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The Helminthological Collection of the Oswaldo Cruz Institute is the biggest in Latin America and it is among the largest collections at worldwide reference level, with around 40,000 sets of specimens and approximately one million individual specimens. It contains helminths parasites of vertebrate and invertebrate animals that form part of the fauna of Brazil and other countries. The samples comprise holotypes, paratypes and representative specimens of Platyhelminthes, Acanthocephala, Nematoda and other non-helminth phyla, such as Annelida and Arthropoda. Some of the samples preserved in liquid media were found to have dried out. This made it impossible to analyze these samples morphologically for taxonomic purposes. The aim of this study was to test techniques used for rehydration of the tegument of specimens that had been found to have dried out and present protocols for such techniques. A total of 528 specimens that either no longer were immersed in preservatives or had already dried out were analyzed: 96 digenetic trematodes, 45 cestodes, 22 acanthocephalans, 357 nematodes, four hirudineans and four pentastomid crustaceans. The technique of rehydration using only distilled water on the specimens proved to be efficient for recovering tegument malleability, for all samples analyzed in this present study.

Two species of intestinal Capillariidae were hitherto known from the Neotropic cormorant Phalacrocorax brasilianus, Baruscapillaria spiculata (Freitas, 1933), and Baruscapillaria appendiculata (Freitas, 1933). The original descriptions are very short and brief, and further reports of both species are scarce and/or confusing. This paper provides a morphological redescription and molecular characterization, based on the partial 18S rDNA gene, of B. spiculata specimens parasitizing the Neotropic cormorant in two continental lagoons from Buenos Aires province, Argentina. Both morphological and morphometrical differences between B. spiculata and B. appendiculata are highlighted on the examination of available type material. Additionally, two previous reports of B. appendiculata from Mexico and Brazil are discussed. A phylogenetic analysis conducted on specimens of B. spiculata and 46 other capillariid isolates available from the GenBank demonstrated a sister-taxon relationship between our specimens and the type species of Baruscapillaria. But, at the same time, significant genetic distances between both taxa showed an interesting variability of the genus Baruscapillaria. The probable division of this genus into multiple genera could probably be confirmed through integrative studies including more species.

Fish consumption plays an important role in human diet. Hoplias malabaricus, commonly known as traíra, is a freshwater fish widely appreciated in several Brazilian states and frequently infected by Eustrongylides sp. fourth-instar larvae (L4). The aim of the present study was to evaluate allergenic potential of Eustrongylides sp. L4 crude extract (CEE). BALB/c mice were immunized intraperitoneally (IP) by 10 μg CEE with 2 mg of aluminum hydroxide on days 0 and 35. Specific IgG and IgE antibody levels were determined after immunization and cellular immunity was evaluated by assessing intradermal reaction in ear pavilion. Epicutaneous sensitization was performed in dorsal region by antigen exposure using a Finn-type chamber containing 50 μg of CEE or saline solution, followed by evaluation of specific antibody levels. IP immunization resulted in a gradual increase in IgG antibody levels and transitory IgE production. Significant increase in ear thickness was observed in cellular hypersensitivity reaction. In case of antigen exposure by epicutaneous route, CEE was able to induce meaningfully increased levels of specific IgG and IgE antibodies as well as heightened cellular immunity. Both intraperitoneal immunization and epicutaneous contact with Eustrongylides sp. larval antigens were observed for first time to be capable of inducing immunological sensitization in mice.

Atractis thapari Petter, 1966, an atractid nematode, was collected parasitizing the large intestine of tortoises of the species Chelonoidis carbonarius (Spix, 1824) (Cc) and C. denticulatus (Linnaeus, 1766) (Cd) (Testudinidae) in the Zoobotanical Park of the municipality of Teresina, state of Piauí, Brazil. Taxonomic identification was based on morphological and morphometrical features, and using bright-field and scanning electron microscopy. The present study adds new observations on the morphology of A. thapari, mainly relating to mouth papillae, the excretory pore, deirids, and male and female posterior ends. The parasitic indices of prevalence (P), mean intensity (MI), mean abundance (MA) and range of infection (RI) for A. thapari in these two tortoise species were: P = 100%, MI = 154,667, MA = 154,667, RI = 5,500-588,500 (Cc); P = 100%, MI = 93,639, MA = 93,639, RI = 1,000-224,500 (Cd). This report confirms the occurrence of A. thapari in Neotropical region, South America, Brazil, and extends its occurrences to a new host, the tortoise C. carbonarius. Adjustment of host management with the aim of improving hygiene and health conditions is suggested.

