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.

ABSTRACT In experimental infection with Strongyloides venezuelensis, the acute and recovery phases can be distinguished, unlike human infections caused by Strongyloides stercoralis. The objective of this study was to evaluate the production of anti-Strongyloides IgG antibodies and the recognition of immunogenic protein bands during the acute and the recovery phases in rats experimentally infected with S. venezuelensis. Rats were infected subcutaneously with 400 or 4,000 S. venezuelensis infective larvae. The acute phase was characterized by elimination of a large number of eggs in the faeces on days 6-14 post infection; the recovery phase was characterized by the resolution of the infection between days 30 and 35 post infection. Differences in IgG levels were observed in the acute and the recovery phases. Different antigenic fractions were recognized in both phases of infection. It is concluded that proteins within the 30-40 kDa range are immunoreactive markers for both the acute and the recovery phases in rats experimentally infected with S. venezuelensis, particularly using membrane antigen.

ABSTRACT Strongyloidiasis is a human parasitic disease caused by the helminth Strongyloides stercoralis whose treatment is particularly difficult in immunosuppressed patients due to their low responsiveness to conventional therapy. Carica papaya and its isolated compounds benzyl isothiocyanate, carpaine and carpasemine are promising compound for the treatment of Strongyloides infections due to their anthelmintic action. This study aims to examine the in vitro ovicidal and larvicidal activity of C. papaya seed hexane extract against Strongyloides venezuelensis, using egg hatching tests and larval motility tests as efficiency markers. The crude extract at the concentrations of 566 – 0.0566 mg/mL or the control with albendazole (0.025 mg/mL) and negative controls (water and PBS) were incubated with an equal volume of egg suspension (± 50 specimens) followed by counting of the specimens after 48 h. The same extract and dilutions were added to L3 larvae suspensions (±50 specimens) followed by analysis of larvae viability after 24, 48, and 72 h. The extract inhibited egg hatching with high efficiency at concentrations of 56.6 mg/mL (95.74%) and 5.66 mg/mL (92.16%). At the concentrations of 566 mg/mL (100%) and 56.66 mg/mL (97.32%), the extract inhibited larval motility as effectively as ivermectin (0.316 mg/mL; 100%), and more effectively than the other dilutions and the negative controls. The larvicidal effect depended on the extract concentration, but not on the treatment period. Therefore, C. papaya seed hexane extract has anthelmintic potential against S. venezuelensis and is a promising compound for the development of phytotherapies to treat strongyloidiasis.

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.

ABSTRACT The Taenia solium cysticercosis affects millions of people worldwide and is considered a public health problem, especially in developing countries. The diagnosis of neurocysticercosis is complex and involves the analysis of epidemiological, clinical, neuroimaging, and immunological host data. Neurocysticercosis is endemic in Brazil, and is related to the cause of death mainly in the Southeast, South, and Central-West regions. The objective of this study was to determine the seroprevalence of cysticercosis in inhabitants of the city of Jataí, Goiás, in the Central-West region of Brazil from April to August 2012. A total of 529 serum samples were analyzed by enzyme-linked immunosorbent assay for detecting IgG antibodies against T. solium larvae, and Western blotting was used for confirming the diagnosis through the recognition of at least two specific peptides from their serum antibodies. The 351/529 (66.3%) reactive samples were analyzed by enzyme-linked immunosorbent assay and Western blotting confirmed the diagnosis in 73 samples that recognized at least two of the following peptides specific IgG antibodies for cysticercosis: 18, 24, 28–32, 39–42, 47–52, 64–68, and 70 kDa. The seroprevalence of cysticercosis was 13.8% (95% CI 5.9–21.7), demonstrating that the studied area is endemic to this disease.

