestive system.

The gastrointestinal (GI) tract of vertebrates is inhabited by a vast array of organisms, i.e., the microbiota and macrobiota. The former is composed largely of commensal microorganisms, which play vital roles in host nutrition and maintenance of energy balance, in addition to supporting the development and function of the vertebrate immune system. By contrast, the macrobiota includes parasitic helminths, which are mostly considered detrimental to host health via a range of pathogenic effects that depend on parasite size, location in the GI tract, burden of infection, metabolic activity, and interactions with the host immune system. Sharing the same environment within the vertebrate host, the GI microbiota and parasitic helminths interact with each other, and the results of such interactions may impact, directly or indirectly, on host health and homeostasis. The complex relationships occurring between parasitic helminths and microbiota have long been neglected; however, recent studies point towards a role for these interactions in the overall pathophysiology of helminth disease, as well as in parasite-mediated suppression of inflammation. Whilst several discrepancies in qualitative and quantitative modifications in gut microbiota composition have been described based on host and helminth species under investigation, we argue that attention should be paid to the systems biology of the gut compartment under consideration, as variations in the abundances of the same population of bacteria inhabiting different niches of the GI tract may result in varying functional consequences for host physiology.

Impacto da infecção por HTLV-1 nas manifestações clínicas e no tratamento de pacientes com estrongiloidíase / Impact of HTLV-1 infection on clinical presentations and treatment of strongyloidiasis patients

A estrongiloidíase é uma enfermidade que acomete cerca de 100 milhões de pessoas em todo mundo. Essa parasitose apresenta alta prevalência e tem maior gravidade clínica entre indivíduos imunossuprimidos, principalmente aqueles portadores do vírus linfotrópico de células T humana tipo 1 (HTLV). Este fato torna a coinfecção por esse vírus em pacientes parasitados por Strongyloides stercoralis um grave problema de saúde pública. O presente estudo teve por objetivo revisar os estudos sobre coinfecção por HTLV/S. stercoralis. Foi realizada busca eletrônica completa de dados disponíveis sobre a coinfecção entre o vírus e S. stercoralis. As publicações foram capturadas a partir das bases de dados PubMed e SciELO, sendo utilizados os seguintes descritores "vírus linfotrópico de células T humanas tipo 1", "HTLV-1", "S. stercoralis" e "estrongiloidiase". A infecção por HTLV em pacientes parasitados representa fator de risco para o desenvolvimento de estrongiloidíase grave e, nesses indivíduos, o tratamento recomendado deve ser realizado e monitorado para garantir o sucesso terapêutico.(AU)

Strongyloidiasis is a disease that affects approximately 100 million people worldwide. This parasitosis is highly prevalent and more clinically severe among immunosuppressed individuals, particularly those with Human T-lymphotropic virus 1 (HTLV-1). This fact makes the co-infection with this virus in patients parasitized by Strongyloides stercoralis a serious public health problem. The present study aimed at reviewing the studies of co-infection with HTLV/S. stercoralis. A complete electronic search for available data about the co-infection of the virusand S. stercoralis was performed. The publications were obtained from the databases PubMed and SciELO, with the following descriptors being used: "Human T-lymphotropic Virus type 1, "HTLV-1", S. stercoralis, and "strongyloidiasis". The infection with HTLV in infected patients is a risk factor for the development of severe strongyloidiasis, and for these individuals the recommended treatment should be performed and monitored to ensure therapeutic success.(AU)

Serious Neurological Adverse Events after Ivermectin-Do They Occur beyond the Indication of Onchocerciasis?

Serious neurological adverse events have been reported from large scale community-based ivermectin treatment campaigns against Onchocerciasis volvulus in Africa. The mechanism of these events has been debated in the literature, largely focusing on the role of concomitant infection with Loa loa versus the presence of mdr-1 gene variants in humans allowing ivermectin penetration into the central nervous system. A case series of serious neurological adverse events occurring with the use of ivermectin outside of the onchocerciasis indication has been identified in VigiBase, an international database of suspected adverse drug reactions. Forty-eight cases have been reported from multiple countries in which ivermectin has been prescribed for multiple indications; clinical review excluded 20 cases with more probable explanations or other exclusion criteria. Within the remaining 28 cases, there is supportive evidence for a causative role of ivermectin including presence of the drug in brain tissue in one case and recurrence of symptoms on repeated exposure in three cases. This series suggests that serious neurological adverse events observed with the use of ivermectin in the treatment of onchocerciasis may not be entirely explained by concomitant high burden loiasis infections. By comparison with the extensive post marketing experience with ivermectin in the successful treatment of parasitic infections, the number of reported cases suggests that such events are likely rare. However, elucidation of individual-level risk factors could contribute to therapeutic decisions that can minimize harms. Further investigation into the potential for drug-drug interactions and explorations of polymorphisms in the mdr-1 gene are recommended.