Chapiniella variabilis (Chapin, 1924), a strongylid nematode, was collected parasitizing the large intestine of the tortoises Chelonoidis carbonarius (Spix, 1824) (Cc) and C. denticulatus (Linnaeus, 1766) (Cd) in the Zoobotanical Park of the municipality of Teresina, state of Piauí, Brazil. The taxonomic identification was based on morphological and morphometric features, using bright-field and scanning electron microscopy. The present study adds new observations on the morphology, mainly relating to the mouth papillae, external and internal leaf-crown elements, excretory pore, deirids and male and female posterior end. The parasitic indices of prevalence (P), mean intensity (MI), mean abundance (MA) and range of infection (RI) of C. variabilis in these two tortoise species were: P = 100%, MI = 833.3, MA = 833.3, RI = 500-1,500 (Cc); P = 100%, MI = 472.2, MA = 472.2, RI = 333-500 (Cd). This record expands occurrences of C. variabilis to a new host, C. carbonarius, and to another state in Brazil, in the Neotropical region of South America. Adjustment to host management with the aim of improving hygiene and health conditions is suggested.

Between January and August 2012, thirty specimens of Cynoscion guatucupa (Cuvier, 1830) caught off coast of the municipality of Itajaí, state of Santa Catarina, Brazil (26° 54' 28″ S and 48° 39' 43″ W) and commercialized in the state of Rio de Janeiro were investigated for the presence of zoonotic nematodes. In total 853 larvae of four nematode parasite species were found. There were three species of Anisakidae: three larvae of Anisakis sp., with prevalence (P) of 10%, mean intensity (MI) of 1.0, mean abundance (MA) of 0.1 and infection site (IS) in the mesentery; five of Terranova sp. with P = 13.3%, MI = 1.25, MA = 0.17, range of infection (RI) from 1 to 2 and IS = mesentery; and seven of Contracaecum sp. with P = 6.6%, MI = 3.5, MA = 0.23, RI = 1 to 4 and IS = mesentery and abdominal cavity. There was one species of Raphidascarididae: 838 larvae of Hysterothylacium deardorffoverstreetorum with P = 83.3%, MI = 33.52, MA = 27.93, RI = 1 to 219 and IS = mesentery, liver serosa and abdominal cavity. This is the first report of larvae of Anisakis sp. and Contracaecum sp in C. guatucupa in Brazil. Hysterothylacium deardorffoverstreetorum; Anisakis sp.; Terranova sp.; Contracaecum sp.; Cynoscion guatucupa.

The aim of this study was to evaluate the tegument, musculature and mesentery of 102 specimens of Hoplerytrinus unitaeniatus, 104 of Hoplias malabaricus and 101 of Pygocentrus nattereri, from Arari Lake, Marajó Island, State of Pará, Brazil. Were identified the nematodes Contracaecum sp., Eustrongylides sp. and Procamallanus sp. Contracaecum sp. was the most prevalent, with rates of 84.31% (H. unitaeniatus), 95.19% (H. malabaricus), and 89.11% (P. nattereri). The highest prevalences of Eustrongylides sp. occurred in H. unitaeniatus (56.86%) and H. malabaricus (53.84%). Procamallanus sp. was only collected in the mesentery. Specimens of Eustrongylides sp. collected from the musculature were 91.9% of its population. Among the nematodes found in the mesentery, 98.34% were Contracaecum sp. with a mean intensity (MI) of 7.92 ± 8.11 (H. unitaeniatus), 8.49 ± 8.34 (H. malabaricus) and 7 ± 6.40 (P. nattereri). Contracaecum sp. presented the highest MI (8.49 ± 8.34) and mean abundance (8.09 ± 8.34). The highest MI values were observed in the mesentery. Eustrongylides sp. presented MI of 2.65 ± 3.21 (H. unitaeniatus), 3.41 ± 3.27 (H. malabaricus) and 2.17 ± 1.18 (P. nattereri). Nematodes with zoonotic potential that were found with high prevalence, shows the importance of actions by the health authorities.