ABSTRACT Latex from Carica papaya is rich in bioactive compounds, especially papain, which may help to control parasitic diseases. This study evaluated the efficacy of latex from C. papaya and purified papain against Strongyloides venezuelensis. The Egg Hatching Test (EHT) and the Larval Motility Test (LMT) using fresh and frozen latex (250mg/mL), lyophilized latex (34mg/mL), and purified papain (2.8 mg/mL) were performed. Albendazole (0.025 mg/mL) and ivermectin (316 ppm) were used as positive controls. EHT and LMT were carried out through the incubation of each solution with S. venezuelensis eggs or larvae (± 100 specimens), and results were analyzed after 48h (EHT) or 24, 48, and 72h (LMT). EHT showed that latex preparations at higher concentrations (1:10 to 1:100) resulted in partial or complete destruction of eggs and larvae inside the eggs. The result from the 1:1,000 dilution was similar to the positive control. LMT showed effectiveness in all the tested dilutions compared to negative controls. Purified papain showed a dose-dependent response in the EHT. Purified papain (2.8 mg/ mL) showed similar results to lyophilized latex at 1:1,000 in the EHT. Latex and purified papain from C. papaya were effective against S. venezuelensis eggs and larvae in vitro, suggesting their potential use as an alternative treatment for strongyloidiasis.

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.

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.

The aim of the present study was to analyse Taenia solium metacestode antigens that were derived from the unbound fraction of jacalin affinity chromatography and subsequent tert-octylphenoxy poly (oxyethylene) ethanol Triton X-114 (TX-114) partitioning in the diagnosis of human neurocysticercosis (NCC). Immunoassays were designed to detect T. solium-specific IgG antibodies by ELISA and immunoblot. Serum samples were collected from 132 individuals who were categorised as follows: 40 had NCC, 62 presented Taenia spp or other parasitic diseases and 30 were healthy individuals. The jacalin-unbound (J unbound ) fraction presented higher sensitivity and specificity rates than the jacalin-bound fraction and only this fraction was subjected to subsequent TX-114 partitioning, resulting in detergent (DJ unbound ) and aqueous (AJ unbound ) fractions. The ELISA sensitivity and specificity were 85% and 84.8% for J unbound , 92.5% and 93.5% for DJ unbound and 82.5% and 82.6% for AJ unbound . By immunoblot, the DJ unbound fraction showed 100% sensitivity and specificity and only serum samples from patients with NCC recognised the 50-70 kDa T. solium-specific components. We conclude that the DJ unbound fraction can serve as a useful tool for the differential immunodiagnosis of NCC by immunoblot.

The aim of the present study is to investigate genetic polymorphisms in Taenia solium metacestodes from different Brazilian geographical areas and to relate them to antibody recognition in serum samples of neurocysticercosis (NC) patients. Metacestodes were obtained from the Distrito Federal (DF), Bahia, Minas Gerais (MG) and São Paulo (SP) regions of Brazil. Samples of human sera from 49 individuals with NC, 68 individuals with other helminthiasis and 40 healthy volunteers were analysed (157 individuals in total). Antigens were prepared and used in enzyme-linked immunosorbent assay and western blotting assays to detect specific immunoglobulin G antibodies. Genetic distances between metacestode populations were analysed using random amplified polymorphic DNA (RAPD) analysis. Our results show that there was a higher frequency of reactivity in the DF region in the sera from NC patients (p < 0.05), while discrimination between active and inactive NC was seen only in extracts from the MG and SP regions (p < 0.05). Using RAPD, the sample from the DF region presented a greater increase compared to the other regions. A relationship between genetic polymorphisms among T. solium metacestodes from different areas in Brazil and the differences in antibody detection in patients with NC were established.

