Modulatory actions of Echinococcus granulosus antigen B on macrophage inflammatory activation.

Cestodes use own lipid-binding proteins to capture and transport hydrophobic ligands, including lipids that they cannot synthesise as fatty acids and cholesterol. In E. granulosus s.l., one of these lipoproteins is antigen B (EgAgB), codified by a multigenic and polymorphic family that gives rise to five gene products (EgAgB8/1-5 subunits) assembled as a 230 kDa macromolecule. EgAgB has a diagnostic value for cystic echinococcosis, but its putative role in the immunobiology of this infection is still poorly understood. Accumulating research suggests that EgAgB has immunomodulatory properties, but previous studies employed denatured antigen preparations that might exert different effects than the native form, thereby limiting data interpretation. This work analysed the modulatory actions on macrophages of native EgAgB (nEgAgB) and the recombinant form of EgAg8/1, which is the most abundant subunit in the larva and was expressed in insect S2 cells (rEgAgB8/1). Both EgAgB preparations were purified to homogeneity by immunoaffinity chromatography using a novel nanobody anti-EgAgB8/1. nEgAgB and rEgAgB8/1 exhibited differences in size and lipid composition. The rEgAgB8/1 generates mildly larger lipoproteins with a less diverse lipid composition than nEgAgB. Assays using human and murine macrophages showed that both nEgAgB and rEgAgB8/1 interfered with in vitro LPS-driven macrophage activation, decreasing cytokine (IL-1ß, IL-6, IL-12p40, IFN-ß) secretion and ·NO generation. Furthermore, nEgAgB and rEgAgB8/1 modulated in vivo LPS-induced cytokine production (IL-6, IL-10) and activation of large (measured as MHC-II level) and small (measured as CD86 and CD40 levels) macrophages in the peritoneum, although rEgAgB8/1 effects were less robust. Overall, this work reinforced the notion that EgAgB is an immunomodulatory component of E. granulosus s.l. Although nEgAgB lipid's effects cannot be ruled out, our data suggest that the EgAgB8/1 subunit contributes to EgAgB´s ability to regulate the inflammatory activation of macrophages.

Larvae trypanorhynch (Cestoda) infecting the dusky flounder, Syacium papillosum (Paralichthyidae: Pleuronectiformes) in the continental shelf of the Yucatan Peninsula, Mexico.

Trypanorhynch cestode larvae were found parasitizing specimens of dusky flounder Syacium papillosum (Linnaeus, 1758) in the Southeastern Gulf of Mexico (s-GoM). Plerocercoids were recovered from a total of 194 flatfish, embedded in the intestine and stomach wall. Trypanorhynch were identified using morphology and a molecular phylogeny using newly sequenced partial 28S (region D1-D3) ribosomal DNA in combination with data derived from other species of trypanorhynchs available from GenBank. Larvae representing three genera of trypanorhynch cestodes, Nybelinia Poche, 1926; Kotorella Euzet & Radujkovic, 1989 and Oncomegas Dollfus, 1929 were found in dusky flounder specimens in the s-GoM. These plerocercoids represent six species: Nybelinia sp. 1, Nybelinia sp. 2, Nybelinia sp. 3, Nybelinia sp. 4, Kotorella pronosoma (Stossich, 1901) and Oncomegas wageneri (Linton, 1890) Dollfus, 1929. All cestode specimens in this study represent new locality records for their respective species.

First Report of Intestinal Cestode Infection in a Berylline Hummingbird (Saucerottia beryllina) in Mexico.

BACKGROUND: Up to now, five cestode species have been reported infecting five hummingbird species. To date, there have been no reports of cestode infections in hummingbirds in Mexico. METHODS: A Berylline hummingbird (Saucerottia beryllina) was found dead in a backyard at Toluca City, Mexico, and a window collision was assumed as the cause of death. The bird was preserved in 10% neutral buffered formalin for routine histological examination. RESULTS: At the histological study, liver parenchymal disruption was observed. This lesion could be the result of the assume collision. No lesions were observed in other tissues examined. Conspicuous cestode structures were observed in the lumen of the small intestine. Structure of cestodes, as revealed from histological sections, suggests their position in the genus Anonchotaenia Cohn, 1900 (family Paruterinidae). CONCLUSION: This is the first report of intestinal cestodosis in a Berylline hummingbird (S. beryllina) in Mexico.

microRNA silencing in a whole worm cestode model provides insight into miR-71 function.

