Parasitic lesions in fish in the Federal District, Brazil

Brazil has a vast territory and favorable climatic conditions that allow the cultivation of freshwater fish. The intensification of the productive system can cause an imbalance in the aquatic environment as a result of poor water quality, nutritional deficiencies and infectious or parasitic diseases. The laboratory diagnosis and the determination of the prevalence of the main lesions, which occur in a certain region, help to guide towards the etiological diagnosis. This study aimed to describe the main parasitic lesions in fish in the routine at the Veterinary Pathology Laboratory of the Universidade de Brasília (UnB). All records of fish with parasitic lesions were recovered. Those cases in which there was an intralesional parasite and which presented lesions compatible with the parasite were included. The screening of ectoparasites was done by scraping the superficial mucus from the gills and skin. Organ sections were routinely processed for histopathologyand stained with hematoxylin-eosin (HE). In some records, parasitological identification was carried. The information was divided into the species of the affected fish, epidemiology of the outbreak (water quality, temperature, type of breeding), lesion distribution, etiology and macroscopic and microscopic changes. The resulting data was organized in absolute frequency and percentage. In this study, 22 cases were counted, between individual deaths and outbreaks, totaling 83 necropsied teleost fish. Inflammatory changes of parasitic origin were seen in 13/22 (59%) of the cases had lesions of parasitic origin. Skin lesions and gills were the most relevant. Macroscopically, red areas or spots of hyperemia or hemorrhage on the body surface were the most prevalent findings. Under microscopy, proliferative gill inflammation was the most relevant diagnosis. Pscinoodinium pilullare (Dinoflagellida), Ichthyophthirius multifiliis (Ciliophora), and monogenetic worms (Monogenea) were the main parasites found. Trichodina sp. (Ciliophora), Ichtyobodo sp. (Kinetoplastida), Amoebas, and Chilodonella sp. (Ciliophora), were seen in fewer numbers. An unusual case suggestive of parasitism by Eustrongylides sp. (Nematoda), in a pirá-brasília (Simpsonichthys boitonei), specimen has been recorded. The diagnoses were based on epidemiology, anatomopathological and parasitological findings. The most frequent and significantly lethal lesion in the study was proliferative and / or hyperplastic branchitis. Proliferative branchitis with lamellar epithelial hyperplasia (LEH) is a response to some type of chemical or mechanical injury to the gill epithelium in order to protect the capillaries from further damage or microbial penetration. However, it also increases the diffusion distance between capillaries and the environment and, therefore, hinders breathing, excretory and osmoregulatory functions. Protozoan infections and monogenetic worms in general generated LEH and skin lesions of mechanical origin. Secondary bacterial infection, were observed in this parasitosis determining the cause of death of the fish. Its pathogenicity comes from the lesions caused by the colonization and histophagy of the epithelial surfaces, mainly gills and skin, causing epithelial proliferation, lamellar cell fusion, epithelial cell degeneration and necrosis forming several ulcers in the epithelium after the release of mature trophies. The pathogenesis of parasitism by Eustrongylides spp. is considerable when there is a large quantity of these larvae that can cause intestinal obstruction, rupture and compression of viscera, of greater importance in small fish. The main parasites of necropsied fish were protozoa and monogenetic worms, which mainly cause branquitis and dermatitis in varying grades.(AU)

Peixe Encravado na Árvore Respiratória de Uma Criança: Um Caso Invulgar / Ingrown Fish in a Child's Respiratory Tree: An Unusual Case

Corpos estranhos nos orifícios naturais da cabeça e pescoço são de ocorrência comum na prática clínica, sobre¬tudo nas urgências de otorrinolaringologia. Entretanto, um peixe inteiro nas vias aéreas é uma ocorrência relati¬vamente invulgar. Assim, nesta comunicação, descreve-se uma peça anatómica das vias respiratórias de uma criança que apresenta um pequeno peixe encravado e que se encontra exposta no Museu de Anatomia do De¬partamento de Ciências Morfológicas da Faculdade de Medicina da Universidade Eduardo Mondlane. Esta peça representa um importante exemplo anatómico no processo de ensino-aprendizagem das causas de asfixia sobre¬tudo em crianças que se dedicam à pesca e/ou gostam de fazer mergulhos nos rios ou nos mares.

Foreign bodies in the natural orifices of the head and neck are a common occurrence in clinical practice, especially in urgent cases of otolaryngology. However, a whole fish in the airways is a relatively unusual occurrence. Thus, in this communication, an anatomical piece of the respiratory tract of a child that presents a small ingrown fish is described in the Museum of Anatomy of the Department of Morphological Sciences of the Faculty of Medicine of the Eduardo Mondlane University. This piece represents an important anatomical specimen in the teaching-learning process of the causes of asphyxia, especially in children who dedicate themselves to fishing and / or like to do dives in rivers or seas.

