No abstract

This study evaluated the in vitro and in vivo antiparasitic efficacy of formalin against Dawestrema cycloancistrium, the effects on the physiological response of Arapaima gigas and the residual action on fish muscle after 96 h of exposure. As regards the in vitro assay, 0, 22, 44, 66, 88, 110, 330, 660 and 880 mg L − 1 formalin were tested. After 1 h of exposure to 660 and 880 mg L − 1 formalin, there was a 100% mortality of D. cycloancistrium as well as after 2 h of exposure at 330 and 110 mg L − 1 and 3 h of exposure at 44, 66 and 88 mg L − 1. Concerning the in vivo test, when fish were exposed to formalin at 0, 220, 330, 440 and 550 mg L − 1 , there was 100% survival at all concentrations and exposure times evaluated. Baths of 1 h with 440 and 550 mg L − 1 formalin showed 93.3% and 99.3% efficacy respectively. However, the baths of 12 h with 55 and 66 mg L − 1 formalin had the efficacy of 44.5% and 55.5% respectively. In 1 h baths with 220, 330, 440 and 550 mg L − 1 formalin, hematocrit, hemoglobin, number of total erythrocytes, mean corpuscular volume, mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, plasma glucose levels, cortisol, total proteins, chloride, calcium, sodium, potassium and magnesium of the fish presented no differences in relation to the control values. However, in baths of 12 h with 33, 44, 55 and 66 mg L − 1 formalin, there was a decrease in hematocrit, plasma levels of calcium and chloride, and increased levels of glucose and cortisol, depending on the concentration of formalin used. In the fish muscle, the formalin residue decreased after 96 h in all concentrations and periods evaluated, returning to values close to the control ones. The results indicate that formalin had its efficacy successfully proved in the treatment against D. cycloancistrium at higher concentrations such as 440 and 550 mg L − 1 formalin and shorter exposure time (1 h) without compromising fish homeostasis and consumer food safety. Statement of relevance: The manuscript represents original research on use of formalin in vitro and in vivo for treating infection by monogenoidean Dawestrema cycloancistrium in Arapaima gigas, the giant fish from Amazon. In the fish, muscle the residue levels of formalin after exposure was also investigated. Formalin have efficacy in the treatment against D. cycloancistrium at higher concentrations (440 and 550 mg.L − 1) of formalin and shorter exposure time (1 h) and without compromising A. gigas homeostasis and consumer food safety.

Achatina fulica or "giant African snail" is an exotic species, considered to be one of the world's hundred most invasive species, causing serious environmental damages. In the present study we report, for the first time, the occurrence of Aelurostrongylus abstrusus infecting A. fulica in the Amazon region. This nematode is described parasitizing mainly the pulmonary system of felines, which causes "aelurostrongilose", also known as feline cardio-pulmonary strongyloidosis. New morphometric data of third stage larvae are presented herein. The present study demonstrated that 40% of all the snails were infected by A. abstrusus. Achatina fulica specimens were collected from three different areas in Manaus namely: rural; east and west areas. The east area presents the highest prevalence of 80%. The large number of A. fulica found in inhabited areas increases the chances of emergent zoonoses, which highlights the need of further studies so as to better control this disease. Keywords: Giant african snail; Parasitology; Nematode larvae; Helminth; Central Amazon. Ocorrência de Aelurostrongylus abstrusus (Railliet, 1898) (Nematoda:Metastrongylidae) infectando o Achatina (Lissachatina) fulica Bowdich, 1822 (Mollusca: Gastropoda) na região amazônica resumo Achatina fulica ou "caramujo africano" é uma espécie exótica, considerada uma das cem piores espécies invasoras do mundo, causando sérios danos ambientais. No presente estudo foi registrado, pela primeira vez, a ocorrência do Aelurostrongylus abstrusus infectando o A. fulica na região amazônica. Esse nematóide é descrito parasitando principalmente o sistema pulmonar de felinos, causando a "aelurostrongilose", também conhecida como estrongiloidose cardio-pulmonar felina. Novos dados morfométricos de larvas de terceiro estágio são apresentados. Dos 45 caramujos coletados, 40% estavam infectados por larvas de A. abstrusus. Especimens de Achatina fulica foram coletados em três áreas da cidade de Manaus: rural, leste e oeste. A zona leste apresentou a maior prevalência de 80%. O grande número de A. fulica encontrado em áreas habitadas aumenta as chances de ocorrência de zoonoses emergentes e destaca a necessidade de mais estudos para o melhor controle da doença.