Parasites belonging to the class Cestoda include zoonotic species such as Echinococcus spp. and Taenia spp. that cause morbidity and mortality in endemic areas, mainly affecting pastoral and rural communities in low income countries but also upper middle income countries. Cestodes show remarkable developmental plasticity, implying tight regulation of gene expression throughout their complex life cycles. Despite the recent availability of genomic data for cestodes, little progress was made on postgenomic functional studies. MicroRNAs (miRNAs) are key components of gene regulatory systems that guide diverse developmental processes in multicellular organisms. miR-71 is a highly expressed miRNA in cestodes, which is absent in vertebrates and targets essential parasite genes, representing a potential key player in understanding the role of miRNAs in cestodes biology. Here we used transfection with antisense oligonucleotides to perform whole worm miRNA knockdown in tetrathyridia of Mesocestoides vogae (syn. Mesocestoides corti), a laboratory model of cestodes. We believe this is the first report of miRNA knockdown at the organism level in these parasites. Our results showed that M. vogae miR-71 is involved in the control of strobilation in vitro and in the establishment of murine infection. In addition, we identified miR-71 targets in M. vogae, several of them being de-repressed upon miR-71 knockdown. This study provides new knowledge on gene expression regulation in cestodes and suggests that miRNAs could be evaluated as new selective therapeutic targets for treating Neglected Tropical Diseases prioritised by the World Health Organization.

Parasitic helminths of Halichoeres bivittatus (Pisces: Labridae) from the southwestern Gulf of México / Helmintos parásitos de halichoeres bivittatus (pisces: labridae) del suroeste del golfo de méxico

RESUMEN Un total de 326 helmintos parásitos fueron recuperados de 94 especímenes de Halichoeres bivittatus (Pisces: Labridae) en dos sitios de la zona arrecifal en los límites del Parque Nacional Sistema Arrecifal Veracruzano, Veracruz, México, el suroeste del Golfo de México: Punta Gorda (n = 51) y Mata de Uva (n = 43). Los peces fueron capturados entre mayo y septiembre de 2001. Cada muestra se analizó a nivel de comunidad componente e infracomunidad. Tres especies de helmintos se localizaron en intestino: Nicolla halichoeri (Digenea) considerándose nuevo registro de localidad, Procamallanus (Spirocamallanus) garnotus (Nematoda) es nuevo registro de hospedero, y las larvas de Tetraphyllidea gen. sp. (Cestoda) fueron los parásitos con mayor prevalencia e intensidad promedio para cada sitio. La riqueza de especies para ambos sitios fue de S = 3 y el índice de diversidad de Shannon-Wiener (Punta Gorda, H'= 0,42; Mata de Uva, H'= 0,49) fueron inferiores a los registrados para las comunidades hospedero-parásito de lábridos y de hospederos de la localidad. No hubo correlación entre el número total de especies o el número total de helmintos con respecto a la longitud total o el peso del hospedero. El análisis de las curvas de especies acumuladas para la comunidad componente sugirió, que el inventario de especies de helmintos estaba casi completo para ambos sitios. La abundancia de larvas del céstodo ubica a H. bivittatus como hospedero intermediario del parásito.

ABSTRACT A total of 326 parasitic helminths were obtained from 94 specimens of Halichoeres bivittatus (Pisces: Labridae) at two sites in the reef zone at the limits of the Veracruz Reef System National Park, Veracruz, Mexico, southwestern Gulf of Mexico: Punta Gorda (n = 51) and Mata de Uva (n = 43). Fish were caught from May to September 2001. Each sample was examined at the levels of the component community and infracommunity. Three parasitic helminth species were found in intestines: Nicolla halichoeri (Digenea: Plagiorchiida: Opecoelidae) is a new geographic record, Procamallanus (Spirocamallanus) garnotus (Nematoda) is a new host record, and larvae of Tetraphyllidea gen. sp. (Cestoda) were the parasites with the highest prevalence and the average intensity at both sites. Species richness (S = 3) and the Shannon-Wiener diversity index (H'= 0,42; 0,49) were lower than those previously estimated for the labrid host-parasite community in the study area. No correlations between the total number of species or the total number of helminths and the total length or weight of the host were observed. An analysis of the accumulated curve for the component community suggested that the inventory of helminth species was almost complete for both sites. The abundance of cestode larvae infers H. bivittatus is an intermediate host of the parasite.

