DOCSLIB.ORG

Subclase Secernentea

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Subclase Secernentea Orden Ascaridida T. 21. ASCARIDIDOS. Generalidades y Clasificación. Incluye parásitos con tres labios de gran tamaño. En los machos, cuando existen alas caudales, éstas se localizan Ascaridioideos y Anisakoideos. lateralmente. 1. GENERALIDADES Y CLASIFICACIÓN Los ascarídidos son nematodos con fasmidios (quimiorreceptores posteriores); pertenecen por tanto a la Clase Secernentea. Los machos presentan generalmente alas caudales o bolsas copuladoras. Los ascarídidos de interés veterinario se clasifican en base al siguiente esquema taxonómico: Orden Ascaridida Superfamilia Ascaridoidea Familia Ascarididae Género Ascaris Género Parascaris Género Toxocara Género Toxascaris Fig. 1. Extremo caudal del macho en Ascarididae. Superfamilia Anisakoidea Familia Anisakidae Género Anisakis Superfamilia Ascaridoidea Género Contracaecum Género Phocanema Por lo general son nematodos de gran tamaño. No Género Pseudoterranova presentan cápsula bucal y el esófago carece de bulbo posterior Superfamilia Heterakoidea pronunciado. En algunas especies el esófago está seguido de un Familia Heterakidae: G. Heterakis ventrículo posterior corto que puede derivarse en un apéndice Familia Ascaridiidae: G. Ascaridia 1 ventricular, mientras que otras presentan una prolongación del 2.1. GÉNERO ASCARIS intestino en sentido craneal que se conoce como ciego intestinal (Fig. 12, Familia Anisakidae). Existen dos espículas en los machos Ascaris suum y el ciclo de vida puede ser directo o indirecto. Es un parásito del cerdo con distribución cosmopolita y de 2. FAMILIA ASCARIDIDAE considerable importancia económica. Sin embargo, su prevalencia está disminuyendo debido a los cada vez más frecuentes sistemas Los labios, que como característica del Orden están bien de producción intensiva y a la instauración de tratamientos desarrollados, presentan una serie de papilas labiales externas e antihelmínticos periódicos. Durante años se ha considerado internas, así como un borde denticular en su cara interna. Entre las sinónimo de la especie parásita del hombre Ascaris lumbricoides. bases de los dientes pueden existir pequeños interlabios. Sin embargo, actualmente se consideran especies diferentes. Aparte de dos espículas y alas caudales no muy desarrolladas, el extremos posterior de los machos está provisto de numerosas papilas pre y postcloacales (Fig. 1). Las hembras son ovíparas y suelen poner un elevado número de huevos, generalmente no segmentados cuando son liberados. Los huevos son redondeados u ovales y con una cubierta normalmente gruesa y rugosa. Al menos una muda la realizan dentro del huevo; éstos siempre eclosionan en el hospedador. La vulva se abre hacia la región media del cuerpo. Dentro de los géneros de mayor interés veterinario, las especies más importantes son las siguientes: Fig. 2. Vista frontal del extremo anterior de A. suum Ascaris suum Parascaris equorum Toxocara canis, T. cati, T. vitulorum Toxascaris leonina Morfología 2 Los machos miden de 15-25 cm por 3 mm y las hembras de los huevos. Aquí tiene lugar la siguiente muda (larva 3). Desde más de 40 cm por 5 mm. Por el tamaño, sólo pueden confundirse el hígado son vehiculados a través del corazón hacia los pulmones con el acantocéfalo Macrocanthorhynchus hirudinaceus, que y allí quedan retenidas a nivel de los capilares sanguíneos, aunque también puede parasitar el intestino delgado del cerdo. Ambos algunos pueden pasar a la circulación arterial y alcanzan otros sexos presentan una fila de dentículos diminutos en el borde más órganos como bazo y riñón. Las larvas 3 pasan de los capilares interno de los labios (Fig. 2). El extremo posterior del macho se alveolares hacia los alvéolos y van ascendiendo progresivamente ajusta a la descripción de la familia, y en la hembra la vulva se por el árbol bronquial y tráquea. A continuación pasan a faringe y abre al final del primer tercio del cuerpo. son deglutidas. En intestino tiene lugar el paso a larva 4, aunque algunos