Antimicrobial and anthelmintic effects of copper nanoparticles against Koi carp parasites and their toxicity.

This study investigated the in vitro antimicrobial and anthelmintic effect of copper nanoparticles (CuNPs) against the bacterium Aeromonas hydrophila, the monogeneans Dactylogyrus minutus, Dactylogyrus extensus, Gyrodactylus cyprini, and the cestode Schyzocotyle acheilognathi, as well as their toxicity to Cyprinus carpio Koi. In the antimicrobial in vitro test, the inhibition zone method and minimum inhibitory concentration (MIC) were performed. In order to determine the time and efficacy of monogenean parasite mortality, the parasites were exposed to CuNP concentrations of 20, 50, 100, 150, 200, and 300 mg L-1, and a control group with tank water and one with copper sulphate pentahydrate (CuSO4.5H2O) at a concentration of 0.3 mg L-1, performed in triplicate. The parasites were observed every 10 min for 300 min, and mortality was recorded. For the cestodes, parasites were immersed in CuNP concentrations of 50, 100, 150, and 300 mg L-1. At the end of the in vitro tests, the anthelmintic efficacy of each treatment was calculated. To assess the tolerance and toxicity in fish, they were exposed to CuNP concentrations of 0.6, 1.25, 2.5, 5, 10, 20, and 50 mg L-1 for 12 h. The MIC demonstrated that CuNPs effectively inhibited the growth of A. hydrophila up to a dilution of 12,500 mg L-1 and showed an inhibition zone of 14.0 ± 1.6 mm for CuNPs. The results of anthelmintic activity showed a dose-dependent effect of concentration for both groups of parasites, with the most effective concentration being 300 mg L-1 in 120 min. In the toxicity test, the carps showed tolerance to lower concentrations. The study indicated that CuNPs were effective against the studied pathogens. However, it proved to be toxic to fish at high concentrations. The use of low concentrations is recommended still requires further investigation.

Endogenous innate sensor NLRP3 is a key component in peritoneal macrophage dynamics required for cestode establishment.

The NLRP3 receptor can assemble inflammasome platforms to trigger inflammatory responses; however, accumulating evidence suggests that it can also display anti-inflammatory properties. Here, we explored the role of nucleotide-binding oligomerization domain pyrin-containing protein 3 (NLRP3) in Taenia crassiceps experimental infection, which requires immune polarization into a Th2-type profile and peritoneal influx of suppressive macrophages for successful colonization. NLRP3 deficient mice (NLRP3-/-) were highly resistant against T. crassiceps, relative to wild-type (WT) mice. Resistance in NLRP3-/- mice was associated with a diminished IL-4 output, high levels of IL-15, growth factor for both innate and adaptive lymphocytes, and a dramatic decrease in peritoneum-infiltrating suppressive macrophages. Also, a transcriptional analysis on bone marrow-derived macrophages exposed to Taenia-secreted antigens and IL-4 revealed that NLRP3-/- macrophages express reduced transcripts of relm-α and PD-1 ligands, markers of alternative activation and suppressive ability, respectively. Finally, we found that the resistance displayed by NLRP3-/- mice is transferred through intestinal microbiota exchange, since WT mice co-housed with NLRP3-/- mice were significantly more resistant than WT animals preserving their native microbiota. Altogether, these data demonstrate that NLRP3 is a component of innate immunity required for T. crassiceps to establish, most likely contributing to macrophage recruitment, and controlling lymphocyte-stimulating cytokines such as IL-15.

Biochemical characterization and gene structure analysis of the 24-kDa glutathione transferase sigma from Taenia solium.