Parvitaenia cochlearii (Cestoda: Gryporhynchidae) en cultivo de chame Dormitator latifrons en Ecuador

RESUMEN Objetivo. Identificar y determinar los parámetros de infección del metacestodo Parvitaenia en diferentes fases de cultivo de Dormitator latifrons y evaluar los daños histológicos. Materiales y métodos. Se revisaron 45 ejemplares, 15 en cada fase (pre-cría, pre-engorda y engorda) para identificar el metacestodo y los daños tisulares provocados. Se calculó la prevalencia, intensidad e intensidad mediana. Se evaluó la diferencia de la intensidad mediana entre fase de cultivo mediante la prueba de medianas de Mood. La longitud total, peso, factor de condición de Fulton e índice hepatosomático se correlacionó con la intensidad mediante una correlación lineal. Los daños tisulares fueron evaluados en fragmentos de hígado. Resultados. Se encontró un total de 29151 cestodos, identificados como Parvitaenia cochlearii. La prevalencia del cestodo fue de 100%, la intensidad mediana varió de 22 a 625 individuos y mostró diferencias significativas entre fases de cultivo (X2= 29.391; p<0.0001). La intensidad mostró una correlación positiva moderada con la longitud total de los peces (r2= 0.45; p<0.05) y una correlación baja con el peso (r2= 0.38; p<0.05). En hígados poco parasitados se observó fibrosis y congestión alrededor de los quistes. En hígados con altos niveles de infección se observó reducción del parénquima, fibrosis e incremento de centros melanomacrófagos. Conclusiones. Este es el primer reporte de P. cochlearii en D. latifrons de cultivo. Nuestros resultados sugieren que existe una tendencia de acumulación de cestodos durante el crecimiento de los peces, lo cual podría tener implicaciones negativas para el comercio.

ABSTRACT Objective. To identify and determine the infection parameters of the metacestode Parvitaenia in different culture stages of Dormitator latifrons and to evaluate the histological damage caused by this parasite. Materials and methods. Forty-five specimens were examined, 15 in each phase: prebreeding, pre-fattening, and fattening, to identify the metacestode and tissue damage caused using conventional parasitology and histology techniques. Prevalence, intensity, and median intensity were calculated. A Mood's median test evaluated the difference between intensity per culture phase. Total length, weight, condition factor, and hepatosomatic index were correlated with intensity by linear correlation analysis. Liver fragments were evaluated to identify the tissue damage. Results. A total of 29,151 cestodes were found and were identified as Parvitaenia cochlearii. Cestode prevalence was 100% in each culture phase. The median intensity ranged from 22 to 625 individuals and showed significant differences between culture phases (X2 = 29.391; p<0.0001). Intensity showed moderate positive correlation with total fish length (r2 = 0.45; p<0.05) and low correlation with weight (r2 = 0.38; p<0.05). In less parasitized livers, fibrosis and congestion around the cysts were observed, while in livers with high levels of infection, parenchymal reduction, fibrosis, and increase in melanomacrophage centers were observed. Conclusions. This is the first report of P. cochlearii on D. latifrons in aquaculture. We suggest that there is a tendency for cestode accumulation during fish growth, which could have negative implications for trade.

Cell repertoire and proliferation of germinative cells of the model cestode Mesocestoides corti.

The phylum Platyhelminthes shares a unique population of undifferentiated cells responsible for the proliferation capacity needed for cell renewal, growth, tissue repair and regeneration. These cells have been extensively studied in free-living flatworms, whereas in cestodes the presence of a set of undifferentiated cells, known as germinative cells, has been demonstrated in classical morphology studies, but poorly characterized with molecular biology approaches. Furthermore, several genes have been identified as neoblast markers in free-living flatworms that deserve study in cestode models. Here, different cell types of the model cestode Mesocestoides corti were characterized, identifying differentiated and germinative cells. Muscle cells, tegumental cells, calcareous corpuscle precursor cells and excretory system cells were identified, all of which are non-proliferative, differentiated cell types. Besides those, germinative cells were identified as a population of small cells with proliferative capacity in vivo. Primary cell culture experiments in Dulbecco's Modified Eagle Medium (DMEM), Echinococcus hydatid fluid and hepatocyte conditioned media in non-reductive or reductive conditions confirmed that the germinative cells were the only ones with proliferative capacity. Since several genes have been identified as markers of undifferentiated neoblast cells in free-living flatworms, the expression of pumilio and pL10 genes was analysed by qPCR and in situ hybridization, showing that the expression of these genes was stronger in germinative cells but not restricted to this cell type. This study provides the first tools to analyse and further characterise undifferentiated cells in a model cestode.