INTRODUÇÃO: Considerando que antígenos alternativos para o diagnóstico da neurocisticercose (NC) continua sendo um desafio devido ao aumento da dificuldade em se obter parasitas de suínos naturalmente infectados, para a preparação do antígeno homólogo de Taenia solium, o objetivo do presente estudo foi avaliar frações detergente (D) e aquosa (A), do extrato salino de metacestódeo de Taenia saginata para diagnóstico da NC. MÉTODOS: Bovinos, naturalmente infectados com Taenia saginata, procedentes da região do Triângulo Mineiro, Estado de Minas Gerais, Brasil, foram obtidos de frigoríficos e abatidos de acordo com a técnica de inspeção recomendada pelo Serviço de Inspeção Federal. As frações D e A foram obtidas utilizando Triton X-114 (TX-114). Amostras de soro foram obtidas de 40 pacientes com diagnóstico de NC, 45 com diagnóstico de outras doenças parasitárias e 30 de indivíduos aparentemente normais. Níveis de IgG foram avaliados pelos testes ELISA e Imunoblotting. RESULTADOS: A sensibilidade e especificidade do teste ELISA foram 95% e 73,3%, quando utilizado o extrato salino, 95% e 82,6% para fração D, e 65% e 61,3% para a fração A, respectivamente. O ensaio Imunoblotting confirmou os resultados do teste ELISA, sendo a fração D mais eficiente que os outros extratos, observando-se que o componente 70-68kDa se comportou como imunodominante para os pacientes com NC. CONCLUSÕES: Estes resultados demonstraram que a fração D de metacestódeo de Taenia saginata obtida com TX-114 pode ser utilizada como fração antigênica heteróloga pelo Imunoblotting para o diagnóstico sorológico da NC humana, considerando sua habilidade para selecionar antígenos imunodominantes.

INTRODUCTION: Considering that alternative antigens for diagnosing neurocysticercosis continue to be a challenge because of the increasing difficulty in obtaining parasites from naturally infected pigs for preparation of Taenia solium homologous antigen, the aim of the present study was to evaluate the detergent (D) and aqueous (A) fractions from saline extract of Taenia saginata metacestodes for diagnosing neurocysticercosis. METHODS: Taenia saginata was obtained from naturally infected bovines in the Triângulo Mineiro region, State of Minas Gerais, Brazil. The carcasses came from cold storage units and had been slaughtered in accordance with the inspection technique recommended by the Federal Inspection Service. The D and A fractions were obtained by using Triton X-114 (TX-114). Serum samples were obtained from 40 patients with a diagnosis of neurocysticercosis, 45 with other parasitic diseases and 30 from apparently normal individuals. IgG antibody levels were evaluated using the ELISA and immunoblotting assays. RESULTS: The ELISA sensitivity and specificity were 95% and 73.3%, when using saline extract; 95% and 82.6% for the D fraction; and 65% and 61.3% for the A fraction, respectively. The immunoblotting assay confirmed the ELISA results, such that the D fraction was more efficient than the other extracts, and the 70-68kDa component was immunodominant among neurocysticercosis patients. CONCLUSIONS: These results demonstrated that the D fraction from Taenia saginata metacestodes obtained using TX-114 can be used as a heterologous antigenic fraction in the immunoblotting assay for serologically diagnosing human neurocysticercosis, given its ability to select immunodominant antigens.

INTRODUÇÃO: do ponto de vista epidemiológico mais de 120 espécies de triatomíneos (Hemiptera, Reduviidae) são conhecidas. A ocorrência e a positividade de Trypanosoma cruzi em triatomíneos de 16 municípios do Triângulo Mineiro e Alto Paranaíba foram avaliadas de janeiro de 2002 a dezembro de 2004. MÉTODOS: os triatomíneos foram capturados seguindo basicamente as normas clássicas da Fundação Nacional de Saúde. Os exames parasitológicos dos triatomíneos foram conduzidos de acordo com a técnica descrita pelo Ministério da Saúde. Durante o período de estudo, foram capturados 990 exemplares de triatomíneos, sendo que 771 dos capturados estavam em condições de serem examinados. RESULTADOS: cinco espécies foram identificadas: Triatoma sordida, Panstrongylus diasi, Panstrongylus megistus, Panstrongylus geniculatus e Rhodnius neglectus. Triatoma sordida representou 71,5% de todos os triatomíneos capturados, seguido por Panstrongylus megistus (18%), Rhodnius neglectus (9,3%), Panstrongylus diasi (0,8%) e Panstrongylus geniculatus (0,4%). Dos triatomíneos examinados, 2,7% foram positivos para Trypanosoma cruzi. Panstrongylus megistus foi a espécie que apresentou a maior taxa de infecção por Trypanosoma cruzi (8,3%), seguida pelo Rhodnius neglectus (2,9%) e Triatoma sordida (1,4%). CONCLUSÕES: há necessidade de se adequar às novas circunstâncias epidemiológicas com ênfase na vigilância entomológica, uma vez que o potencial de adaptação de espécies secundárias de triatomíneos, em áreas onde a doença de Chagas está controlada, é uma preocupação.

