Studies on the Parasitic Helminths of the North Central States. II. Helminths of Voles (Microtus spp.) Preliminary Report

The helminths of North American mouse-like rodents have received little study. Previous work has been based on low numbers of animals examined, and there has been little reference to the ecology involved. The purpose of this paper is to present data resulting from the examination of over 600 voles, with special reference to host-parasite relationships

Parasitological and serological studies on Amoebiasis and other intestinal parasitic infections in Recife and its suburban area, northeast Brazil

Parasitological examinations were carried out during April to August, 1987, with 187 out-patients of the IMIP hospital, located in the center of Recife City, and 464 inhabitants of several villages around Cabo City, 50 Km southeast of Recife, Pernambuco, Brazil. Approximately 71% of the IMIP patients and 92% of the Cabo inhabitants were infected with at least one species of intestinal parasite. There was minimum difference in the prevalence rate of Trichuris trichiura between two areas, whereas the prevalence rates of Ascaris lumbricoides, hookworms, Strongyloides stercoralis, Schistosoma mansoni and Entamoeba histolytica were higher in the inhabitants of the Cabo City area. Only Giardia lamblia was more prevalent in the out-patients of IMIP hospital. Test tube cultivation revealed that the prevalence rate of Necator americanus in both areas was much higher than that of Ancylostoma duodenale , and also that the prevalence rate of S. stercoralis of the IMIP patients and Cabo inhabitants were 4.5% and 9.6%, respectively. Six hundred and fifteen sera were serologically examined for amoebiasis by the gel diffusion precipitation test (GDP) and enzyme linked immunosorbent assay (ELISA) using the antigen prepared from axenically cultured trophozoite of E. histolytica (strain HM-ITMSS). No positive reaction was observed in all of the sera as examined by GDP, while 32 out of 615 sera were positive on ELISA.

Parasitological and serological studies on amoebiasis and other intestinal parasitic infections in the rural sector around Recife, Northeast Brazil

Parasitological examinations were carried out during July to December, 1989, on 485 inhabitants of four villages in São Lourenço da Mata, 25 km northwest of Recife, Pernambuco, Brazil. Approximately 99.6% of the inhabitants were infected with at least one species of intestinal parasites. A high prevalence of Schistosoma mansoni (82.1%), hookworm (80.2%) Trichuris trichiura (69.9%), Ascaris lumbricoides (61.9%) and Entamoeba coli (36.7%) infections were demonstrated. Test tube cultivation revealed that the most common species of hookworm in this region was Necator americanus (88.4%), and also that the prevalence of Strongyloides stercoralis was 5.8%. Three hundred and thirty-four sera were serologically examined for amoebiasis by the gel diffusion precipitation test (GDP) and enzyme-linked immunosorbent assay (ELISA). No positive reaction was observed in all sera as examined by GDP, while 24 sera were positive by ELISA.

Animal helminths in human archaeological remains: a review of zoonoses in the past

The authors present a review of records of intestinal parasitic helminths from animals in human archaeological remains, reported since the emergence of paleopathological studies. The objective was to relate paleoparasitological findings to geographic, biotic, and abiotic factors from the environment in which the prehistoric populations lived, and understand some aspects related to the process of human dispersion and biological and cultural evolution. Modification of eating habits and the incorporation of new cultural practices are analyzed from the perspective of zoonoses from prehistory to the present day, especially in Brazilian indigenous populations. Three tables identifying the helminths, their natural hosts, dates, and sites of archaeological findings complete this review. In conclusion, various zoonoses known today have occurred since antiquity, and these data, combined with studies on the emergence and reemergence of diseases, could make possible to compose scenarios for the future.

Helminths parasites of freshwater fishes from Pirassununga, SP, Brazil

Twelve species of parasitic helminths, seven trematodes, four nematodes and one acanthocephalan are reported from various hosts. Creptotrema lynchi, a parasite from Bufo marinus in Colombia, is described for the first time in fish and from Brazil, parasitizing two different species. A list of the host species, measurements and figures of most parasites are included with particular reference to the tegument of Bellumcorpus major recovered from a new host. The genus Zonocotyloides Padilha, 1978 is considered a synonym of Zonocotyle and the new combination: Zonocotyle haroltravassosi is proposed to the species Zonocotyloides haroltravassosi Padilha, 1978. The nematodes Cucullanus pinnai and Procamallanus (Spirocamallanus) inopinatus and the trematode Pararhipidocotyle jeffersoni are reported in new hosts. The description of the acanthocephalan Neoechinorhynchus curemais (new locality record) is supplemented. Other parasites recovered include the nematodes Travnema travnema (new locality record), Rondonia rondoni and the digenetic trematodes Cladocystis intestinalis, Pseudosellacotyla lutzi (new locality record), Teratotrema sp. and Zonocotyle bicaecata.