A Comparative Perspective on Brain Regeneration in Amphibians and Teleost Fish.

Regeneration of lost cells in the central nervous system, especially the brain, is present to varying degrees in different species. In mammals, neuronal cell death often leads to glial cell hypertrophy, restricted proliferation, and formation of a gliotic scar, which prevents neuronal regeneration. Conversely, amphibians such as frogs and salamanders and teleost fish possess the astonishing capacity to regenerate lost cells in several regions of their brains. While frogs lose their regenerative abilities after metamorphosis, teleost fish and salamanders are known to possess regenerative competence even throughout adulthood. In the last decades, substantial progress has been made in our understanding of the cellular and molecular mechanisms of brain regeneration in amphibians and fish. But how similar are the means of brain regeneration in these different species? In this review, we provide an overview of common and distinct aspects of brain regeneration in frog, salamander, and teleost fish species: from the origin of regenerated cells to the functional recovery of behaviors.

Injury-mediated decrease in locomotor performance increases predation risk in schooling fish.

The costs and benefits of group living often depend on the spatial position of individuals within groups and the ability of individuals to occupy preferred positions. For example, models of predation events for moving prey groups predict higher mortality risk for individuals at the periphery and front of groups. We investigated these predictions in sardine (Sardinella aurita) schools under attack from group hunting sailfish (Istiophorus platypterus) in the open ocean. Sailfish approached sardine schools about equally often from the front and rear, but prior to attack there was a chasing period in which sardines attempted to swim away from the predator. Consequently, all sailfish attacks were directed at the rear and peripheral positions of the school, resulting in higher predation risk for individuals at these positions. During attacks, sailfish slash at sardines with their bill causing prey injury including scale removal and tissue damage. Sardines injured in previous attacks were more often found in the rear half of the school than in the front half. Moreover, injured fish had lower tail-beat frequencies and lagged behind uninjured fish. Injuries inflicted by sailfish bills may, therefore, hinder prey swimming speed and drive spatial sorting in prey schools through passive self-assortment. We found only partial support for the theoretical predictions from current predator-prey models, highlighting the importance of incorporating more realistic predator-prey dynamics into these models.This article is part of the themed issue 'Physiological determinants of social behaviour in animals'.

Use of navigation channels by Lake Sturgeon: Does channelization increase vulnerability of fish to ship strikes?

Channelization for navigation and flood control has altered the hydrology and bathymetry of many large rivers with unknown consequences for fish species that undergo riverine migrations. In this study, we investigated whether altered flow distributions and bathymetry associated with channelization attracted migrating Lake Sturgeon (Acipenser fulvescens) into commercial navigation channels, potentially increasing their exposure to ship strikes. To address this question, we quantified and compared Lake Sturgeon selection for navigation channels vs. alternative pathways in two multi-channel rivers differentially affected by channelization, but free of barriers to sturgeon movement. Acoustic telemetry was used to quantify Lake Sturgeon movements. Under the assumption that Lake Sturgeon navigate by following primary flow paths, acoustic-tagged Lake Sturgeon in the more-channelized lower Detroit River were expected to choose navigation channels over alternative pathways and to exhibit greater selection for navigation channels than conspecifics in the less-channelized lower St. Clair River. Consistent with these predictions, acoustic-tagged Lake Sturgeon in the more-channelized lower Detroit River selected the higher-flow and deeper navigation channels over alternative migration pathways, whereas in the less-channelized lower St. Clair River, individuals primarily used pathways alternative to navigation channels. Lake Sturgeon selection for navigation channels as migratory pathways also was significantly higher in the more-channelized lower Detroit River than in the less-channelized lower St. Clair River. We speculated that use of navigation channels over alternative pathways would increase the spatial overlap of commercial vessels and migrating Lake Sturgeon, potentially enhancing their vulnerability to ship strikes. Results of our study thus demonstrated an association between channelization and the path use of migrating Lake Sturgeon that could prove important for predicting sturgeon-vessel interactions in navigable rivers as well as for understanding how fish interact with their habitat in landscapes altered by human activity.

A comparison of hematology, plasma chemistry, and injuries in Hickory shad (Alosa mediocris) captured by electrofishing or angling during a spawning run.