INTRODUCTION: from an epidemiological point of view, more than 120 species of triatomine (Hemiptera, Reduviidae) are known. The occurrence and positivity for Trypanosoma cruzi in triatomines in 16 municipalities of the Triângulo Mineiro and Alto Paranaíba were evaluated from January 2002 to December 2004. METHODS: the triatomines were captured basically according to the classic norms of the National Health Foundation. The parasitological exams of the triatomines were conducted according to the technique described by the Ministry of Health. During the study period, 990 specimens of triatomines were captured and of these, 771 could be examined. RESULTS: five species were identified: Triatoma sordida, Panstrongylus diasi, Panstrongylus megistus, Panstrongylus geniculatus and Rhodnius neglectus. Triatoma sordida represented 71.5% of all the triatomines captured, followed by Panstrongylus megistus (18%), Rhodnius neglectus (9.3%), Panstrongylus diasi (0.8%) and Panstrongylus geniculatus (0.4%). Of the total number of triatomines examined, 2.7% were positive for Trypanosoma cruzi. Panstrongylus megistus was the species that presented the highest rates of infection by Trypanosoma cruzi (8.3%), followed by Rhodnius neglectus (2.9%) and Triatoma sordida (1.4%). CONCLUSIONS: there is a need to adapt to new circumstances in epidemiology, with greater emphasis on entomological surveillance, since the potential for adaptation of secondary species of triatomines exists, especially where Chagas' disease is already under control.

O objetivo deste estudo foi determinar a ocorrência de parasitas e comensais intestinais em crianças de quatro bairros periféricos, localizados nos setores norte, sul, leste e oeste em Uberlândia, Minas Gerais, utilizando os métodos de Baermann modificado por Moraes, e de Lutz. Dos 160 indivíduos estudados, 93 (58,1%, IC: 50,4-65,7) estavam infectados, assim distribuídos: setor norte (72,5%), sul (47,5%), leste (57,5%) e oeste (55%). A positividade por faixa etária foi: 0 - 5 anos (26,9%), 5 - 10 (21,2%) e 10 - 15 anos (10%). As crianças do sexo masculino mostraram 2,7 maior risco de infecção (OR: 2,7, IC: 1052-7001). Os agentes identificados foram: Giardia lamblia (27,5%), Entamoeba coli (20,6%), Ascaris lumbricoides (14,4%), Enterobius vermicularis (8,8%), Hymenolepis nana (7,5%), Hymenolepis diminuta (5%), ancilostomídeos (3,1%), Trichuris trichiura (2,5%), Endolimax nana (2,5%), Entamoeba hartmanni (2,5%), Strongyloides stercoralis (1,3%), Iodamoeba butschlii (1,3%) e Capillaria hepatica (0,6%). A porcentagem de infecção nas crianças foi alta e mostrou a necessidade de implantação de programas de educação profilática na comunidade.