Taenia solium can cause human taeniasis and/or cysticercosis. The latter can in some instances cause human neurocysticercosis which is considered a priority in disease-control strategies and the prevention of mental health problems. Glutathione transferases are crucial for the establishment and long-term survival of T. solium; therefore, we structurally analyzed the 24-kDa glutathione transferase gene (Ts24gst) of T. solium and biochemically characterized its product. The gene promoter showed potential binding sites for transcription factors and xenobiotic regulatory elements. The gene consists of a transcription start site, four exons split by three introns, and a polyadenylation site. The gene architecture is conserved in cestodes. Recombinant Ts24GST (rTs24GST) was active and dimeric. Anti-rTs24GST serum showed slight cross-reactivity with human sigma-class GST. A 3D model of Ts24GST enabled identification of putative residues involved in interactions of the G-site with GSH and of the H-site with CDNB and prostaglandin D2. Furthermore, rTs24GST showed optimal activity at 45 °C and pH 9, as well as high structural stability in a wide range of temperatures and pHs. These results contribute to the better understanding of this parasite and the efforts directed to fight taeniasis/cysticercosis.

First known case of human bertiellosis in a child in Paraná, Brazil / Primeiro caso conhecido de bertielose humana em uma criança no Paraná, Brasil

ABSTRACT Objective: To describe the first known case of human Bertiellosis in Paraná (Brazil). Case description: A 6-year-old male residing in the Brazilian state of Paraná was suffering from intermittent nonspecific abdominal pain and abdominal distension, associated with expulsion of live tapeworms in his feces for 7 months. He had a history of interaction with monkeys on an island. His first feces analysis was inconclusive, with an initial hypothesis of an atypical Taenia. However, after additional research, the parasitologist identified pregnant proglottids of Bertiella sp. The patient was initially treated with an unknown dosage of albendazole and nitazoxanide, as it was believed he had been infected with Taenia sp. Since the symptoms persisted, praziquantel 10 mg/kg was prescribed without further proglottids elimination. Comments: Human Bertiellosis is a rare zoonosis, with less than one hundred cases reported. However, it is a cause of chronic abdominal pain and should be kept as a differential diagnosis, especially in cases reporting recurrent tapeworm expulsion in feces and refractory treatment with albendazole.

RESUMO Objetivo: Descrever o primeiro caso conhecido de bertielose humana no Paraná, Brasil. Descrição do caso: Criança de seis anos do sexo masculino, residente no Paraná, Brasil, apresentava dor abdominal inespecífica intermitente e distensão abdominal, associadas à expulsão de helmintos vivos em suas fezes havia sete meses. Tinha um histórico de interação com macacos em uma ilha. Sua primeira análise de fezes foi inconclusiva, com hipótese inicial de uma Taenia atípica. No entanto, após pesquisas adicionais, o parasitologista identificou proglótides gravídicas de Bertiella sp. O paciente foi inicialmente tratado com uma dosagem desconhecida de albendazol e nitazoxanida, pois se acreditava que havia sido infectado por Taenia sp. Diante da persistência dos sintomas, foi prescrito praziquantel 10 mg/kg, sem mais eliminação de proglótides. Comentários: A bertielose humana é uma zoonose rara, com menos de cem casos relatados. No entanto, é uma causa de dor abdominal crônica e deve ser mantida como diagnóstico diferencial, principalmente nos casos que relatam expulsão recorrente de helmintos nas fezes e que são refratários ao tratamento com albendazol.

Stem cell proliferation and differentiation during larval metamorphosis of the model tapeworm Hymenolepis microstoma.

Background: Tapeworm larvae cause important diseases in humans and domestic animals. During infection, the first larval stage undergoes a metamorphosis where tissues are formed de novo from a population of stem cells called germinative cells. This process is difficult to study for human pathogens, as these larvae are infectious and difficult to obtain in the laboratory. Methods: In this work, we analyzed cell proliferation and differentiation during larval metamorphosis in the model tapeworm Hymenolepis microstoma, by in vivo labelling of proliferating cells with the thymidine analogue 5-ethynyl-2'-deoxyuridine (EdU), tracing their differentiation with a suite of specific molecular markers for different cell types. Results: Proliferating cells are very abundant and fast-cycling during early metamorphosis: the total number of cells duplicates every ten hours, and the length of G2 is only 75 minutes. New tegumental, muscle and nerve cells differentiate from this pool of proliferating germinative cells, and these processes are very fast, as differentiation markers for neurons and muscle cells appear within 24 hours after exiting the cell cycle, and fusion of new cells to the tegumental syncytium can be detected after only 4 hours. Tegumental and muscle cells appear from early stages of metamorphosis (24 to 48 hours post-infection); in contrast, most markers for differentiating neurons appear later, and the detection of synapsin and neuropeptides correlates with scolex retraction. Finally, we identified populations of proliferating cells that express conserved genes associated with neuronal progenitors and precursors, suggesting the existence of tissue-specific lineages among germinative cells. Discussion: These results provide for the first time a comprehensive view of the development of new tissues during tapeworm larval metamorphosis, providing a framework for similar studies in human and veterinary pathogens.