MicroRNAs in Parasitic Helminthiases: Current Status and Future Perspectives

MicroRNAs (miRNAs) play a variety of roles in diverse biological processes at the post-transcriptional regulatory level. Although numerous miRNAs have been identified in parasitic helminths, we still know little about their biological functions. As molecular signatures that can be stably detectable in serum and plasma, worm-derived miRNAs have shown promise as markers for the early detection of particular helminth infections. In addition, host miRNAs are dysregulated during the development of pathology associated with helminthiases and show potential as therapeutic intervention targets. This review discusses the possible biological roles of helminth miRNAs, the prediction of their specific targets, their application in diagnosis and anti-pathology therapy interventions, and the potential functions of miRNAs in extracellular vesicle cargo, such as exosomes, in helminth-host interplay.

Helminthological records of six-banded Armadillos Euphractus sexcinctus (Linnaeus, 1758) from the Brazilian semi-arid region, Patos county, Paraiba state, including new morphological data on Trichohelix tuberculata (Parona and Stossich, 1901) Ortlepp, 1922 and proposal of Hadrostrongylus ransomi nov comb.

This work aimed to evaluate the gastrointestinal helminthfauna composition of six-banded armadillos from the Brazilian semi-arid region. Gastrointestinal contents of six road-killed adult animals from Patos County, Paraiba State, were analyzed. Six species of nematodes, comprising five genera and four families, were recovered from the analyzed animals. New morphological data on Trichohelix tuberculata is given, along with a new taxonomical proposal for Hadrostrongylus ransomi (Travassos, 1935) n. comb. This is the first record for parasitic helminths in this host from the Brazilian semi-arid.

Sistemática e indicadores de infecção por helmintos parasitos de jaós (Crypturellus undulatus), no Estado do Mato Grosso do Sul (Pantanal de Paiaguás), e de codornas (Nothura maculosa) e nambuzinhos (Crypturellus parvirostris) no Estado de São Paulo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudos parasitológicos em cães domésticos errantes e carnívoros selvagens generalistas no Parque Nacional do Iguaçu, Foz do Iguaçu

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Regulatory T cell-mediated suppression of Th9 cell development and effector function

T helper (Th) 9 cells are an important subpopulation of the CD4+ T helper cells. Due to their ability to secrete Interleukin-(IL-)9, Th9 cells essentially contribute to the expulsion of parasitic helminths from the intestinal tract but they play also an immunopathological role in the course of asthma. Recently, a beneficial function of Th9 cells in anti-tumor immune responses was published. In a murine melanoma tumor model Th9 cells were shown to enhance the anti-melanoma immune response via the recruitment of CD8+ T cells, dendritic cells and mast cells. In contrast to Th9 effector cells regulatory T cells (Tregs) are able to control an immune response with the aid of different suppressive mechanisms. Based on their ability to suppress an immune response Tregs are believed to be beneficial in asthma by diminishing excessive allergic reactions. However, concerning cancer they can have a detrimental function because Tregs inhibit an effective anti-tumor immune reaction. Thus, the analysis of Th9 suppression by Tregs is of central importance concerning the development of therapeutic strategies for the treatment of cancer and allergic diseases and was therefore the main objective of this PhD thesis.rnIn general it could be demonstrated that the development of Th9 cells can be inhibited by Tregs in vitro. The production of the lineage-specific cytokine IL-9 by developing Th9 cells was completely suppressed at a Treg/Th9 ratio of 1:1 on the transcriptional (qRT-PCR) as well as on the translational level (ELISA). In contrast, the expression of IRF4 that was found to strongly promote Th9 development was not reduced in the presence of Tregs, suggesting that IRF4 requires additional transcription factors to induce the differentiation of Th9 cells. In order to identify such factors, which regulate Th9 development and therefore represent potential targets for Treg-mediated suppressive mechanisms, a transcriptome analysis using “next-generation sequencing” was performed. The expression of some genes which were found to be up- or downregulated in Th9 cells in the presence of Tregs was validated with qRT-PCR. Time limitations prevented a detailed functional analysis of these candidate genes. Nevertheless, the analysis of the suppressive mechanisms revealed that Tregs probably suppress Th9 cells via the increase of the intracellular cAMP concentration. In contrast, IL-9 production by differentiated Th9 cells was only marginally affected by Tregs in vitro and in vivo analysis (asthma, melanoma model). Hence, Tregs represent very effective inhibitors of Th9 development whereas they have only a minimal suppressive influence on differentiated Th9 cells.rn