Molecular characterization of the serotonergic transporter from the cestode Echinococcus granulosus: pharmacology and potential role in the nervous system.

Echinococcus granulosus, the etiological agent of human cystic echinococcosis (formerly known as hydatid disease), represents a serious worldwide public health problem with limited treatment options. The essential role played by the neuromuscular system in parasite survival and the relevance of serotonin (5-HT) in parasite movement and development make the serotonergic system an attractive source of drug targets. In this study, we cloned and sequenced a cDNA coding for the serotonin transporter from E. granulosus (EgSERT). Bioinformatic analyses suggest that EgSERT has twelve transmembrane domains with highly conserved ligand and ionic binding sites but a less conserved allosteric site compared with the human orthologue (HsSERT). Modeling studies also suggest a good degree of conservation of the overall structure compared with HsSERT. Functional and pharmacological studies performed on the cloned EgSERT confirm that this protein is indeed a serotonin transporter. EgSERT is specific for 5-HT and does not transport other neurotransmitters. Typical monoamine transport inhibitors also displayed inhibitory activities towards EgSERT, but with lower affinity than for the human SERT (HsSERT), suggesting a high divergence of the cestode transporter compared with HsSERT. In situ hybridization studies performed in the larval protoscolex stage suggest that EgSERT is located in discrete regions that are compatible with the major ganglia of the serotonergic nervous system. The pharmacological properties, the amino acidic substitutions at important functional regions compared with the HsSERT, and the putative role of EgSERT in the nervous system suggest that it could be an important target for pharmacological intervention.

New arrangement of three genera of fish tapeworms (Cestoda: Proteocephalidae) in catfishes (Siluriformes) from the Neotropical Region: taxonomic implications of molecular phylogenetic analyses.

Tapeworms (Cestoda: Proteocephalidae) are the dominant component of communities of intestinal parasites in pimelodid and other catfishes (Siluriformes) from South America. Even though these parasites have been studied intensively over more than one century, molecular taxonomy and phylogenetics have questioned their morphology-based classification, thus raising doubts about the systematic value of traits commonly used to circumscribe individual taxa. In the present study, members of three morphologically well-characterized genera of proteocephalids from pimelodid (Hemisorubim platyrhynchos and Sorubim lima) and auchenipterid (Ageneiosus inermis) catfishes from the Paraná or Amazon River basins were subjected to DNA sequencing of the large subunit nuclear ribosomal RNA (lsrDNA) and complete mitochondrial cytochrome c oxidase subunit I (COI). Phylogenetic analyses revealed the sister relationship between Manaosia bracodemoca and Mariauxiella piscatorum, and among Mariauxiella pimelodi and Ageneiella brevifilis. As a result, Mar. piscatorum and A. brevifilis are transferred to Manaosia and Mariauxiella, respectively, as Manaosia piscatorum n. comb. and Mariauxiella brevifilis n. comb., and the genus Ageneiella is suppressed. Diagnoses of Manaosia and Mariauxiella are amended. In addition, the present study revealed misidentification of tapeworms whose sequences are deposited in the GenBank database.

Prevalence of gastrointestinal parasites in three groups of domestic poultry managed under backyard system in the Savanna subregion, Department of Sucre, Colombia.

OBJECTIVE: To identify the prevalence of gastrointestinal parasites that affect the backyard poultry system in the Savanna region, Department of Sucre, Colombia. MATERIALS AND METHODS: Fecal samples were collected from 860 native birds, both hens (Gallus domesticus), ducks (Anas platyrhynchos domesticus), and turkeys (Meleagris gallopavo), regardless of age and sex. Samples were processed using direct techniques with ZnSO4 and indirect methods such as modified Sloss. Data were presented as frequencies, and the nonparametric odds ratio test was used for two independent samples. RESULTS: A total of 77.3% (665/860) of the birds were infected with one or more species of gastrointestinal parasites. Among the nematodes, Capillaria spp. (45.6%), Ascaridia galli (18.4%), Heterakis gallinarum (59.4%), Syngamus trachea (38.9%), Tetrameres spp. (25.2%), and Strongylus spp. (12.2%) were recorded. The cestodes were Choanotaenia infundibulum (22.6%), Davainea proglottina (42.3%), Raillietina spp. (58.3%), and Hymenolepis spp. (54.7%), while only Eimeria spp. (90%) was recorded as protozoa. CONCLUSIONS: The study showed a high incidence of gastrointestinal parasite infestations, the most common species being Hymenolepis spp., Eimeria spp., Raillietina spp., and Heterakis gallinarum.