Cestodes in the genomic era.

The first cestode genomes were obtained by an international consortium led by the Wellcome Sanger Institute that included representative institutions from countries where the sequenced parasites have been studied for decades, in part because they are etiological agents of endemic diseases (Argentina, Uruguay, Mexico, Canada, UK, Germany, Switzerland, Ireland, USA, Japan, and China). After this, several complete genomes were obtained reaching 16 species to date. Cestode genomes have smaller relative size compared to other animals including free-living flatworms. Moreover, the features genome size and repeat content seem to differ in the two analyzed orders. Cyclophyllidean species have smaller genomes and with fewer repetitive content than Diphyllobothriidean species. On average, cestode genomes have 13,753 genes with 6 exons per gene and 41% GC content. More than 5,000 shared cestode proteins were accurately annotated by the integration of gene predictions and transcriptome evidence being more than 40% of these proteins of unknown function. Several gene losses and reduction of gene families were found and could be related to the extreme parasitic lifestyle of these species. The application of cutting-edge sequencing technology allowed the characterization of the terminal sequences of chromosomes that possess unique characteristics. Here, we review the current status of knowledge of complete cestode genomes and place it within a comparative genomics perspective. Multidisciplinary work together with the implementation of new technologies will provide valuable information that can certainly improve our chances to finally eradicate or at least control diseases caused by cestodes.

Inhibitors of protein kinases A and C impair the motility of oncospheres of the model tapeworm Hymenolepis microstoma.

The oncosphere larvae of tapeworms cyclically extend and retract their hooks during the penetration of the intestine of their intermediate hosts. The mechanisms regulating these movements are essentially unknown, in part due to the biohazardous nature of oncospheres from human pathogens. In this work, we standardized a method for the analysis of motility of hatched oncospheres (hexacanths) of the model tapeworm Hymenolepis microstoma. We used this assay to explore the relevance of protein kinases C (PKC) and A (PKA) in these processes. Pharmacological inhibition of the PKC pathway resulted in impaired larval motility. On the other hand, the PKA inhibitor H-89 potently blocked larval motility, as well as the motility of other life stages, although other inhibitors of the PKA pathway were not effective. This work represents the first study of the mechanisms that regulate the motility of oncospheres, and provides a path for further exploration.

Intestinal parasites and risk factors in dogs and cats from Rio de Janeiro, Brazil.

The urban populations of pets, mainly dogs and cats, have been growing in recent years and, consequently, human-animal relationships have become increasingly closer. However, pets are vulnerable to infection by various parasites, as well are their owners due to the zoonotic potential of these agents. This study aimed to assess the frequency and risk factors of intestinal parasites in dogs and cats attended at the Municipal Institute of Veterinary Medicine Jorge Vaitsman, Rio de Janeiro, Brazil, as well as georeferencing the parasitized animals. A total of 608 animals (400 dogs and 208 cats) were enrolled from August 2017 to November 2018. Fecal samples were obtained from the animal's rectum during clinical examination. In addition, the owners of the enrolled dogs and cats were asked to complete an epidemiological questionnaire with questions about the animals' general information, lifestyle, and handling. Fecal samples were subjected to sedimentation and centrifugal-flotation in sucrose solution techniques. The frequencies of intestinal parasites total in dogs and cats were 11.3% and 24.5%, respectively, with hookworms being the most detected parasites in dogs (8.3%) and Dipylidium caninum in cats (12.5%). Sex was the only variable that showed statistical differences in the canine population males being more often infected than female (p < 0.05), while street access was associated with parasitic infections in cats (p < 0.05). The results obtained in this study demonstrate the need to control parasitic infections in domiciled dogs and cats in different municipalities in the metropolitan region of the state of Rio de Janeiro, including residents in the northern, western and central areas.