Strongyloides hyper infection in a steroid dependent leprosy patient.

Background: Immunosuppresion caused by corticosteroids predisposes leprosy patients to Strongyloides stercoralis infection which if untreated can be fatal. Patients acquire infection by walking barefoot in infested soils and can be infected for life because of the auto infective cycle of the parasite. Corticosteroids have precipitated death in more than 60% of disseminated strongyloidiasis cases. Objective: The aim of this article is to report a successfully treated case of SS infection in a low resourceleprosy hospital in rural India and increase awareness of the unique features of S. stercoralis and also to outline the important role that dermatologists and leprologists have in diagnosing and treating chronic strongyloidiasis, thus preventing cases of fatal hyperinfection. Discussion: Leprosy patients live in tropics and subtropics which are also endemic for SS infestation and hence are prone to develop this infection. Chronic strongyloidiasis does not have typical symptoms and clinical features. Those who have unexplained eosinophilia must be checked for the presence of the parasite before initiation of steroid therapy for reactions and neuritis. Leprosy heath workers must have the awareness and a high index of suspicion to diagnose disseminated SS infection. Otherwise these patients, if infected, may develop hyperinfection syndrome, which has a high fatality rate.

Diagnóstico y tratamiento de la estrongiloidosis / Diagnosis and treatment of strongyloidosis

Con el propósito de determinar las evidencias más recientes en torno a la estrongiloidosis, se realizó una revisión en bases de datos electrónicas sobre el tema, particularizando en los trabajos de los últimos 5 años. Strongyloides stercoralis es un nemátodo intestinal de distribución global, particularmente, en regiones tropicales y subtropicales. El parásito presenta un ciclo de vida complejo dada la posibilidad de desarrollarlo de manera directa, indirecta o producir auto- infecciones internas o externas. La infección puede mantenerse por muchos años sin que el individuo afectado refiera manifestaciones clínicas atribuibles al parásito; sin embargo, en algunos casos, especialmente inmunocomprometidos, la parasitosis puede desencadenar manifestaciones clínicas que varían desde cuadros ligeros de dolor abdominal y/o diarrea hasta episodios diarreicos debilitantes que ocasionan malabsorción, pérdida de peso y desgaste crónico. Se expone una revisión sobre el parásito, la forma cómo se relaciona con el humano y consideraciones sobre el diagnóstico, tratamiento y manejo de los pacientes infectados. En Cuba está presente esta entidad y existen los medios apropiados para su diagnóstico y tratamiento(AU)

To determine the more current evidences en relation to strongyloidosis, a review in electronic databases on this subject, characterizing on the papers from the past years. Strongyloides stercoralis is an intestinal nematode of global distribution, mainly in tropical and subtropical regions. The parasite has a complex life cycle due to possibility of a direct and indirect development or to produce internal and external autoinfections. The infection may to remains for many years without the involved subject refers clinical manifestations attributable to parasite; however, in some cases, specially those immunocompromised, parasitosis may to trigger clinical manifestations changing from slights pictures of abdominal pain and/or diarrhea up to debilitating diarrheic episodes causing a malabsorption syndrome, loss of weight and chronic wear an tear. It was showed the results of a review on the parasite, the way how it is related to human being and the considerations on the diagnosis, treatment and management of infected patients. In Cuba this entity is present and there are appropriate means for its diagnosis and treatment(AU)

Spatial distribution of soil-transmitted helminths, including Strongyloides stercoralis, among children in Zanzibar.

A programme periodically distributing anthelminthic drugs to school-aged children for the control of soiltransmitted helminthiasis was launched in Zanzibar in the early 1990s. We investigated the spatial distribution of soiltransmitted helminth infections, including Strongyloides stercoralis, in 336 children from six districts in Unguja, Zanzibar, in 2007. One stool sample per child was examined with the Kato-Katz, Koga agar plate and Baermann methods. The point prevalence of the different helminth infections was compared to the geological characteristics of the study sites. The observed prevalences for Trichuris trichiura, Ascaris lumbricoides, hookworm and S. stercoralis were 35.5%, 12.2%, 11.9% and 2.2%, respectively, with considerable spatial heterogeneity. Whilst T. trichiura and hookworm infections were found in all six districts, no A. lumbricoides infections were recorded in the urban setting and only a low prevalence (2.2%) was observed in the South district. S. stercoralis infections were found in four districts with the highest prevalence (4.0%) in the West district. The prevalence of infection with any soil-transmitted helminth was highest in the North A district (69.6%) and lowest in the urban setting (22.4%). A. lumbricoides, hookworm and, with the exception of the North B district, S. stercoralis infections were observed to be more prevalent in the settings north of Zanzibar Town, which are characterized by alluvial clayey soils, moist forest regions and a higher precipitation. After a decade of large-scale administration of anthelminthic drugs, the prevalence of soil-transmitted helminth infections across Unguja is still considerable. Hence, additional measures, such as improving access to adequate sanitation and clean water and continued health education, are warranted to successfully control soil-transmitted helminthiasis in Zanzibar.