BACKGROUND: Declines in Hickory shad (Alosa mediocris) populations in Chesapeake Bay have prompted efforts at captive propagation of wild broodfish for stock enhancement and research. OBJECTIVE: The objectives of this study were to evaluate injuries sustained, and immediate and delayed (24 hours) effects on blood variables related to 2 fish capturing methods (electrofishing [EF] and angling). METHODS: Blood specimens were collected from fish immediately following capture by EF and angling (n = 40 per sex and capture method) from the Susquehanna River (MD, USA). Additional fish (n = 25 per sex and capture method) were collected on the same day, placed in holding tanks and bled 24 hours following capture. Blood data that were non-Gaussian in distribution were transformed (Box-Cox), and effects of sex, method of capture, and holding time were tested using ANOVA with general linear models. Fish were evaluated for injuries by necropsy and radiography. RESULTS: Sex-specific differences were observed for RBC, HGB, PCV, MCH, MCHC, total proteins (TP), globulins, glucose, calcium, AST, CK, and lactate, while RBC, HGB, PCV, MCV, MCH, MCHC, TP, albumin, globulins, glucose, potassium, sodium, AST, CK, and lactate differed significantly by fish capturing method. Electrofishing may have induced greater disruption in blood variables, but mortality (4%) was not significantly different compared to angling. CONCLUSIONS: Electrofishing for Hickory shad using a constant DC voltage resulted in numerous hematologic and biochemical changes, with no additional injuries or deaths compared to angling. Capture method must be considered when evaluating fish condition, and blood variables should be partitioned by sex during spawning season.

Effects of Exposure to the Sound from Seismic Airguns on Pallid Sturgeon and Paddlefish.

This study examined the effects of exposure to a single acoustic pulse from a seismic airgun array on caged endangered pallid sturgeon (Scaphirhynchus albus) and on paddlefish (Polyodon spathula) in Lake Sakakawea (North Dakota, USA). The experiment was designed to detect the onset of physiological responses including minor to mortal injuries. Experimental fish were held in cages as close as 1 to 3 m from the guns where peak negative sound pressure levels (Peak- SPL) reached 231 dB re 1 µPa (205 dB re 1 µPa2·s sound exposure level [SEL]). Additional cages were placed at greater distances in an attempt to develop a dose-response relationship. Treatment and control fish were then monitored for seven days, euthanized, and necropsied to determine injuries. Necropsy results indicated that the probability of delayed mortality associated with pulse pressure following the seven day monitoring period was the same for exposed and control fish of both species. Exposure to a single pulse from a small air gun array (10,160 cm3) was not lethal for pallid sturgeon and paddlefish. However, the risks from exposure to multiple sounds and to sound exposure levels that exceed those reported here remain to be examined.

Report of 15 injuries caused by lionfish (pterois volitans) in aquarists in Brazil: a critical assessment of the severity of envenomations

Lionfish are venomous fish that belong to the Scorpaenidae family. Individuals of this family and those of the Synanceiidae family comprise most of the existing venomous fish in the world. Lionfish are originally found in the Indo-Pacific, but they have received special attention in the last years for their dissemination in the Atlantic Ocean, with the emergence of large populations in the USA, Caribbean and South America. Because of its beauty, this fish has always been present in private and commercial aquariums around the world. Herein, we describe 15 envenomations in aquarists registered in a period of eighteen years (1997-2014). The stings caused excruciating pain and marked inflammation, with local erythema, edema, heat, paleness and cyanosis. In one case, it was possible to observe vesicles and blisters. There were no skin necroses or marked systemic manifestations. We discuss the possible coming of the fish to South America and the circumstances and clinical impact of the envenomations.(AU)

Surgical repair of mandibular symphyseal fractures in three silver arowana (Osteoglossum bicirrhosum) using interfragmentary wire.

Three silver arowana (Osteoglossum bicirrhosum) were presented with unstable fractures of the mandibular symphyses. Surgical repair was performed to reduce and stabilize the fractures using interfragmentary wire. The fish returned to light feeding at 2 days and normal feeding at 5 days postsurgery. The wires were removed at 6 wk postsurgery with good alignment of the mandibular symphyses and stable fracture sites. There had been no further complications at the time of writing 18 wk postsurgery.

Tempo de indução e recuperação à anestesia do eugenol para patinga (Piaractus brachypomus) / Eugenol anesthesia induction and recovery time for (Piaractus brachypomus) / Tiempo de inducción y recuperación a la anestesia de eugenol en morocoto (Piaractus brachypomus)

Este trabalho tem como finalidade avaliar o uso do eugenol como anestésico para a patinga (Piaractus brachypomus), mensurando o tempo de indução à anestesia e recuperação. Foram mensurados o tempo de indução e recuperação à anestesia em diferentes concentrações de eugenol e glicose plasmática. Os resultados foram analisados segundo um delineamento inteiramente casualisado (DIC) com seis tratamentos (controle, 25, 35, 50, 75 e 150 L-1 de eugenol) e dez repeti- ções cada. As análises de variância (ANOVA) e as médias foram comparadas pelo teste de Tukey. Concentrações acima de 150mg.L-¹ apresentaram mortalidade de 100% da população. Os tempos de indução à anestesia profunda registrada para as concentrações de 50 e 75mg L-1 foram que apresentaram menores tempos de sedação. Observa-se que o tempo de recuperação patinganas doses de 50mg.L-¹ foi de 93 seg. a dose de 25mg.L-1 de eugenol foi a única que obteve diminuição nos níveis de glicose plasmática, o que pode ser um indício de utilização de pequenas doses deste no manejo da patinga. Conclui-se que o eugenol é um anestésico adequado para juvenis patinga com peso de 256,6±73,18g. Podendo utilizado em concentrações de 50mg. L-1 de eugenol...