autores sostienen que esta tercera muda tendría lugar en el Ciclo biológico (Fig. 3) tracto respiratorio. Los adultos pueden encontrase en el intestino sobre los 50-55 días y a los 60-62 días ya pueden observarse Las hembras ponen hasta 1-1.6 millones de huevos al día, huevos en heces. La longevidad de los adultos oscila entre 3-4 que salen con las heces del hospedador y evolucionan en el medio meses, aunque puede extenderse hasta el año. hasta larva infectante en unos 10 días, dependiendo de la temperatura. Los huevos son muy resistentes a las condiciones Los huevos de Ascaris suum pueden ser ingeridos, adversas, como la congelación, la desecación y la exposición a eclosionar y las larvas resultantes migrar en numerosas especies, productos químicos. Pueden permanecer cinco años en el medio, incluida la especie humana. En el hombre, generalmente no tiene incluso más. Les afecta negativamente la exposición directa a la lugar una infección patente, aunque se han descrito infecciones luz solar y los lugares muy secos. accidentales. El desarrollo de A. lumbricoides en el cerdo se ha estudiado en más profundidad y sí se han conseguido desarrollar Aunque hay diversas teorías, se admite que el elemento infecciones patentes. infectante es la larva 2. Esta larva raramente eclosiona y los animales se infectan al ingerir huevos larvados con la comida o el Desde el punto de vista epidemiológico, es importante agua. Los lechones lactantes también pueden infectarse al lamer reseñar que las lombrices de tierra y los escarabajos que ingieren los huevos adheridos a la piel de la madre. huevos larvados de A. suum pueden actuar como hospedadores de transporte. Los huevos eclosionan en el intestino del cerdo, las larvas penetran en la mucosa, atraviesan la pared intestinal y, alcanzan el hígado siguiendo la corriente sanguínea hepatoportal. La llegada al hígado ocurre aproximadamente a las 24 horas de la ingestión 3 Fig. 3. Ciclo biológico de Ascaris suum: (A) Eliminación de hue vos por las heces; (B) huevo sin embrionar en el medio; (C) hue vo embrionado con L2 en el medio –elemento infectante-; (D) anélidos –hospedador de transporte-; (E) contagio oral por ingestión del elemento infectante; (F) eclosión y penetración de las L2 en la mucosa del intestino posterior; (G) migración hepát ica y desarrollo a L3; (H) migración pulmonar; (I) deglución de L 3 y desarrollo a L4 y a adultos en intestino delgado. 2.1. GÉNERO PARASCARIS Fig.4. Boca (A) y extremo posterior (B) de Parascaris equorum (Ascaris megalocephala o Ascaris equorum) Parascaris equorum. Morfología (Fig. 4) Es un parásito de equinos, incluyendo la cebra, que se distribuye en la mayor parte del mundo. Por su gran tamaño no es Presenta un cuerpo robusto, mayor que el de A. suum y sus posible confundirlo con otro nematodo del intestino del caballo. tres labios están separados por tres interlabios y divididos en dos porciones a nivel medio. El macho presenta pequeñas alas caudales y papilas, y la vulva de la hembra se abre al final del 4 primer cuarto del cuerpo. Los huevos son casi esféricos, con cáscara gruesa y rugosa y miden entre 90-100 µm de diámetro Se encuentra en el intestino delgado de perros y zorros, y (Fig.5). se distribuye en zonas subtropicales y templadas, disminuyendo su prevalencia hacia los polos. Ciclo biológico Morfología (Fig. 6) Es similar al de A. suum, siendo el periodo de prepatencia de unas 10 semanas. Los huevos pueden sobrevivir en el medio Son parásitos de tamaño grande, pudiendo medir los también durante largo tiempo. machos más de 10 cm y las hembras más de 18 cm. Presentan alas cervicales largas y el extremo anterior está inclinado ventralmente. Fig.5. Huevo de Parascaris equorum. 