Suppression by {\it Trypanosoma brucei\/} of anaphylaxis-mediated ion transport in the small intestine of rats

Most tissue-invasive parasitic helminths prime for type 1 hypersensitivity or anaphylaxis during some phase of their life cycles. A prototype in this regard is the nematode Trichinella spiralis. Blood protozoa capable of tissue invasion, such as Trypanosoma brucei, might also be expected to prime for the expression of anaphylaxis. However, this response is usually absent in protozoal infections. The hypothesis tested was that failure of hosts infected with T.brucei to express anaphylaxis is related to this parasite's ability to selectively down-regulate immunoglobulin E (IgE) production, and not to an innate lack of allergenicity on the part of T.brucei-derived antigens. This hypothesis was tested by studying in the intestine of rats, antigen-induced Cl$\sp-$ secretion, which results from a local anaphylactic response mediated by IgE and mucosal mast cells. The Cl$\sp-$ secretory response can be primed either by infection with T.spiralis or by the parenteral administration of antigen. Anaphylaxis-induced Cl$\sp-$ secretion is expressed in vitro, and can be quantified electrophysiologically, as a change in transmural short-circuit current when sensitized intestine is mounted in Ussing chambers and challenged with the sensitizing antigen.^ Rats injected parenterally with trypanosome antigen elicited intestinal anaphylaxis in response to antigenic challenge. In contrast, the intestine of rats infected with T.brucei failed to respond to challenge with trypanosome antigen. Infection with T.brucei also suppressed antigen-induced Cl$\sp-$ secretion in rats sensitized and challenged with various antigens, including T.spiralis antigen. However, T.brucei infection did not inhibit the anaphylactic response in rats concomitantly infected with T.spiralis. Relative to the anaphylactic mediators, T.brucei infection blocked production of IgE in rats parenterally injected with antigen but not in T.spiralis-infected hosts. Also, the mucosal mastocytosis normally associated with trichinosis was unaffected by the trypanosome infection. These results support the conclusion that the failure to express anaphylaxis-mediated Cl$\sp-$ secretion in T.brucei infected rats, is due to this protozoan's ability to inhibit IgE production and not to the lack of allergenicity of trypanosome antigens. ^

Functional expression of a novel Kunitz type protease inhibitor from the human blood fluke Schistosoma mansoni

BACKGROUND: Schistosomes are able to survive for prolonged periods in the blood system, despite continuous contact with coagulatory factors and mediators of the host immune system. Protease inhibitors likely play a critical role in host immune modulation thereby promoting parasite survival in this extremely hostile environment. Even though Kunitz type serine protease inhibitors have been shown to play important physiological functions in a range of organisms these proteins are less well characterised in parasitic helminths.

METHODS: We have cloned one gene sequence from S. mansoni, Smp_147730 (SmKI-1) which is coded for single domain Kunitz type protease inhibitor, E. coli-expressed and purified. Immunolocalisation and western blotting was carried out using affinity purified polyclonal anti-SmKI-1 murine antibodies to determine SmKI-1 expression in the parasite. Protease inhibitor assays and coagulation assays were performed to evaluate the functional roles of SmKI-1.

RESULTS: SmKI-1 is localised in the tegument of adult worms and the sub-shell region of eggs. Furthermore, this Kunitz protein is secreted into the host in the ES products of the adult worm. Recombinant SmKI-1 inhibited mammalian trypsin, chymotrypsin, neutrophil elastase, FXa and plasma kallikrein with IC50 values of 35 nM, 61 nM, 56 nM, 142 nM and 112 nM, respectively. However, no inhibition was detected for pancreatic elastase or cathepsin G. SmKI-1 (4 μM) delayed blood clot formation, reflected in an approximately three fold increase in activated partial thromboplastin time and prothrombin time.

CONCLUSIONS: We have functionally characterised the first Kunitz type protease inhibitor (SmKI-1) from S. mansoni and show that it has anti-inflammatory and anti-coagulant properties. SmKI-1 is one of a number of putative Kunitz proteins in schistosomes that have presumably evolved as an adaptation to protect these parasites from the defence mechanisms of their mammalian hosts. As such they may represent novel vaccine candidates and/or drug targets for schistosomiasis control.