Third-stage larvae (L 3 ) of Hysterothylacium sp. were collected by the first time in juveniles of pirarucu Arapaima gigas farmed in the Rio Preto da Eva, Amazonas state. Ninety-eight (98) out of 100 examined fish showed to be parasitized. Five hundred and ninety larvae of Hysterothylacium sp. were collected from the intestines, stomach and pyloric caeca. The mean intensity of parasite indexes was 6.02 (±5.75) ranging from 1 to 40 larvae per host and the mean abundance was 5.9 (±5.76). The A. gigas is the new host record for larvae of Hysterothylacium sp. in Brazil, and this is the first record of larvae of Hysterothylacium (Nematoda: Anisakidae) with zoonotic potential in the pirarucu from South America.

This study aimed to determine the lethal concentration and the structural and ultra-structural effects caused by the formalin exposure on juveniles of Arapaima gigas. Ninety fish (60.1± 2.5g and 20.2±0.9cm) were exposed to 0, 22, 44, 66, 88 and 110mg L-1 in order to determine the lethal concentration (LC50-96h) that was 36.4mg L-1 of formalin. Sublethal effects were evaluated using histopathological analysis on the gills and assessment of behavioral alterations and clinical signs. The LC50 of formalin for 24, 48 and 72h was 88.3, 64.7 and 56.8mg L-1 respectively. Clinical signs and behavioral changes were found: erratic swimming, lethargy, crowding on the water surface, loss of hydrodynamic equilibrium, spasms and agonistic confrontation, which were observed only at 88 and 110mg L-1. The histological alteration index (HAI) showed that 66, 88 and 100mg L-1 presented significant difference (p<0.05) in relation to unexposed fish, indicating that moderate damage to the gills of fish exposed to formalin had occurred. The mean values of alteration (MVA) for 22, 44, 66, 88 and 110mg L-1 were 1.14, 1.29, 1.51, 1.53 and 1.60 respectively, and differences in this index were only observed with 110 mgL-1 of formalin. It is therefore possible to conclude that sublethal concentrations of formalin (22.0mg L-1) did not compromise the health of juveniles of A. gigas. Finally, concentrations greater than to LC50-96h may be carefully used for short-term exposure, since the MVA for all concentrations tested only indicated localized lesions that did not compromise gills functionality of exposed fish.