Surto de endoparasitose em galinhas caipiras (Gallus gallus domesticus) na Bahia, Brasil / Outbreak of endoparasitosis in free-range chickens (Gallus gallus domesticus) in Bahia, Brazil

Background: Free-range chickens are quite common in Brazil. In this alternative rearing system, the animals are rustic and raised in an extensive system. Free access to "bare soil" results in the increased occurrence of intestinal parasites since larvae and / or eggs of helminths and protozoa oocysts find favorable conditions for their survival and dissemination in the soil. Although the occurrence and importance of parasitic infections in free-range chickens is well known, the objective of this study is to report an outbreak of endoparasites in free-range chickens in the municipality of Barra - BA, in view of bird susceptibility associated with scarcity of studies in western Bahia. Cases: The chickens were kept free, in a bare soil yard in a household at the urban perimeter of the municipality of Barra - BA. Feeding consisted of whole corn grains, thrown directly in the soil. The drinking fountains were dirty and the animals had no history of vaccination or deworming. Symptoms Anorexia, difficulty in eating and in locomotion, presence of seromucous secretion in the oral cavity, emaciation and diarrhea were all observed symptoms. One of the birds presented excessive vocalization, drowsiness and flaccid paralysis of the neck. Necropsy was performed on 3 chickens: 2 females (cases 1 and 2) and 1 male (case 3). Macroscopic analysis revealed the presence of seromucous secretion in the upper respiratory tract of all animals. Specimens of Ascaridia galli were observed in cases 1 and 2, Heterakis gallinarum in cases 2 and 3, Raillietina sp. in cases 2 and 3 and Davainea proglottina in case 1. Microscopically, the animals had an inflammatory infiltrate in the liver and intestines. Some animals presented necrosis of the tracheal epithelial cells, as well as of the epithelial cells present at the apex of the villi. No significant results were found in the coproparasitological exam. Discussion: The diagnosis of endoparasitosis in this outbreak was based on epidemiological, clinical and pathological findings. The prevalence of intestinal parasitosis in free-range chickens is linked to factors such as age, high animal density, absence of sanitary hygienic measures, as well as environmental temperature and humidity. The appearance of injuries in the intestinal mucosa is influenced by characteristics such as parasitic load, concomitant infections, age and the host's immune status. During necropsy of the birds were found 2 helminths of the Nematoda class (Ascaridia galli and Heterakis gallinarum) and 2 of the Cestoda class (Davainea proglottina and Raillietina sp.). A. galli, seen in 2 cases, is considered low pathogenicity for adult chickens, however young birds are susceptible and can die due to intestinal obstruction and hemorrhages. H. gallinarum is responsible for causing typhlitis, with diarrhea and weight loss, this helminth was found in 2 animals in the present study, however only 1 had changes in the digestive tract. Davainea proglotina and Raillietina spp. might cause, respectively, severe hemorrhagic enteritis and nodule formation in the small intestine mucosa. In Brazil, even though it is notable that intestinal parasitism is one of the key problems in alternative poultry farming, there are few studies that evaluate the presence of endoparasites in chickens raised in alternative production systems, with animals being more frequently exposed to nematodes and cestodes. The multiparasitism observed in this study probably stems from flaws in the rearing system, mainly related to sanitary hygiene management. Therefore, the reduction in the occurrence of these helminths is closely related to the performance of basic prophylactic measures, such as offering good quality food and water in clean containers, separating lots by age, performing sanitary emptiness and deworming.(AU)

Insights from new cestodes of the crocodile shark, Pseudocarcharias kamoharai (Lamniformes: Pseudocarchariidae), prompt expansion of Scyphyophyllidum and formal synonymization of seven phyllobothriidean genera - at last!