Characterisation of a secretory serine protease inhibitor (SjB6) from Schistosoma japonicum

BACKGROUND: Proteins belonging to the serine protease inhibitor (serpin) superfamily play essential physiological roles in many organisms. In pathogens, serpins are thought to have evolved specifically to limit host immune responses by interfering with the host immune-stimulatory signals. Serpins are less well characterised in parasitic helminths, although some are thought to be involved in mechanisms associated with host immune modulation. In this study, we cloned and partially characterised a secretory serpin from Schistosoma japonicum termed SjB6, these findings provide the basis for possible functional roles.

METHODS: SjB6 gene was identified through database mining of our previously published microarray data, cloned and detailed sequence and structural analysis and comparative modelling carried out using various bioinformatics and proteomics tools. Gene transcriptional profiling was determined by real-time PCR and the expression of native protein determined by immunoblotting. An immunological profile of the recombinant protein produced in insect cells was determined by ELISA.

RESULTS: SjB6 contains an open reading frame of 1160 base pairs that encodes a protein of 387 amino acid residues. Detailed sequence analysis, comparative modelling and structural-based alignment revealed that SjB6 contains the essential structural motifs and consensus secondary structures typical of inhibitory serpins. The presence of an N-terminal signal sequence indicated that SjB6 is a secretory protein. Real-time data indicated that SjB6 is expressed exclusively in the intra-mammalian stage of the parasite life cycle with its highest expression levels in the egg stage (p < 0.0001). The native protein is approximately 60 kDa in size and recombinant SjB6 (rSjB6) was recognised strongly by sera from rats experimentally infected with S. japonicum.

CONCLUSIONS: The significantly high expression of SjB6 in schistosome eggs, when compared to other life cycle stages, suggests a possible association with disease pathology, while the strong reactivity of sera from experimentally infected rats against rSjB6 suggests that native SjB6 is released into host tissue and induces an immune response. This study presents a comprehensive demonstration of sequence and structural-based analysis of a secretory serpin from a trematode and suggests SjB6 may be associated with important functional roles in S. japonicum, particularly in parasite modulation of the host microenvironment.

Functional characterization of SjB10, an intracellular serpin from Schistosoma japonicum

Serine protease inhibitors (serpin) play essential roles in many organisms. Mammalian serpins regulate the blood coagulation, fibrinolysis, inflammation and complement activation pathways. In parasitic helminths, serpins are less well characterized, but may also be involved in evasion of the host immune response. In this study, a Schistosoma japonicum serpin (SjB10), containing a 1212 bp open reading frame (ORF), was cloned, expressed and functionally characterized. Sequence analysis, comparative modelling and structural-based alignment revealed that SjB10 contains the essential structural motifs and consensus secondary structures of inhibitory serpins. Transcriptional profiling demonstrated that SjB10 is expressed in adult males, schistosomula and eggs but particularly in the cercariae, suggesting a possible role in cercarial penetration of mammalian host skin. Recombinant SjB10 (rSjB10) inhibited pancreatic elastase (PE) in a dose-dependent manner. rSjB10 was recognized strongly by experimentally infected rat sera indicating that native SjB10 is released into host tissue and induces an immune response. By immunochemistry, SjB10 localized in the S. japonicum adult foregut and extra-embryonic layer of the egg. This study provides a comprehensive demonstration of sequence and structural-based analysis of a functional S. japonicum serpin. Furthermore, our findings suggest that SjB10 may be associated with important functional roles in S. japonicum particularly in host-parasite interactions.

Prevalence of intestinal parasitic infection in five farms in Holambra, São Paulo, Brazil

A parasitological survey was carried out on 222 inhabitants of five farms in Holambra, located 30 km north of Campinas, São Paulo, Brazil, on October 1992. Approximately 70% of the inhabitants were found to be infected with at least one species of intestinal parasite. The positive rates of 6 helminths and 7 protozoan species detected are as follows: 5.4% Ascaris lumbricoides; 8.6% Trichuris trichiura; 19.8% Necator americanus; 10.4% Strongyloides stercoralis; 14% Enterobius vermicularis; 0.9% Hymenolepis nana; 3.2% Entamoeba histolytica; 2.7% E. hartmanni; 9.9% E. coli; 14.0% Endolimax nana; 2.3% Iodamoeba butschlii; 10.4% Giardia lamblia; 37.8% Blastocystis hominis. The positive rates of helminth infection were generaly higher in the younger-group under 16 years-old than those in the elder group aged 16 or more, whereas the infection rates of protozoan species were higher in the elder group. The infection rate of Strongyloides was found to be 10.4% by a newly developed sensitive method (an agarplate culture methods).