2.3. GÉNERO TOXOCARA Los miembros de este género presentan un ventrículo granular en la base del esófago, los ciegos intestinales están ausentes y no muestran interlabios. Las especies más importantes Fig. 6. Extremos anterior y posterior de Toxocara canis, son Toxocara canis y Toxocara cati. La especie Toxocara Toxocara cati y Toxascaris leonina. vitulorum es la responsable de la ascarididosis de los rumiantes. Toxocara canis 5 Los machos muestran una especie de apéndice terminal en Adultos de T. canis Huevos unicelulares la cola y alas caudales. Los huevos son subesféricos (75-90 µm), en intestino delgado en heces ligeramente marrones y con una cáscara gruesa que suele Maduración de las larvas a presentar pequeñas hendiduras. Son liberados por heces con una a las 3 semanas postparto ari m sola célula. a Larvas en los m pulmones de los Ciclo biológico (Fig.7) cachorros Migración traqueal Infección prenatal Es un ciclo complejo porque según la edad del hospedador Infección trans El pueden darse diferentes formas de transmisión y de migración Reactivación de las perro L2 en la preñez Migración ingiere Huevos con larvaria. somática huevos L2, enquistada en los larva infectante tejidos de la madre (L2) en el suelo Migración traqueal Ocurre en cachorros desde las pocas semanas hasta los tres Migración meses. Los huevos alcanzan el estadio infectante a los 10-15 días El perro depreda traqueal al hospedador abortiva en condiciones óptimas. Tras ser ingeridos, llegan a duodeno, paraténico donde eclosionan liberando una larva 2. Este estadio larvario Huevos penetra en la pared intestinal, vía hepatoportal las larvas alcanzan ingeridos por hospedadores el hígado y a continuación el pulmón a través de las venas L2 enquistada Migración somática paraténicos hepáticas y las arterias cardiacas y pulmonares. Vía linfática en los tejidos de hosp. pueden llegar a los ganglios mesentéricos y a través del conducto paraténicos torácico llegar de esta otra forma al corazón. Una vez en pulmón, migran hacia los alvéolos, los bronquiolos y la tráquea, pudiendo en ocasiones ser deglutidos y pasar hacia el tracto gastrointestinal. El paso a larva 3 ocurre en los pulmones, la tráquea o el esófago, y Fig. 7. Ciclo biológico de T. canis a larva 4 en el intestino delgado. El periodo de prepatencia es de aproximadamente 4-5 semanas. 6 Cuando los cachorros van creciendo va disminuyendo la gestación, las L2 ingeridas también pueden ir al útero y contribuir tendencia a que se produzca una migración traqueal y lo que tiene a la infección de los cachorros.
Load more

Recommended publications
  • Baylisascariasis
    Baylisascariasis Importance Baylisascaris procyonis, an intestinal nematode of raccoons, can cause severe neurological and ocular signs when its larvae migrate in humans, other mammals and birds. Although clinical cases seem to be rare in people, most reported cases have been Last Updated: December 2013 serious and difficult to treat. Severe disease has also been reported in other mammals and birds. Other species of Baylisascaris, particularly B. melis of European badgers and B. columnaris of skunks, can also cause neural and ocular larva migrans in animals, and are potential human pathogens. Etiology Baylisascariasis is caused by intestinal nematodes (family Ascarididae) in the genus Baylisascaris. The three most pathogenic species are Baylisascaris procyonis, B. melis and B. columnaris. The larvae of these three species can cause extensive damage in intermediate/paratenic hosts: they migrate extensively, continue to grow considerably within these hosts, and sometimes invade the CNS or the eye. Their larvae are very similar in appearance, which can make it very difficult to identify the causative agent in some clinical cases. Other species of Baylisascaris including B. transfuga, B. devos, B. schroeder and B. tasmaniensis may also cause larva migrans. In general, the latter organisms are smaller and tend to invade the muscles, intestines and mesentery; however, B. transfuga has been shown to cause ocular and neural larva migrans in some animals. Species Affected Raccoons (Procyon lotor) are usually the definitive hosts for B. procyonis. Other species known to serve as definitive hosts include dogs (which can be both definitive and intermediate hosts) and kinkajous. Coatimundis and ringtails, which are closely related to kinkajous, might also be able to harbor B.