Three new cestode species are described from the crocodile shark (Pseudocarcharias kamoharai) in Ecuador. All three were examined with light and scanning electron microscopy. The unique combination of morphological features in one of the new species prompted formal investigation of the non-monophyly of Paraorygmatobothrium relative to the morphologically similar genera Doliobothrium, Guidus, Marsupiobothrium, Nandocestus, Orectolobicestus, Ruhnkecestus and Scyphophyllidium. Sequence data generated for part of the 28S rDNA gene were subjected to maximum likelihood (ML) analysis. The resulting tree led to the synonymization of six of these seven genera with Scyphophyllidium, and transfer of their species to the latter genus. With the new species, the number of described members of Scyphophyllidium is now 45. The diagnosis of Scyphophyllidium is revised to accommodate these species. In addition, to expedite future descriptions, eight categories of Scyphophyllidium species are circumscribed, based largely on bothridial features. Scyphophyllidium timvickiorum n. sp. is a category 1 species. Beyond being the smallest category 1 species, it bears, rather than lacks, apical suckers and lacks, rather than bears, strobilar scutes. The two other new species are members of Clistobothrium. Clistobothrium amyae n. sp. differs from its congeners in bothridial shape, elongate cephalic peduncle and tiny size. Clistobothrium gabywalterorum n. sp. differs from the two of its congeners that also possess foliose bothridia in overall size and testis number. Despite their substantial morphological differences, the ML tree indicates they are sister taxa. Both are unique among their congeners in possessing cephalic peduncle spinitriches. The diagnosis of Clistobothrium is revised accordingly.

Dipylidiasis in children, a generally misdiagnosed cestodiasis. First case reported in Venezuela / Dipylidiasis en niños, una cestodiasis generalmente mal diagnosticada. Primer caso reportado en Venezuela

The first case report of human dipylidiasis in Venezuela is presented, including the diagnosis and treatment of a two-year-old child's infection. The diagnosis was parasitologically confirmed, the child was treated with praziquantel and the animal reservoir and its fleas were identified

Se presenta el primer caso de dipylidiasis humana en Venezuela, incluyendo el diagnóstico y el tratamiento de la infección de un niño de dos años. El diagnóstico fue confirmado parasitológicamente, se trató al niño con praziquantel y fueron identificados el reservorio animal y sus pulgas

Host Switching of Zoonotic Broad Fish Tapeworm (Dibothriocephalus latus) to Salmonids, Patagonia.

Diphyllobothriosis is a reemerging zoonotic disease because of global trade and increased popularity of eating raw fish. We present molecular evidence of host switching of a human-infecting broad fish tapeworm, Dibothriocephalus latus, and use of salmonids as intermediate or paratenic hosts and thus a source of human infection in South America.

Divergent Axin and GSK-3 paralogs in the beta-catenin destruction complexes of tapeworms.

The Wnt/beta-catenin pathway has many key roles in the development of animals, including a conserved and central role in the specification of the primary (antero-posterior) body axis. The posterior expression of Wnt ligands and the anterior expression of secreted Wnt inhibitors are known to be conserved during the larval metamorphosis of tapeworms. However, their downstream signaling components for Wnt/beta-catenin signaling have not been characterized. In this work, we have studied the core components of the beta-catenin destruction complex of the human pathogen Echinococcus multilocularis, the causative agent of alveolar echinococcosis. We focused on two Axin paralogs that are conserved in tapeworms and other flatworm parasites. Despite their divergent sequences, both Axins could robustly interact with one E. multilocularis beta-catenin paralog and limited its accumulation in a heterologous mammalian expression system. Similarly to what has been described in planarians (free-living flatworms), other beta-catenin paralogs showed limited or no interaction with either Axin and are unlikely to function as effectors in Wnt signaling. Additionally, both Axins interacted with three divergent GSK-3 paralogs that are conserved in free-living and parasitic flatworms. Axin paralogs have highly segregated expression patterns along the antero-posterior axis in the tapeworms E. multilocularis and Hymenolepis microstoma, indicating that different beta-catenin destruction complexes may operate in different regions during their larval metamorphosis.