ResumoOs ciclídeos, peixes economicamente importantes na região, foram coletados no médio rio Negro (Cichla orinocensis, C. monoculus e C. temensis) e na iIlha da Marchantaria (C. monoculus), no Amazonas e em três açudes do Piauí (C. kelberi). Para verificar a ocorrência de parasitas as brânquias, narinas e intestino foram removidos e observados em microscópio esteroscópio, a boca a olho nu. Os parasitas encontrados foram retirados e armazenados em álcool 70% para posterior identificação. Dos 96 espécimes analisados provenientes do rio Negro 51 (52%) estavam parasitadas; dos 34 da ilha da Marchantaria 16 (47%) e dos 50 dos açudes do Piauí, apenas dois (4%). Nos peixes coletados no Amazonas, as brânquias estavam parasitadas por Ergailus coatiarus, Argulus amazonicus, Acusicola tucunarense e a boca por Braga cichlae, enquanto que os peixes do Piauí não apresentaram parasitas branquiais, mas registrou-se a ocorrência do nematóide Procamallanus (Spirocamallanus) inopinatus, parasita intestinal.Palavras-chave: Cichla spp., Amazonas, Piauí, parasitas. AbstractThe cichlids, economically important fish specie in the region, were collected along the Negro River (Cichla orinocensis, C. monoculus e C. temensis) and in the Marchantaria Island (C. monoculus) Amazon State and in three reservoirs localized in the Piauí State. In order to verify the occurrence of parasites, gills, nostrils and the intestine were removed and observed by stereomicroscope and the mouth by naked eyes. The observed parasites were isolated and conserved in 70% ethanol for posterior identification. From 96 specimens collected in Negro River, 51 specimens (52%) were parasitized. In the Marchantaria Island from 34 specimens collected, 16 (47%) showed the presence of parasites, and from 50 specimens collected in the reservoirs only 2 (4%) were parasitized. In fishes collected in the Amazon State, the grill was parasitized by Ergailus coatiarus, Argulus amazonicus, Acusicola tucunarense and the mouth by Braga cichlae, whereas the species collected in the Piauí State did not show the presence of parasites in the grill, but the occurrence of Procamallanus (Spirocamallanus) inopinatus an intestinal nematode parasite.

O Arapaima gigas (Schinz, 1822) é um peixe que habita os rios amazônicos, de suma importância ecológica, e que por apresentar um elevado valor comercial e sobrepesca, corre risco de extinção. Além disto, é atrativo para a piscicultura devido ao bom rendimento zootécnico. Um dos entraves para a produção do pirarucu em cultivo são as doenças parasitarias que intervém na quantidade e qualidade dos peixes cultivados. Os endoparasitas, como os nematodos, alimentam-se de nutrientes já processados pelo hospedeiro e podem causar alterações intestinais, além de levar o peixe à subnutrição e a um estado anemiante. No presente estudo foram avaliadas as alterações histopatológicas causadas no intestino de A. gigas, pelo nematódeo Spirocamallanus inopinatus (Travassos, 1929). Foram processados histologicamente os intestinos de seis espécimes hospedeiros, dos quais três estavam parasitados pelo nematódeo. As alterações encontradas foram: áreas de necroses focais, descamações, infiltrado inflamatório, citólise e formação de capsulas fibrosas. Este é o primeiro estudo que reporta as lesões teciduais no intestino de A. gigas na presença do nematódeo S. inopinatus.

O paradigma empírico-indutivista da Ciência foi importante para que a humanidade pudesse experimentar uma rápida expansão dos seus horizontes do conhecimento. Com o passar do tempo, este modo de conceber o fazer científico conduziu os indivíduos a estabelecerem crenças equivocadas e simplistas sobre o fazer científico e o papel da Ciência. Nessa perspectiva, a superação de visões distorcidas de Ciência por parte dos indivíduos sociais perpassa pela compreensão, análise e reflexão crítica das condicionantes externas que guiaram o desenvolvimento científico e tecnológico até aqui. Nessa perspectiva, este manuscrito almeja, por meio de um estudo teórico e reflexivo, conjecturar sobre histórico, fundamentos e a evolução do conhecimento científico. Iniciaremos a nossa caminhada pela Idade Moderna, onde buscaremos evidenciar as características e diferenças entre as correntes filosóficas dominantes que se sucederam até meados do século XIX. A seguir, adentraremos o século XX, onde passaremos a destacar as contribuições de alguns dos principais filósofos contemporâneos que, por meio de suas teorias, buscavam estabelecer uma visão mais crítica acerca da produção do conhecimento científico e do papel da Ciência. Por fim, abordaremos as contribuições de uma possível associação entre a educação CTS e a História e a Filosofia da Ciência (HFC), como abordagem para o ensino de ciências capaz de contemplar a dimensão histórica e filosófica do conhecimento científico, considerando as suas implicações sociais, culturais, tecnológicas e políticas.