The aim of this study was to determine the occurrence of intestinal parasites and commensals among children in four peripheral districts located in the northern, southern, eastern and western sectors of Uberlândia, Minas Gerais, using the Baermann methods as modified by Moraes and Lutz. Out of 160 individuals studied, 93 (58.1% CI: 50.4-65.7) were infected, distributed among the sectors as follows: northern (72.5%), southern (47.5%), eastern (57.5%) and western (55%). The positive findings according to age groups were: 0-5 years (26.9%), 5-10 years (21.2%) and 10-15 years (10%). Male children presented 2.7 times higher risk of infection than females did (OR: 2.7; CI: 1052-7001). The parasites and commensals identified were: Giardia lamblia (27.5%), Entamoeba coli (20.6%), Ascaris lumbricoides (14.4%), Enterobius vermicularis (8.8%), Hymenolepis nana (7.5%), Hymenolepis diminuta (5%), hookworms (3.1%), Trichuris trichiura (2.5%), Endolimax nana (2.5%), Entamoeba hartmanni (2.5%), Strongyloides stercoralis (1.3%), Iodamoeba butschlii (1.3%) and Capillaria hepatica (0.6%). The infection rate in these children was high and showed the need to implement prophylactic education programs in the community.

The aim of this study was to test if serological distinction between patients with active and inactive neurocysticercosis (NCC), could be accomplished by the recognition of immunodominant peptides in total saline antigenic extract of Taenia solium metacestodes by IgG antibody in cerebrospinal fluid (CSF) and serum paired samples. CSF and serum samples of 10 each, active NCC patients, inactive NCC, and individuals with other neurological disorders, were used to recognize the antigenic peptides by western blot (WB). In the active NCC the 28-32 and 39-42 kDa peptides were more frequently detected in CSF than in sera (p < 0.05). The 47-52, 64-68, and 70 kDa antigens showed high frequencies in both samples from patients with active NCC. All the CSF samples of inactive NCC and other neurological disorder (control) patients tested negative, while serum samples from these last two groups recognized mainly the 80, 86, 95, and 98 kDa bands. This finding eliminates the use of the high molecular weigh bands (> 80 kDa) for diagnosis of NCC. The final conclusions were that the difference between active and inactive NCC may be done with the detection of peptides only in the CSF samples and that the 47-52, 64-68, and 70 kDa bands may be included as specific markers for active NCC when detected in CSF samples by WB using total saline extract of T. solium metacestode.

Paired samples of cerebrospinal fluid (CSF) and serum of 30 patients - 10 with active, 10 with inactive neurocysticercosis (NCC), and 10 control subjects - were evaluated by enzyme-linked immunosorbent assay (ELISA) using two Taenia crassiceps metacestode extracts as antigen in order to detect IgG antibodies. In active NCC, high levels of IgG were detected (p < 0.05). The CSF samples showed 80% (CI 72-88) of reactivity in the saline extract (S) and 90% (CI 84-95) in sodium dodecyl sulphate (SDS) and the serum samples were reactive in 90% (CI 84-95) and 100% (CI 98-100) in the S and SDS antigenic extracts, respectively. The use of the paired samples of CSF and serum in active NCC showed equivalent results suggesting that the serum samples could be used as a screening in those patients whose CSF puncture is counter-indicated.

IgE antibody response in human strongyloidiasis was evaluated by enzyme-linked immunosorbent assay (ELISA) and immunoblotting (IB) using Strongyloides ratti saline extract as heterologous antigen. A total of 50 serum samples of patients who were shedding S. stercoralis larvae in feces (group I, copropositive), 38 of patients with other intestinal parasites (group II), and 38 of subjects with negative results in three parasitologic assays (group III, copronegative) were analyzed. Levels of IgE anti-Strongyloides expressed in ELISA Index (EI) were significantly higher in patients of group I (1.32) than in group II (0.51) and group III (0.81), with positivity rates of 54%, 0%, and 10.5%, respectively. Fifteen S. ratti antigenic components were recognized in IB-IgE by sera of group I, with frequency ranging from 8% to 46%. In group II, only two antigenic bands (101, 81 kDa) were detected in a frequency of 10% and no reactivity was found in group III. Sera with EI values > 1.5 recognized five from 13 specific antigenic bands (70, 63, 61, 44, 7 kDa). It can be concluded that these five antigenic components recognized by IB-IgE using S. ratti antigen might be employed as an additional tool for improving the immunodiagnosis in human strongyloidiasis.