    [Show full text]
  • Strongyloides Myopotami (Secernentea: Strongyloididae) from the Intestine of Feral Nutrias (Myocastor Coypus) in Korea
    ISSN (Print) 0023-4001 ISSN (Online) 1738-0006 Korean J Parasitol Vol. 52, No. 5: 531-535, October 2014 ▣ CASE REPORT http://dx.doi.org/10.3347/kjp.2014.52.5.531 Strongyloides myopotami (Secernentea: Strongyloididae) from the Intestine of Feral Nutrias (Myocastor coypus) in Korea Seongjun Choe, Dongmin Lee, Hansol Park, Mihyeon Oh, Hyeong-Kyu Jeon, Keeseon S. Eom* Department of Parasitology, Medical Research Institute and Parasite Resource Bank, Chungbuk National University School of Medicine, Cheongju 361-763, Korea Abstract: Surveys on helminthic fauna of the nutria, Myocastor coypus, have seldom been performed in the Republic of Korea. In the present study, we describe Strongyloides myopotami (Secernentea: Strongyloididae) recovered from the small intestine of feral nutrias. Total 10 adult nutrias were captured in a wetland area in Gimhae-si (City), Gyeongsangnam- do (Province) in April 2013. They were transported to our laboratory, euthanized with ether, and necropsied. About 1,300 nematode specimens were recovered from 10 nutrias, and some of them were morphologically observed by light and scanning electron microscopies. They were 3.7-4.7 (4.0± 0.36) mm in length, 0.03-0.04 (0.033) mm in width. The worm dimension and other morphological characters, including prominent lips of the vulva, blunted conical tail, straight type of the ovary, and 8-chambered stoma, were all consistent with S. myopotami. This nematode fauna is reported for the first time in Korea. Key words: Strongyloides myopotami, nutria, Myocastor coypus The nutria (Myocastor coypus) or coypu rat is a large rodent notic diseases caused by viruses, bacteria, and parasites [1].
    [Show full text]
  • Angiostrongylus Cantonensis in Recife, Pernambuco, Brazil
    Letter Arq Neuropsiquiatr 2009;67(4):1093-1096 AlicAtA DiSEASE Neuroinfestation by Angiostrongylus cantonensis in Recife, Pernambuco, Brazil Ana Rosa Melo Correa Lima1, Solange Dornelas Mesquita2, Silvana Sobreira Santos1, Eduardo Raniere Pessoa de Aquino1, Luana da Rocha Samico Rosa3, Fábio Souza Duarte3, Alessandra Oliveira Teixeira1, Zenize Rocha da Silva Costa4, Maria Lúcia Brito Ferreira5 Angiostrongylus cantonensis, is a nematode in the panying the patient reported that she had presented a rash as- Secernentea class, Strongylidae order, Metastrongylidæ sociated with joint pain, followed by progressive difficulty in superfamily and Angiostrongylidæ family1, and is the walking for 30 days, which was associated with sleepiness over most common cause of human eosinophilic meningi- the last 15 days. tis worldwide. This parasite has rats and other mammals In the patient’s past history, there were references to mental as definitive hosts and snails, freshwater shrimp, fish, retardation and lack of ability to understanding simple orders. frogs and monitor lizards as intermediate hosts1. Mam- She presented independent gait and had frequently run away mals are infected by ingestion of intermediate hosts from home into the surrounding area. There was mention of in- and raw/undercooked snails or vegetables, contain- voluntary movements, predominantly of the upper limbs, which ing third-stage larvae2. Once infested, the larvae pen- intensified after the change of health status that motivated the etrate the vasculature of the intestinal tract and pro- current search for medical assistance. In November 2007, the pa- mote an inflammatory reaction with eosinophilia and tient presented with generalized tonic-clonic seizures and was lymphocytosis. This produces rupture of the blood- medicated with carbamazepine, 200 mg/twice a day.