Frecuencia de infección por cestodos en el Laboratorio Nacional de Referencia de Parasitismo Intestinal-IPK, Cuba, 2010-2018 / Frequency of cestode infection at the Intestinal Parasitic Disease National Reference Laboratory of Pedro Kourí Institute in Cuba, 2010-2018

Introdución: Los cestodos son helmintos parásitos del humano y de animales, con complejos ciclos de vida. En las infecciones por los cestodos no existen programas de desparasitación masiva implementados para disminuir la carga parasitaria de estos a nivel mundial, dada la baja prevalencia que se informa en estudios epidemiológicos. Existen pocos trabajos sobre la epidemiología y la detección de estas infecciones en la literatura internacional. Objetivo: Describir la frecuencia de infección de cestodos y sus características epidemiológicas. Métodos: Estudio descriptivo y retrospectivo, realizado entre el 3 de enero de 2010 y 28 de diciembre de 2018. Se analizaron todas las muestras de heces, parásitos adultos y metacestodos enviadas de la red de Salud al Laboratorio Nacional de Referencia de Parasitismo Intestinal-IPK. El universo de estudio estuvo constituido por 9833 muestras, que fueron enviadas mayoritariamente de la provincia La Habana. Resultados: La infección por Inermicapsifer madagascariensis predominó en niños menores de 5 años (69,6 por ciento; IC 95 por ciento: 47,1-86,8). La infección intestinal por Taenia spp. se diagnosticó prinipalmente en pacientes entre 15 y 65 años de edad (88,2 por ciento; IC95 por ciento: 63,6-98,5). De los 47 casos positivos a la infección por cestodos, 24 pertenecieron al sexo femenino (51,1 por ciento; IC95 por ciento: 35,7-66,4) y 23 al sexo masculino (48,9 por ciento; IC95 por ciento: 33,6-64,3). No hubo diferencias significativas entre la infección por Inermicapsifer madagascariensis y Taenia spp. y el sexo de los pacientes (p˃ 0,05). Conclusiones: Aunque la frecuencia de infección de las cestodiosis detectadas es baja, estos resultados pudieran ser útiles para un control integrado de las principales cestodioisis en los diferentes grupos etarios(AU)

Introduction: Cestodes are helminths of complex life cycles which may infect animals and humans. No mass deworming programs are in place to reduce the worldwide parasite load of cestodes, given the low prevalence reported by epidemiological research. Few studies are available in the international literature about the epidemiology and detection of these infections. Objective: Describe the frequency of cestode infection and its epidemiological characteristics. Methods: A retrospective descriptive study was conducted from 3 January 2010 to 28 December 2018. Evaluation was performed of all the samples of fecal matter, adult parasites and metacestodes submitted by the health care network to the Intestinal Parasitic Disease National Reference Laboratory at Pedro Kourí Institute. The study universe was 9 833 samples, mostly received from the province of Havana. Results: Inermicapsifer madagascariensis infection prevailed among children aged under 5 years (69.6 percent; CI 95 percent: 47.1-86.8). Taenia sp. intestinal infection was mainly diagnosed in patients aged 15-65 years (88.2 percent; CI 95 percent: 63.6-98.5). Of the 47 cestode infection positive cases, 24 were female (51.1 percent; CI 95 percent: 35.7-66.4) and 23 were male (48.9 percent; CI 95 percent: 33.6-64.3). No significant differences were found between Inermicapsifer madagascariensis and Taenia sp. infection and the sex of patients (p˃ 0.05). Conclusions: Although the frequency of cestode infection detected is low, these results could be useful for an integrated control of the main cestode infections affecting the different age groups(AU)

Diversity of helminth parasites of freshwater fish in the headwaters of the Coatzacoalcos River, in Oaxaca, Mexico.