Optimum methods of inactivation of Strongyloides stercoralis larvae from reclaimed wastewater.

Strongyloidiasis presents a major health hazard when reusing wastewater. Albendazol with a concentration of 4 mg/l, a contact time of 45 min, pH 1.2 and pH 10.2, killed the larva. The larva was also killed with a 0.03% concentration of iodine and a detention time of 30 min or a 0.04% concentration of iodine and a contact time of 10 min. The required detention time to inactivate larva in water was found to be 17 days. The minimum revealed residual chlorine to kill the larvae was 4 mg/l with 120 min of detention time, and a minimum contact time was found to be 80 min with a residual of 23 mg/l. Many methods are available to inactivate the Strongyloides stercoralis, which could be acids, alkaline chemicals, larvicidal chemicals, super chlorination, or just detention time. The best method must be determined according to the prevailing specific environmental site and the feasibility of the selected method(s).

Prevalence of helminth ova in soil samples from public places in Shiraz.

To determine the prevalence of helminth eggs in public places and children's playgrounds, 112 soil samples were collected in 26 sites in Shiraz, southern Islamic Republic of Iran, during September 2002-September 2003. Toxocara cati ova were found in 7 (6.3%) samples, 2 had Ascaris lumbricoides ova, 3 had larvae morphologically similar to Strongyloides stercoralis. Coccidia oocysts were also observed in 4 samples. No contamination was observed during the dry season.

Consequências clínicas e imunológicas da co-infecção HTLV-1 e helmintos / Clinical and immunological consequences of co-infection HTLV-1 and helminth

Estudos prévios têm mostrado que a infecção pelo HTLV-I pode resultar em uma ativação e proliferação linfocitária, e uma exacerbada resposta imune Th1 com níveis altos de IFN-y. A infecção por helmintos está relacionada com produção de IgE e citocinas com um perfil Th2. Neste trabalho foi caracterizada a resposta imune de portadores de HTLV-1 e de pacientes com mielopatia asssociada ao HTLV-1 e a influência da infecção pelo HTLV-I no curso clínico e na resposta imune de pacientes com estrongiloidíase e esquistossomos. Adcionalmente, foi avaliada a influência da infecção por he1mintos na resposta imune (determinação de citocinas em sobrenadante e análise por FACS) e na carga proviral de indivíduos infectados pelo HTLV-I. Foi observado que indivíduos com mielopatia apresentaram níveis de citocinas pro-inflamatórias, especificamente o IFN-y, bem mais altos do que portadores assintomáticos, porém neste último grupo houve uma variação nestes níveis e 40% destes indivíduos tiveram níveis semelhantes aos pacientes com mielopatia. Além disso, os pacientes com mielopatia apresentaram maior proliferação linfocitária e maior freqüência de células T CD8+. Quando foi avaliada a influência do HTLV-1 na resposta imune ao S. stercoralis, foi documentado que pacientes com estrongiloidíase quando co-infectados pelo HTLV-1 apresentaram níveis mais baixos de IL-5, IL-13 e níveis mais altos de IFN-y do que pacientes que apresentavam somente estrongiloidíase. Estes achados podem justificar o fato de que pacientes co-infectados pelo HTLV-1 e S. stercoralis desenvolvam formas disseminadas da doença e menor resposta terapêutica a drogas anti-helmínticas. Achados imunológicos semelhantes foram observados em relação à co-infecção com HTLV-1 e S. mansoni. Os pacientes dualmente infectados pelo HTLV-1 e S. mansoni produziram mais IFN-y e menos IL-5, IL-10 e IgE específica para S. mansoni do que pacientes apenas com infecção pelo S. mansoni. A despeito de pacientes com HTLV-1 e...

Parasitological and immunological diagnoses of strongyloidiasis in immunocompromised and non-immunocompromised children at Uberlândia, State of Minas Gerais, Brazil.