Histone deacetylase enzymes as potential drug targets of Neglected Tropical Diseases caused by cestodes.

Cestode parasites cause neglected diseases, such as echinococcosis and cysticercosis, which represent a significant problem in human and animal health. Benzimidazoles and praziquantel are the only available drugs for chemotherapy and it is therefore important to identify new alternative drugs against cestode parasites. Histone deacetylases (HDACs) are validated drug targets for the treatment of cancer and other diseases, including neglected diseases. However, knowledge of HDACs in cestodes is very scarce. In this work, we investigated cestode HDACs as potential drug targets to develop new therapies against neglected diseases caused by cestodes. Here we showed the full repertoire of HDAC coding genes in several members of the class Cestoda. Between 6 and 7 zinc-dependent HDAC coding genes were identified in the genomes of species from Echinococcus, Taenia, Mesocestoides and Hymenolepis genera. We classified them as Class I and II HDACs and analyzed their transcriptional expression levels throughout developmental stages of Echinococcus spp. We confirmed for the first time the complete HDAC8 nucleotide sequences from Echinococcus canadensis G7 and Mesocestoides corti. Homology models for these proteins showed particular structural features which differentiate them from HDAC8 from Homo sapiens. Furthermore, we showed that Trichostatin A (TSA), a pan-HDAC inhibitor, decreases the viability of M. corti, alters its tegument and morphology and produces an increment of the total amount of acetylated proteins, including acetylated histone H4. These results suggest that HDAC from cestodes are functional and might play important roles on survival and development. The particular structural features observed in cestode HDAC8 proteins suggest that these enzymes could be selectively targeted. This report provides the basis for further studies on cestode HDAC enzymes and for discovery of new HDAC inhibitors for the treatment of neglected diseases caused by cestode parasites.

Analysis of classical neurotransmitter markers in tapeworms: Evidence for extensive loss of neurotransmitter pathways.

Parasitic flatworms have complex neuromuscular systems that serve important functions in their life cycles. However, our understanding of neurotransmission in parasitic flatworms is limited. Pioneering studies have suggested the presence of several classical neurotransmitter systems, but their molecular components have not been characterized in most cases. Because these components are conserved in bilaterian animals, we searched the genomes of parasitic flatworms for orthologs of genes required for neurotransmitter synthesis, vesicular transport, reuptake, and reception. Our results indicate that tapeworms have lost the genes that are specifically required in other animals for synaptic signaling using the classical neurotransmitters dopamine, tyramine, octopamine, histamine and gamma-aminobutyric acid (GABA). These results imply that these signaling pathways are either absent in these parasites, or that they require completely different molecular components in comparison with other animals. The orthologs of genes related to histaminergic and GABA signaling are also missing in trematodes (although Schistosoma-specific histaminergic receptors have been previously described). In contrast, conserved genes required for glutamatergic, serotonergic and cholinergic signaling could be found in all analyzed flatworms. We analyzed the expression of selected markers of each pathway in the tapeworm Hymenolepis microstoma by whole-mount in situ hybridization. Each marker was specifically expressed in the nervous system, although with different patterns. In addition, we analyzed the expression of proprotein convertase 2 as a marker of peptidergic cells. This gene showed the widest expression in the nervous system, but was also expressed in other tissues, suggesting additional roles of peptidergic signaling in tapeworm development and reproduction.

Octopus maya parasites off the Yucatán Peninsula, Mexico. I. Faunal assemblages.

The red octopus Octopus maya Voss et Solís-Ramírez, 1966 is an endemic species found exclusively off the coast of the Yucatán Peninsula, Mexico; its fishery is one of the most important along the Atlantic coast of Mexico and the Caribbean Sea. To date, the parasite fauna of Octopus spp. in southern Mexico remains unknown. In this study, we present the parasite fauna of O. maya from 8 localities along the Yucatán Peninsula. From August 2009 to June 2010, a total of 1202 specimens of O. maya were caught by artisanal fisheries and examined. Twenty parasite taxa were recorded from all octopus examined: 7 cestodes, 8 digeneans, 3 nematodes, 1 copepod and 1 coccidian. All taxa are new records for this host species, and the sampled locations represent new records of the geographic distribution of these parasite taxa. The gills and the intestine were the micro-habitats in which the highest number of taxa were found. More than half of the parasites (13 taxa) that we found infected O. maya via its feeding habits, although a high number of taxa (n = 9) colonized via active transmission. Cestoda and Digenea were the taxonomic groups with the highest number of taxa. Prochristianella sp. showed the highest prevalence and mean abundance values in the localities where it was present. This work represents the first study on the parasite fauna of any cephalopod species in Mexico.