We documented the diversity of helminth parasites of 25 fish species from 8 families occurring in the headwaters of the Coatzacoalcos river basin. This river flows along the border between the states of Oaxaca and Veracruz, in the region of the Isthmus of Tehuantepec, in south-eastern Mexico, and in northern Central America. We recorded 48 species, representing 44 genera and 29 helminth families. Six of the 25 fish species were examined for helminths for the first time; 60 new host records were reported. Nematodes and trematodes were the most abundant taxonomic groups. The helminth fauna from our study area consists of primarily central American species. Most species recorded from this area have also been captured from freshwater bodies between the Isthmus of Tehuantepec and the Isthmus of Panama. However, three species, including an acanthocephalan and two nematodes, are likely endemic to this area. We argue that, in contrast to the presence of larval helminths, which mostly depends on the geographical location of water bodies, adult helminths are an integral and consistent component of the regional community. Data on taxonomic composition and distribution of helminth fauna reported in this paper, contribute to a better understanding of this faunal component in northern Central America (CA). Furthermore, knowledge of helminth parasites of freshwater fish from Neotropical Mexico and CA facilitates prediction of which parasite species is likely to infect fish in a specific geographical area.

Ocurrencia de Mesocestoides sp. (Cestoda: Mesocestoididae) en el zorro andino (Lycalopex culpaeus) / Occurrence of Mesocestoides sp. (Cestoda: Mesocestoididae) in the Andean fox (Lycalopex culpaeus)

Resumen En este trabajo, informamos Mesocestoides sp. parasitando a un individuo de Lycalopex culpaeus (zorro andino) procedente del Abra la Raya, departamento de Cusco, Perú. El individuo fue necropsiado en el Instituto Veterinario de Investigaciones Tropicales y de Altura (IVITA), sede de Maranganí. Numerosos cestodos se recolectaron del intestino delgado y se analizaron morfológicamente. Se proporciona una breve descripción morfológica de los especímenes de Mesocestoides, así como una discusión con respecto de especies anteriormente registradas para Perú.

Abstract In this work, we report Mesocestoides sp. parasiting one individual of Lycalopex culpaeus (Andean fox) captured from the Abra la Raya, Department of Cusco, Peru. The individual was necropsed in the Instituto Veterinario de Investigaciones Tropicales y de Altura (IVITA), Maranganí Headquarters. Numerous cestodes collected from the small intestine and morphologically analyzed. We provided a brief morphological description of Mesocestoides specimenes, and discuss concerning previous Mesocestoides species registered in Peru.

Fatty acid-binding proteins in Echinococcus spp.: the family has grown.

Fatty acid-binding proteins (FABPs) are small intracellular proteins that reversibly bind fatty acids and other hydrophobic ligands. In cestodes, due to their inability to synthesise fatty acids de novo, FABPs have been proposed as essential proteins, and thus, as possible drug targets and/or carriers against these parasites. We performed data mining in Echinococcus multilocularis and Echinococcus granulosus genomes in order to test whether this family of proteins is more complex than previously reported. By exploring the genomes of E. multilocularis and E. granulosus, six genes coding for FABPs were found in each organism. In the case of E. granulosus, all of them have different coding sequences, whereas in E. multilocularis, two of the genes code for the same protein. Remarkably, one of the genes (in both cestodes) encodes a FABP with a C-terminal extension unusual for this family of proteins. The newly described genes present variations in their structure in comparison with previously described FABP genes in Echinococcus spp. The coding sequences for E. multilocularis were validated by cloning and sequencing. Moreover, differential expression patterns of FABPs were observed at different stages of the life cycle of E. multilocularis by exploring transcriptomic data from several sources. In summary, FABP family in cestodes is far more complex than previously thought and includes new members that seem to be only present in flatworms.

Krill Nyctiphanes simplex gonad affection associated with acute-intensity phyllobothriid plerocercoid infection.

This is the first acute-intensity record of helminths parasitizing the subtropical krill Nyctiphanes simplex Hansen, 1911. We briefly describe the pathology of infection of Phyllobothriidae gen. sp. plerocercoids parasitizing N. simplex in the Gulf of California. Infection occurred with a very low prevalence (P = 0.06%, n = 1563 specimens), although acute-intensity exceeded several hundred plerocercoids crowding the hemocoel in one female host. Nyctiphanes simplex showed inflammatory response of hemocyte-based infiltration, nodule formation, and presumptive melanization. Remarkably, cestodes invade and supplant the gonad, causing atretic oocytes and severe tissue destruction in the gonad likely leading to castration and cell death in connective tissue of the infected organs suggesting that acute-intensity infection exceeds the krill's reaction capacity. Thus, Phyllobothriidae gen. sp. negatively affects the host by depleting its fitness, leading to total castration to prevent/block host reproduction.