    [Show full text]
  • Worms, Nematoda
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Faculty Publications from the Harold W. Manter Laboratory of Parasitology Parasitology, Harold W. Manter Laboratory of 2001 Worms, Nematoda Scott Lyell Gardner University of Nebraska - Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/parasitologyfacpubs Part of the Parasitology Commons Gardner, Scott Lyell, "Worms, Nematoda" (2001). Faculty Publications from the Harold W. Manter Laboratory of Parasitology. 78. https://digitalcommons.unl.edu/parasitologyfacpubs/78 This Article is brought to you for free and open access by the Parasitology, Harold W. Manter Laboratory of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications from the Harold W. Manter Laboratory of Parasitology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Published in Encyclopedia of Biodiversity, Volume 5 (2001): 843-862. Copyright 2001, Academic Press. Used by permission. Worms, Nematoda Scott L. Gardner University of Nebraska, Lincoln I. What Is a Nematode? Diversity in Morphology pods (see epidermis), and various other inverte- II. The Ubiquitous Nature of Nematodes brates. III. Diversity of Habitats and Distribution stichosome A longitudinal series of cells (sticho- IV. How Do Nematodes Affect the Biosphere? cytes) that form the anterior esophageal glands Tri- V. How Many Species of Nemata? churis. VI. Molecular Diversity in the Nemata VII. Relationships to Other Animal Groups stoma The buccal cavity, just posterior to the oval VIII. Future Knowledge of Nematodes opening or mouth; usually includes the anterior end of the esophagus (pharynx). GLOSSARY pseudocoelom A body cavity not lined with a me- anhydrobiosis A state of dormancy in various in- sodermal epithelium.
    [Show full text]
  • Fibre Couplings in the Placenta of Sperm Whales, Grows to A
    news and views Most (but not all) nematodes are small Daedalus and nondescript. For example, Placento- T STUDIOS nema gigantissima, which lives as a parasite Fibre couplings in the placenta of sperm whales, grows to a CS./HOL length of 8 m, with a diameter of 2.5 cm. The The nail, says Daedalus, is a brilliant and free-living, marine Draconema has elongate versatile fastener, but with a fundamental O ASSO T adhesive organs on the head and along the contradiction. While being hammered in, HO tail, and moves like a caterpillar. But the gen- it is a strut, loaded in compression. It must BIOP eral uniformity of most nematode species be thick enough to resist buckling. Yet has hampered the establishment of a classifi- once in place it is a tie, loaded in tension, 8 cation that includes both free-living and par- and should be thin and flexible to bear its asitic species. Two classes have been recog- load efficiently. He is now resolving this nized (the Secernentea and Adenophorea), contradiction. based on the presence or absence of a caudal An ideal nail, he says, should be driven sense organ, respectively. But Blaxter et al.1 Figure 2 The bad — eelworm (root knot in by a force applied, not to its head, but to have concluded from the DNA sequences nematode), which forms characteristic nodules its point. Its shaft would then be drawn in that the Secernentea is a natural group within on the roots of sugar beet and rice. under tension; it could not buckle, and the Adenophorea.
    [Show full text]
  • Symbionts and Diseases Associated with Invasive Apple Snails
    Symbionts and diseases associated with invasive apple snails Cristina Damborenea, Francisco Brusa and Lisandro Negrete CONICET, División Zoología Invertebrados, Museo de La Plata (FCNyM-UNLP), Paseo del Bosque, 1900 La Plata, Argentina. Email: [email protected], fbrusa@ fcnym.unlp.edu.ar, [email protected] Abstract This contribution summarizes knowledge of organisms associated with apple snails, mainly Pomacea spp., either in a facultative or obligate manner, paying special attention to diseases transmitted via these snails to humans. A wide spectrum of epibionts on the shell and operculum of snails are discussed. Among them algae, ciliates, rotifers, nematodes, flatworms, oligochaetes, dipterans, bryozoans and leeches are facultative, benefitting from the provision of substrate, transport, access to food and protection. Among obligate symbionts, five turbellarian species of the genusTemnocephala are known from the branchial cavity, with T. iheringi the most common and abundant. The leech Helobdella ampullariae also spends its entire life cycle inside the branchial cavity; two copepod species and one mite are found in different sites inside the snails. Details of the nature of the relationships of these specific obligate symbionts are poorly known. Also, extensive studies of an intracellular endosymbiosis are summarized. Apple snails are the first or second hosts of several digenean species, including some bird parasites.A number of human diseases are transmitted by apple snails, angiostrongyliasis being the most important because of the potential seriousness of the disease. Additional keywords: Ampullariidae, Angiostrongylus, commensals, diseases, epibionts, parasites, Pomacea, symbiosis 73 Introduction The term “apple snail” refers to a number of species of freshwater snails belonging to the family Ampullariidae (Caenogastropoda) inhabiting tropical and subtropical regions (Hayes et al., 2015).