Hymenolepis microstoma (Cestoda: Hymenolepididae) en ratones caseros ( Mus musculus ) de Lima, Perú / Hymenolepis microstoma (Cestoda: Hymenolepididae) in house mice (Mus musculus) from Lima, Peru

Un total de 12 cestodos adultos se colectaron de los conductos biliares de ratones domésticos (Mus musculus) provenientes de Lima, Perú. Diversas características del escólex y proglotis maduros del cestodo fueron observadas para la identificación morfológica. Así mismo, se realizó un diagnóstico molecular mediante un PCR y secuenciación parcial del gen mitocondrial citocromo c oxidasa subunidad 1 (cox1). Todos los cestodos fueron identificados como Hymenolepis microstoma por morfología y métodos moleculares. El aislado de H. microstoma de Perú mostró una similitud de secuencia significativa (> 99%) con los aislados de H. microstoma previamente reportados. Nuestro informe confirma la presencia del parásito en ratones de Lima.

A total of 12 adult cestodes were collected from the bile ducts of domestic mice (Mus musculus) from Lima, Peru. Various features of the scolex and mature proglottids of the tapeworms were observed for morphological identification. A molecular diagnosis was performed by PCR-based partial sequencing of mitochondrial gene of cytochrome c oxidase subunit 1 (cox1). All cestodes were identified as Hymenolepis microstoma by morphology and molecular methods. The H. microstoma isolate from Peru showed significant sequence similarity with previously reported isolates of H. microstoma (>99%). Our report confirms the presence of the parasite in mice from Lima.

Comparative proteomics of the larval and adult stages of the model cestode parasite Mesocestoides corti.

Mesocestoides corti is a widely used model for the study of cestode biology, and its transition from the larval tetrathyridium (TT) stage to the strobilated, adult worm (ST) stage can be induced and followed in vitro. Here, a proteomic approach was used to describe and compare M. corti TT and ST protein repertories. Overall, 571 proteins were identified, 238 proteins in TT samples and 333 proteins in ST samples. Among the identified proteins, 207 proteins were shared by TTs and STs, while 157 were stage-specific, being 31 exclusive from TTs, and 126 from STs. Functional annotation revealed fundamental metabolic differences between the TT and the ST stages. TTs perform functions related mainly to basic metabolism, responsible for growth and vegetative development by asexual reproduction. STs, in contrast, perform a wider range of functions, including macromolecule biosynthetic processes, gene expression and control pathways, which may be associated to its proglottization/segmentation, sexual differentiation and more complex physiology. Furthermore, the generated results provided an extensive list of cestode proteins of interest for functional studies in M. corti. Many of these proteins are novel candidate diagnostic antigens, and/or potential targets for the development of new and more effective antihelminthic drugs. BIOLOGICAL SIGNIFICANCE: Cestodiases are parasitic diseases with serious impact on human and animal health. Efforts to develop more effective strategies for diagnosis, treatment or control of cestodiases are impaired by the still limited knowledge on many aspects of cestode biology, including the complex developmental processes that occur in the life cycles of these parasites. Mesocestoides corti is a good experimental model to study the transition from the larval to the adult stage, called strobilation, which occur in typical cestode life-cycles. The performed proteomics approach provided large-scale identification and quantification of M. corti proteins. Many stage-specific or differentially expressed proteins were detected in the larval tetrathyridium (TT) stage and in the strobilated, adult worm (ST) stage. Functional comparative analyses of the described protein repertoires shed light on function and processes associated to specific features of both stages, such as less differentiation and asexual reproduction in TTs, and proglottization/segmentation and sexual differentiation in ST. Moreover, many of the identified stage-specific proteins are useful as cestode developmental markers, and are potential targets for development of novel diagnostic methods and therapeutic drugs for cestodiases.