First report of cestode infection in the crustacean Artemia persimilis from Southern Chilean Patagonia and its relation with the Neotropical aquatic birds.

The brine shrimp genus Artemia Leach (Crustacea, Branchiopoda), a keystone group in hipersaline wetlands all over the world, offers an excellent model to study species interactions (parasitism) and to explore "hidden fauna" (avian endoparasites). The present study is the first report on the parasite infection of the South American species Artemia persimilis from the Southern Chilean Patagonia (50°S-53°S). Samples were collected in Los Cisnes and Amarga lagoons, the two most austral populations of this crustacean described to date, during two seasons (spring and autumn). A total of 98 larvae of cestodes of the family Hymenolepididae (Cestoda, Cyclophyllidea) were found and identified as belonging to the following taxa: Confluaria podicipina (adult parasitic in grebes), Flamingolepis sp. (a cestode parasite of flamingos), Fimbriarioides (?) sp. (adults of the species of this genus infect waterfowl and shorebirds) and Wardium sp. (definitive host unknown, most probably charadriiform birds). This is a new geographical record of C. podicipina and the genus Fimbriarioides for the Neotropical Region, the latter being the most widely distributed species at both localities and seasons surveyed, and the only species recorded in autumn (April). Cestode community composition in Los Cisnes population was characterised by dominance of Flamingolepis sp., representing more than 65% of the total cestode species recorded, whereas in the Amarga population the most abundant parasite (>83%) was Fimbriarioides (?) sp. Significant seasonal variations were detected in Los Cisnes lagoon for Flamingolepis sp. and C. podicipina, with exclusive presence of them in spring (November). Besides providing novel information on cestodes infection in A. persimilis, this study provides new data on the life cycle of cestodes of Neotropical aquatic birds such as South American flamingos and grebes. Our finding expands the knowledge on the biodiversity and population dynamics of extreme and unique environments from high latitudes (Patagonia) and makes evident the need of further taxonomical and ecological studies for better understanding the life cycles of avian helminth parasites in the Neotropics and the role of aquatic invertebrates in them.

Seasonal patterns in risk factors for Taenia solium transmission: a GPS tracking study of pigs and open human defecation in northern Peru.

BACKGROUND: Taenia solium (cysticercosis) is a parasitic cestode that is endemic in rural populations where open defecation is common and free-roaming pigs have access to human feces. The purpose of this study was to examine the roaming patterns of free-range pigs, and identify areas where T. solium transmission could occur via contact with human feces. We did this by using GPS trackers to log the movement of 108 pigs in three villages of northern Peru. Pigs were tracked for approximately six days each and tracking was repeated in the rainy and dry seasons. Maps of pig ranges were analyzed for size, distance from home, land type and contact with human defecation sites, which were assessed in a community-wide defecation survey. RESULTS: Consistent with prior GPS studies and spatial analyses, we found that the majority of pigs remained close to home during the tracking period and had contact with human feces in their home areas: pigs spent a median of 79% (IQR: 61-90%) of their active roaming time within 50 m of their homes and a median of 60% of their contact with open defecation within 100 m of home. Extended away-from-home roaming was predominately observed during the rainy season; overall, home range areas were 61% larger during the rainy season compared to the dry season (95% CI: 41-73%). Both home range size and contact with open defecation sites showed substantial variation between villages, and contact with open defecation sites was more frequent among pigs with larger home ranges and pigs living in higher density areas of their village. CONCLUSIONS: Our study builds upon prior work showing that pigs predominately roam and have contact with human feces within 50-100 m of the home, and that T. solium transmission is most likely to occur in these concentrated areas of contact. This finding, therefore, supports control strategies that target treatment resources to these areas of increased transmission. Our finding of a seasonal trend in roaming ranges may be useful for control programs relying on pig interventions, and in the field of transmission modeling, which require precise estimates of pig behavior and risk.

Cloning, expression, purification, and kinetic characterization of mitochondrial thioredoxin (TsTrx2), cytosolic thioredoxin (TsTrx1), and glutaredoxin (TsGrx1) from Taenia solium.