    [Show full text]
  • Gastric Nematode Diversity Between Estuarine and Inland Freshwater
    International Journal for Parasitology: Parasites and Wildlife 3 (2014) 227–235 Contents lists available at ScienceDirect International Journal for Parasitology: Parasites and Wildlife journal homepage: www.elsevier.com/locate/ijppaw Gastric nematode diversity between estuarine and inland freshwater populations of the American alligator (Alligator mississippiensis, daudin 1802), and the prediction of intermediate hosts Marisa Tellez a,*, James Nifong b a Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA b Fisheries and Aquatic Sciences, University of Florida, Gainesville, FL, USA ARTICLE INFO ABSTRACT Article history: We examined the variation of stomach nematode intensity and species richness of Alligator mississippiensis Received 11 June 2014 from coastal estuarine and inland freshwater habitats in Florida and Georgia, and integrated prey content Revised 23 July 2014 data to predict possible intermediate hosts. Nematode parasitism within inland freshwater inhabiting Accepted 24 July 2014 populations was found to have a higher intensity and species richness than those inhabiting coastal es- tuarine systems. This pattern potentially correlates with the difference and diversity of prey available Keywords: between inland freshwater and coastal estuarine habitats. Increased consumption of a diverse array of Alligator mississippiensis prey was also correlated with increased nematode intensity in larger alligators. Parasitic nematodes Ascarididae Georgia Dujardinascaris waltoni, Brevimulticaecum
    [Show full text]
  • Burrowing Nematode Radopholus Similis (Cobb, 1893) Thorne, 1949 (Nematoda: Secernentea: Tylenchida: Pratylenchidae: Pratylenchinae)1 Nicholas Sekora and William T
    EENY-542 Burrowing Nematode Radopholus similis (Cobb, 1893) Thorne, 1949 (Nematoda: Secernentea: Tylenchida: Pratylenchidae: Pratylenchinae)1 Nicholas Sekora and William T. Crow2 Introduction by fine textured soils rich in organic matter. However, soil texture plays a less important role on nematode population Radopholus similis, the burrowing nematode, is the most levels on banana (O’Bannon 1977). economically important nematode parasite of banana in the world. Infection by burrowing nematode causes toppling disease of banana, yellows disease of pepper and spreading Life Cycle and Biology decline of citrus. These diseases are the result of burrowing Burrowing nematode is an endoparasitic migratory nema- nematode infection destroying root tissue, leaving plants tode, meaning it completes its life cycle within root tissue. with little to no support or ability to take up water and All motile juvenile stages and females can infect root tissue translocate nutrients. Because of the damage that it causes at any point along the length of a root. After root penetra- to citrus, ornamentals and other agricultural industries, tion, these life stages mainly feed and migrate into the worldwide, burrowing nematode is one of the most regu- cortical parenchyma and also into the stele. Mature males lated nematode plant pests (Hockland et al. 2006). of burrowing nematode are not infective. As the mature females migrate through root tissue, they lay eggs that are Distribution produced through either sexual reproduction with males or by hermaphroditistim (Thorne 1961, Kaplan and Burrowing nematode is native to Australasia, but is found worldwide in tropical and subtropical regions of Africa, Opperman 2000). Once an egg hatches, the emergent Asia, Australia, North and South America, and many second-stage juvenile can migrate within the root and island regions.