Parasites of the Southern silvery grebe Podiceps occipitalis (Aves, Podicipedidae) in Chile / Parasitas do mergulhão-de-orelha-amarela Podiceps occipitalis (Aves, Podicipedidae) no Chile

Abstract A total of 97 southern silvery grebes (Podiceps occipitalis), which died as the result of an oil spill on the coast of central Chile, were examined for ecto- and endoparasites. Two lice species including Aquanirmus rollandii (Philopteridae) and Pseudomenopon dolium (Menoponidae) were found from 6.2% (6/97) of birds. In 91.7% (89/97) of cases, grebes were infected with some kind of helminths. Three species of gastrointestinal helminths were detected: Eucoleus contortus (Nematoda), Profilicollis bullocki (Acanthocephala), and Confluaria sp. (Cestoda). In addition, Pelecitus fulicaeatrae (Nematoda) was removed from the tibiotarsal-tarsometatarsal articulation in 13.4% (13/97) of the specimens examined. To our knowledge, these are the first records of A. rollandii, E. contortus, and Confluaria sp. as parasites of P. occipitalis. In addition, these findings expand the distributional range of A. rollandii, E. contortus, P. fulicaeatrae, and Confluaria sp. to Chile.

Resumo Um total de 97 mergulhões-de-orelha-amarela (Podiceps occipitalis), que morreram devido a um derramamento de óleo na costa do Chile central, foram examinados em busca de parasitos internos e externos. Parasitos externos foram encontrados em 6,2% (6/97) das aves, com a identificação de duas espécies de piolhos: Aquanirmus rollandii (Philopteridae) e Pseudomenopon dolium (Menoponidae). Em 91,7% (89/97) dos casos, os mergulhões apresentaram algum tipo de parasito interno. Foram detectadas três espécies de parasitos gastrointestinais: Eucoleus contortus (Nematoda), Profilicollis bullocki (Acanthocephala) e Confluaria sp. (Cestoda). Além disso, Pelecitus fulicaeatrae (Nematoda) foi isolado das articulação tibiotársica e tarsometatarsal em 13,4% (13/97) das aves examinados. Estes resultados correspondem ao primeiro relato de A. rollandii, E. contortus e Confluaria sp. associados com P. occipitalis, e expandem a distribuição destes parasitos e P. fulicaeatrae para o Chile.

Cestode parasites release extracellular vesicles with microRNAs and immunodiagnostic protein cargo.

Intercellular communication is crucial in multiple aspects of cell biology. This interaction can be mediated by several mechanisms including extracellular vesicle (EV) transfer. EV secretion by parasites has been reported in protozoans, trematodes and nematodes. Here we report that this mechanism is present in three different species of cestodes, Taenia crassiceps, Mesocestoides corti and Echinococcus multilocularis. To confirm this we determined, in vitro, the presence of EVs in culture supernatants by transmission electron microscopy. Interestingly, while T. crassiceps and M. corti metacestodes secrete membranous structures into the culture media, similar vesicles were observed in the interface of the germinal and laminated layers of E. multilocularis metacestodes and were hardly detected in culture supernatants. We then determined the protein cargo in the EV-enriched secreted fractions of T. crassiceps and M. corti conditioned media by LC-MS/MS. Among the identified proteins, eukaryotic vesicle-enriched proteins were identified as expected, but also proteins used for cestode disease diagnosis, proteins related to neurotransmission, lipid binding proteins as well as host immunoglobulins and complement factors. Finally, we confirmed by capillary electrophoresis the presence of intravesicular RNA for both parasites and detected microRNAs by reverse transcription-PCR. This is the first report of EV secretion in cestode parasites and of an RNA secretion mechanism. These findings will provide valuable data not only for basic cestode biology but also for the rational search for new diagnostic targets.