Parasitological and immunological diagnoses were part of a study conducted among 151 children, 83 immunocompromised (IC) and 68 non-immunocompromised (non-IC) aged from zero to 12, seen at the University Hospital, Universidade Federal de Uberlândia, State of Minas Gerais, Brazil, from February, 1996, to June, 1998. Three fecal samples from each child were analyzed for the parasitological diagnosis by Baermann-Moraes and Lutz methods. The immunological diagnosis to detect IgG and IgM antibodies was carried out by the indirect immunofluorescence antibody test (IFAT) with cryo-microtome sections of Strongyloides stercoralis and Strongyloides ratti larvae as antigens and by the ELISA test with an alkaline extract of S. ratti as the antigens. Of the 151 children 5 (3.31%) were infected with larvae of S. stercoralis (2 cases IC, 2.41%, and 3 cases non-IC, 4.41%). The IFAT-IgG detected 7 (8.43%) serum samples positive among IC, and 2 (2.94%) cases among non-IC. The ELISA-IgG test detected 10 (12.05%) serum samples positive among IC, and 1 (1.47%) case among non-IC. The IFAT-IgM detected 6 (7.22%) positive cases among IC, and 3 (4.41%) cases among non-IC. ELISA-IgM test detected 10 (12.05%) positive cases among IC, and 3 (4.41%) cases among non-IC. It was concluded that the immunological tests can help in the diagnosis of strongyloidiasis in immunocompromised children.

Parasitological and immunological diagnoses of strongyloidiasis in immunocompromised and non-immunocompromised children at Uberlândia, state of Minas Gerais, Brazil

Parasitological and immunological diagnoses were part of a study conducted among 151 children, 83 immunocompromised (IC) and 68 non-immunocompromised (non-IC) aged from zero to 12, seen at the University Hospital, Universidade Federal de Uberlândia, State of Minas Gerais, Brazil, from February, 1996, to June, 1998. Three fecal samples from each child were analyzed for the parasitological diagnosis by Baermann-Moraes and Lutz methods. The immunological diagnosis to detect IgG and IgM antibodies was carried out by the indirect immunofluorescence antibody test (IFAT) with cryo-microtome sections of Strongyloides stercoralis and Strongyloides ratti larvae as antigens and by the ELISA test with an alkaline extract of S. ratti as the antigens. Of the 151 children 5 (3.31 percent) were infected with larvae of S. stercoralis (2 cases IC, 2.41 percent, and 3 cases non-IC, 4.41 percent). The IFAT-IgG detected 7 (8.43 percent) serum samples positive among IC, and 2 (2.94 percent) cases among non-IC. The ELISA-IgG test detected 10 (12.05 percent) serum samples positive among IC, and 1 (1.47 percent) case among non-IC. The IFAT-IgM detected 6 (7.22 percent) positive cases among IC, and 3 (4.41 percent) cases among non-IC. ELISA-IgM test detected 10 (12.05 percent) positive cases among IC, and 3 (4.41 percent) cases among non-IC. It was concluded that the immunological tests can help in the diagnosis of strongyloidiasis in immunocompromised children

Fluctuations of larval excretion in Strongyloides stercoralis infection.

Follow-up stool examinations were carried out on two groups of the subjects who were screened negative (group 1) or positive (group 2) for Strongyloides stercoralis by the agar plate culture. This technique could detect S. stercoralis larvae in 87.5-96.4% of the subjects in group 2 and 0-5.9% of the subjects in group 1 on various days of the eight-week and four-week follow-up periods, respectively. The detection rate on each day of examination was not statistically different from that on the first day in both groups. Quantitative measurement of S. stercoralis larvae excreted in the feces of the subjects in group 2 by the standard direct smear method of Beaver and others revealed slight to marked fluctuations of the larval output in individual subjects. From the results of both stool examination methods, it could be implied that 52% of S. stercoralis-infected individuals had low-level infection.

Strongyloides stercoralis and other enteroparasites in children at Uberlândia city, state of Minas Gerais, Brazil.

To evaluate the rate of infection by Strongyloides stercoralis and other enteroparasites a survey was conducted in the city of Uberlândia, State of Minas Gerais, Brazil. A total of 900 stool samples from 300 children aging from four months to seven years, randomly selected in ten nursery schools from September 1994 to December 1995, were examined, both by the Baermann-Moraes and Lutz methods. Thirty nine children (13%) were found to be infected by S. stercoralis, 64.1% were boys and 35.9% were girls. Taking all the enteroparasites as a whole the results of the survey pointed out that 265 (88.4%0 of the 300 children were infected by the following: Giardia lamblia, 78.3%; Ascaris lumbricoides, 15.3%; S. stercoralis, 13%; Hymenolepis nana, 6.7%; hookworms, 6%; Enterobius vermicularis, 4%; Hymenolepis diminuta, 4% and Trichuris trichiura, 0.7%. From 265 infected children 64.5% were mono-infected, 27.2% were infected by two parasites and 8.3% had a poly-specific parasite burden. It was concluded that strongyloidiasis is hyperendemic in this area.