    [Show full text]
  • Epidemiology of Angiostrongylus Cantonensis and Eosinophilic Meningitis
    Epidemiology of Angiostrongylus cantonensis and eosinophilic meningitis in the People’s Republic of China INAUGURALDISSERTATION zur Erlangung der Würde eines Doktors der Philosophie vorgelegt der Philosophisch-Naturwissenschaftlichen Fakultät der Universität Basel von Shan Lv aus Xinyang, der Volksrepublik China Basel, 2011 Genehmigt von der Philosophisch-Naturwissenschaftlichen Fakult¨at auf Antrag von Prof. Dr. Jürg Utzinger, Prof. Dr. Peter Deplazes, Prof. Dr. Xiao-Nong Zhou, und Dr. Peter Steinmann Basel, den 21. Juni 2011 Prof. Dr. Martin Spiess Dekan der Philosophisch- Naturwissenschaftlichen Fakultät To my family Table of contents Table of contents Acknowledgements 1 Summary 5 Zusammenfassung 9 Figure index 13 Table index 15 1. Introduction 17 1.1. Life cycle of Angiostrongylus cantonensis 17 1.2. Angiostrongyliasis and eosinophilic meningitis 19 1.2.1. Clinical manifestation 19 1.2.2. Diagnosis 20 1.2.3. Treatment and clinical management 22 1.3. Global distribution and epidemiology 22 1.3.1. The origin 22 1.3.2. Global spread with emphasis on human activities 23 1.3.3. The epidemiology of angiostrongyliasis 26 1.4. Epidemiology of angiostrongyliasis in P.R. China 28 1.4.1. Emerging angiostrongyliasis with particular consideration to outbreaks and exotic snail species 28 1.4.2. Known endemic areas and host species 29 1.4.3. Risk factors associated with culture and socioeconomics 33 1.4.4. Research and control priorities 35 1.5. References 37 2. Goal and objectives 47 2.1. Goal 47 2.2. Objectives 47 I Table of contents 3. Human angiostrongyliasis outbreak in Dali, China 49 3.1. Abstract 50 3.2.
    [Show full text]
  • Tokorhabditis N. Gen
    www.nature.com/scientificreports OPEN Tokorhabditis n. gen. (Rhabditida, Rhabditidae), a comparative nematode model for extremophilic living Natsumi Kanzaki1, Tatsuya Yamashita2, James Siho Lee3, Pei‑Yin Shih4,5, Erik J. Ragsdale6 & Ryoji Shinya2* Life in extreme environments is typically studied as a physiological problem, although the existence of extremophilic animals suggests that developmental and behavioral traits might also be adaptive in such environments. Here, we describe a new species of nematode, Tokorhabditis tufae, n. gen., n. sp., which was discovered from the alkaline, hypersaline, and arsenic‑rich locale of Mono Lake, California. The new species, which ofers a tractable model for studying animal‑specifc adaptations to extremophilic life, shows a combination of unusual reproductive and developmental traits. Like the recently described sister group Auanema, the species has a trioecious mating system comprising males, females, and self‑fertilizing hermaphrodites. Our description of the new genus thus reveals that the origin of this uncommon reproductive mode is even more ancient than previously assumed, and it presents a new comparator for the study of mating‑system transitions. However, unlike Auanema and almost all other known rhabditid nematodes, the new species is obligately live‑bearing, with embryos that grow in utero, suggesting maternal provisioning during development. Finally, our isolation of two additional, molecularly distinct strains of the new genus—specifcally from non‑extreme locales— establishes a comparative system for the study of extremophilic traits in this model. Extremophilic animals ofer a window into how development, sex, and behavior together enable resilience to inhospitable environments. A challenge to studying such animals has been to identify those amenable to labo- ratory investigation1,2.
