Abstract Abstract: Trichiurus lepturus (Actinopterygii, Perciformes) is a commercially and economically important fish. A total of 60 specimens of this cutlassfish were collected of the coast the municipalities of Niterói and Cabo Frio, state of Rio de Janeiro, Brazil. The fish were measured, necropsied, filleted and had their organs investigated for digenetic trematodes. Taxonomic identification was based on morphological and morphometric characters. The specimens of T. lepturus were parasitized with adult specimens of Lecithochirium monticellii. Parasite indices of prevalence, intensity, mean intensity, abundance, mean abundance, range of infection, and site of infection of parasitic species were evaluated. Notes on the taxonomy of the parasite were also included. This is the first report of L. monticellii parasitizing T. lepturus in Brazil.

Entre julho e dezembro de 2013, foram adquiridos 30 espécimes de Priacanthus arenatus comercializados nos municípios de Niterói e Rio de Janeiro, no estado do Rio de Janeiro. Os peixes foram necropsiados e filetados para investigação da presença de larvas de nematoides. Do total, 20 (66,7%) peixes estavam parasitados com larvas de nematoides. Foram coletadas no total 2024 larvas, das quais, 30 larvas de terceiro estágio de Anisakis sp. com prevalência (P) = 20%, abundância média (AM) = 1 e intensidade média (IM) = 5, tendo como sítios de in fecção (SI) ceco, estômago, fígado e mesentério; e 1994 larvas de terceiro estágio (1757 encistadas e 237 livres) de Hysterothylacium deardorffoverstreetorum com P = 66,7%, AM = 66,5 e IM = 99,7e SI = baço, ceco, estô mago, fígado, mesentério e musculatura abdominal. Este é o primeiro registro de larvas de H. deardorffoverstree torum e Anisakis sp. parasitando P. arenatus.

From July to December, 2013, thirty Priacanthus arenatus specimens commercialized in the cities of Niterói and Rio de Janeiro, State of Rio de Janeiro, were acquired. The fish were necropsied and filleted to investigate the presence of nematode larvae. Twenty fish (66.7%) out of the total were parasitized by nematode larvae. A total of 2024 larvae were collected; among them, 30 third-instar larvae of Anisakis sp. showed prevalence (P) = 20%, mean abundance (MA) = 1, and the mean intensity (MI) = 5, and infection sites (IS) = caecum, stomach, liver, and mesentery; and 1,994 third-instar larvae (1,757 encysted and 237 free) of Hysterothylacium deardorffoverstreetorum with P = 66.7%, MA = 66.5, and MI = 99.7, and IS = spleen, caecum, stomach, liver, mesentery, and abdominal muscle. This is the first study to report H. deardorffoverstreetorum and Anisakis sp. larvae parasitizing P. arenatus.

Espécies de peixes da Ilha de Marajó, Estado do Pará, Brasil, foram examinadas para identificar os trematódeos parasitando 102 Hoplerytrinus unitaeniatus (jejú) e 104 Hoplias malabaricus (traíra). Identificados como Clinostomatopsis sorbens e Ithyoclinostomum dimorphum. Os índices parasitários de C. sorbens de H. unitaeniatus e H. malabaricus, foram 43,14% e 30,77% de prevalência, 2,52 e 1,84 de intensidade média, 1,09 e 0,57 de abundância média e 1 a 9 e 1 a 7 de variação da amplitude de infecção, respectivamente, em ambos o sítio de infecção foi o mesentério. Os índices parasitários de I. dimorphum de H. unitaeniatus foram 2,94% de prevalência, 2,66 de intensidade média, 0,08 de abundância média, 1 a 4 de variação da amplitude de infecção, e os sítios de infecção foram o mesentério e a musculatura. Metacercárias de I. dimorphum foram coletadas na musculatura de um espécime de H. malabaricus, com 0,96% de prevalência, com intensidade de infecção de 2 parasitos e 0,02 de abundância. São apresentadas novos dados sobre a morfologia das estruturas externas e internas. Este é o primeiro registro de metacercárias de C. sorbens e de I. dimorphum em peixes amazônicos.

Species of fish of Marajó Island, State of Pará, Brazil, were examined to identify the trematodes parasitizing 102 Hoplerytrinus unitaeniatus (gold wolf fish) and 104 Hoplias malabaricus (thraira). Metacercariae of two species of trematodes, 170 specimens of Clinostomatopsis sorbens and 10 Ithyoclinostomum dimorphum were found and identified. The parasitary indices of C. sorbens from H. unitaeniatus and H. malabaricus, were 43.14% and 30.77% for prevalence, 2.52 and 1.84 for mean intensity, 1.09 and 0.57 for mean abundance and 1 to 9 and 1 to 7 for range of infection, respectively, on both fish the site of infection was the mesentery. The parasitary indices of I. dimorphum from H. unitaeniatus were 2.94% for prevalence, 2.66 for mean intensity, 0.08 for mean abundance, 1 to 4 for range of infection, and the sites of infection were the mesentery and the muscle. Metacercariae of I. dimorphum were collected in muscles of a specimen of H. malabaricus, with 0.96% of prevalence, intensity of infection of 2 parasites and 0.02 of abundance. New morphological data of external and internal structures are presented. This is the first record of metacercariae of C. sorbens and I. dimorphum in Amazonian fish.

Some unfavourable effects of malnutrition of the host on Schistosoma mansoni worm biology and structure have been reported based upon brigthfield microscopy. This paper aims to study by morphometric techniques, some morphological parameters in male and female adult worms recovered from undernourished albino mice in comparison with parasites recovered from well-fed infected mice. Undernourished animals were fed a multideficient and essentially low protein diet (RBD diet) and compared to well-fed control mice fed with the commercial diet NUVILAB. Seventy-five days post-infection with 80 cercarie (BL strain) animals were sacrificed. All adult worms were fixed in 10% formalin and stained with carmine chloride. One hundred male and 60 female specimens from each group (undernourished and control) were examined using an image system analysis Leica Quantimet 500C and the Sigma Scan Measurement System. The following morphometrical parameters were studied: body length and width, oral and ventral suckers, number and area of testicular lobes, length and width of ovary and uterine egg. For statistical analysis, the Student's t test for unpaired samples was applied. Significant differences (p < 0.05) were detected in body length and width, in parameters of suckers, uterine egg width, ovary length and area of testicular lobes, with lower values for specimens from undernourished mice. The nutritional status of the host has negative influence on S. mansoni adult worms, probably through unavailability of essential nutrients to the parasites.