We report the complete coding sequences of mitochondrial thioredoxin (TsTrx2) and glutaredoxin (TsGrx1) from the cysticerci of T. solium. The full-length DNA of the TsTrx2 gene shows two introns of 88 and 77 bp and three exons. The TsTrx2 gene contains a single ORF of 423 bp, encoding 140 amino acid residues with an estimated molecular weight of 15,560 Da. A conserved C64NPC67 active site and a 30-amino acid extension at its N-terminus were identified. An insulin reduction reaction was used to determine whether it was a functional recombinant protein. The full-length DNA of the TsGrx1 gene shows one intron of 39 bp and a single ORF of 315 bp, encoding 105 amino acid residues with an estimated molecular weight of 12,582 Da. Sequence analysis revealed a conserved dithiol C34PYC37 active site, GSH-binding motifs (CXXC, Lys and Gln/Arg, TVP, and CXD), and a conserved Gly-Gly motif. The r-TsGrx1 kinetic constants for glutathione (GSH) and 2-hydroxyethyl disulfide (HED) were determined. In addition, cytosolic thioredoxin (TsTrx1), as reported by (Jiménez et al., Biomed Res Int 2015:453469, 2015), was cloned and expressed, and its catalytic constants were obtained along with those of the other two reductases. Rabbit-specific antibodies showed immune cross-reactions between TsTrx1 and TsTrx2 but not with TsGrx1. Both TsTGRs as reported by (Plancarte and Nava, Exp Parasitol 149:65-73, 2015) were biochemically purified to obtain and compare the catalytic constants for their natural substrates, r-TsTrx1, and r-TsTrx2, compared to those for Trx-S2E. coli. In addition, we determined the catalytic differences between the glutaredoxin activity of the TsTGRs compared with r-TsGrx1. These data increase the knowledge of the thioredoxin and GSH systems in T. solium, which is relevant for detoxification and immune evasion.

Gastrointestinal helminths of two populations of wild pigeons (Columba livia) in Brazil / Helmintos gastrointestinais de duas populações de pombos de vida livre (Columba livia) no Brasil

The present study analyzed gastrointestinal helminth communities in 265 wild pigeons (Columba livia) living in the municipalities of São Paulo and Tatuí, state of São Paulo, Brazil, over a one-year period. The birds were caught next to grain storage warehouses and were necropsied. A total of 790 parasites comprising one nematode species and one cestode genus were recovered from 110 pigeons, thus yielding an overall prevalence of 41.5%, mean intensity of infection of 7.2 ± 1.6 (range 1-144) and discrepancy index of 0.855. Only 15 pigeons (5.7%) presented mixed infection. The helminths isolated from the birds were Ascaridia columbae (Ascaridiidae) and Raillietina sp. (Davaineidae). The birds weights differed according to sex but this did not influence the intensity of infection. The overall prevalence and intensity of infection did not differ between the sexes, but the prevalence was higher among the birds from Tatuí (47.8%). The gastrointestinal helminth community of C. livia was characterized in the two areas studied and parasite homogeneity was observed over the 12 months analyzed at both locations. These results make contributions to the current literature on health aspects of wild C. livia populations.(AU)

O presente estudo analisou comunidades gastrointestinais de helmintos em 265 indivíduos de Columba livia de vida livre nos municípios de São Paulo e Tatuí, estado de São Paulo, Brasil, durante um ano. As aves foram capturadas em áreas de armazenamento de grãos e sementes e necropsiadas. Um total de 790 parasitos representando uma espécie de nematódeo e um gênero de cestoide foram recuperados de 110 pombos com uma prevalência geral de 41,5%, intensidade média de infecção de 7,2 ± 1,6 (amplitude 1-144) e índice de discrepância de 0,855. Somente 15 (5,7%) pombos tiveram uma infecção mista. Os helmintos isolados das aves foram Ascaridia columbae (Ascaridiidae) e Raillietina sp. (Davaineidae). O peso das aves foi diferente entre os sexos, mas não influenciou a intensidade de infecção. A prevalência geral e a intensidade de infecção não foram diferentes entre sexo, mas a prevalência foi maior nas aves de Tatuí (47,8%). A comunidade gastrointestinal de helmintos de C. livia foi caracterizada nas duas áreas estudadas e uma homogeneidade de parasitos foi observada nos 12 meses analisados, em ambas localidades. Os resultados contribuem para a literatura atual sobre aspectos sanitários de populações de C. livia em vida livre.(AU)