    [Show full text]
  • Toxocara Cati (Schrank, 1788) (Nematoda, Ascarididae) in Different Wild Feline Species in Brazil: New Host Records
    Biotemas, 26 (3): 117-125, setembro de 2013 http://dx.doi.org/10.5007/2175-7925.2013v26n3p117117 ISSNe 2175-7925 Toxocara cati (Schrank, 1788) (Nematoda, Ascarididae) in different wild feline species in Brazil: new host records Moisés Gallas * Eliane Fraga da Silveira Departamento de Biologia, Museu de Ciências Naturais Universidade Luterana do Brasil, CEP 92425-900, Canoas – RS, Brasil *Autor para correspondência [email protected] Submetido em 07/03/2013 Aceito para publicação em 14/05/2013 Resumo Toxocara cati (Schrank, 1788) (Nematoda, Ascarididae) em diferentes espécies de felinos silvestres no Brasil: novos registros de hospedeiros. Esta é a primeira descrição detalhada de Toxocara cati parasitando felinos na América do Sul. Dezessete felinos silvestres (Leopardus colocolo, Leopardus geoffroyi, Leopardus tigrinus e Puma yagouaroundi) atropelados foram coletados em diferentes municípios do Estado do Rio Grande do Sul, Brasil. A morfometria de machos e fêmeas permitiu a identificação de espécimes como T. cati. Os helmintos foram encontrados no estômago e intestino dos hospedeiros com prevalência de 66,6% em L. colocolo, L. geoffroyi e L. tigrinus; e 60% em P. yagouaroundi. Foram calculados os parâmetros ecológicos para cada hospedeiro e, L. colocolo teve a maior intensidade de infecção (22,5 helmintos/hospedeiro). Este é o primeiro registro de T. cati parasitando quatro espécies de felinos silvestres no Sul do Brasil e, dois novos registros de hospedeiros para esse parasito. Palavras-chave: Felinos; Leopardus; Puma; Sul do Brasil; Toxocara Abstract This is the first detailed description ofToxocara cati parasitizing felines in South America. Seventeen run over wild felines (Leopardus colocolo, Leopardus geoffroyi, Leopardus tigrinus, and Puma yagouaroundi) were collected from different towns in the State of Rio Grande do Sul, Brazil.
    [Show full text]
  • Gastrointestinal Parasites of Maned Wolf
    http://dx.doi.org/10.1590/1519-6984.20013 Original Article Gastrointestinal parasites of maned wolf (Chrysocyon brachyurus, Illiger 1815) in a suburban area in southeastern Brazil Massara, RL.a*, Paschoal, AMO.a and Chiarello, AG.b aPrograma de Pós-Graduação em Ecologia, Conservação e Manejo de Vida Silvestre – ECMVS, Universidade Federal de Minas Gerais – UFMG, Avenida Antônio Carlos, 6627, CEP 31270-901, Belo Horizonte, MG, Brazil bDepartamento de Biologia da Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo – USP, Avenida Bandeirantes, 3900, CEP 14040-901, Ribeirão Preto, SP, Brazil *e-mail: [email protected] Received: November 7, 2013 – Accepted: January 21, 2014 – Distributed: August 31, 2015 (With 3 figures) Abstract We examined 42 maned wolf scats in an unprotected and disturbed area of Cerrado in southeastern Brazil. We identified six helminth endoparasite taxa, being Phylum Acantocephala and Family Trichuridae the most prevalent. The high prevalence of the Family Ancylostomatidae indicates a possible transmission via domestic dogs, which are abundant in the study area. Nevertheless, our results indicate that the endoparasite species found are not different from those observed in protected or least disturbed areas, suggesting a high resilience of maned wolf and their parasites to human impacts, or a common scenario of disease transmission from domestic dogs to wild canid whether in protected or unprotected areas of southeastern Brazil. Keywords: Chrysocyon brachyurus, impacted area, parasites, scat analysis. Parasitas gastrointestinais de lobo-guará (Chrysocyon brachyurus, Illiger 1815) em uma área suburbana no sudeste do Brasil Resumo Foram examinadas 42 fezes de lobo-guará em uma área desprotegida e perturbada do Cerrado no sudeste do Brasil.
    [Show full text]