This paper aims to standardize the use of eugenol as an anesthetic for the patinga (Piaractus brachypomus), measuring the time for anesthesia induction and recovery. Induction and recovery times to anesthesia were measured in different concentrations of eugenol and plasma glucose. The results were analyzed according to a completely randomized design (CRD) with six treatments (control, 25, 35, 50, 75 and 150 L-1 of eugenol) and ten repetitions each. The analysis of variance (ANOVA) and averages were compared by Tukey test. Concentrations above 150 mg.L-¹ presented 100% mortality of the population. The deep anesthesia induction times recorded for concentrations of 50 and 75 mg L-1 were the ones presenting the shortest sedation times. It can be observed that the patinga recovery time for 50mg.L-1 doses was 93 seconds. The 25mg.L-1 dose of eugenol was the only dose obtaining a decrease in plasma glucose levels which can be an indication to the use of small doses for the management of patinga. It can also be concluded that eugenol is a suitable anesthetic for patinga weighing 256.6 ± 73.18 g, and it can be used at concentrations of 50mg. L-1 eugenol...

Este estudio ha tenido como objetivo evaluar el uso de eugenol como anestésico para el morocoto Piaractus brachypomus, midiendo el tiempo de inducción a la anestesia y recuperación. Fueron medidos el tiempo de inducción y recuperación a la anestesia en diferentes concentraciones de eugenol y la glucosa plasmática. Los resultados fueron analizados según un delineamiento enteramente casualizado con seis tratamientos (control, 25, 35, 50, 75 y 150 L-1 de eugenol) y 10 (diez) repeticiones cada uno. El análisis de varianza (ANOVA) y los promedios se compararon por prueba Tukey. Concentraciones superiores a 150 mg.L-¹ presentaron mortalidad de 100% de la población. Los tiempos de inducción a la anestesia profunda registrada para las concentraciones de 50 y 75 mg L-1 fueron las que presentaron menores tiempos de sedación. Se observa que el tiempo de recuperación de morocotos con dosis de 50 mg.L-1 fue de 93 seg. La dosis de 25 mg.L-1 de eugenol fue la única que obtuvo disminución en los niveles de glucosa plasmática, lo que puede ser un indicio de utilización de dosis pequeñas de esto en manejos de morocotos. Se concluye que el eugenol es un anestésico adecuado para morocotos juveniles con peso de 256.6 ± 73, 18 g, pudiendo ser utilizado en concentraciones de 50 mg. L-1 de eugenol...

Injuries from non-retention in gillnet fisheries suppress reproductive maturation in escaped fish.

Exploitation of fisheries resources has unintended consequences, not only in the bycatch and discard of non-target organisms, but also in damage to targeted fish that are injured by gear but not landed (non-retention). Delayed mortality due to non-retention represents lost reproductive potential in exploited stocks, while not contributing to harvest. Our study examined the physiological mechanisms by which delayed mortality occurs and the extent to which injuries related to disentanglement from commercial gear compromise reproductive success in spawning stocks of Pacific salmon (Oncorhynchus spp.). We found evidence for elevated stress in fish injured via non-retention in gillnet fisheries. Plasma cortisol levels correlated with the severity of disentanglement injury and were elevated in fish that developed infections related to disentanglement injuries. We also analyzed sex steroid concentrations in females (estradiol-17ß and 17,20ß-dihydroxy-4-pregnen-3-one) to determine whether non-retention impairs reproductive potential in escaped individuals. We demonstrate evidence for delayed or inhibited maturation in fish with disentanglement injuries. These findings have important implications for effective conservation and management of exploited fish stocks and suggest means to improve spawning success in such stocks if retention in commercial fisheries is improved and incidental mortality reduced.

Lesión complicada por picadura del pez león (Pterois volitans) / Complicated lesions after the sting of the Lionfish (Pterois volitans)

Se presenta el caso de un buzo profesional, de la raza blanca, de 29 años de edad, con antecedentes patológicos personales de obesidad exógena grado I, quien acude al hospital con lesión complicada por picadura del pez león (Pterois volitans) en el miembro inferior izquierdo (cara anteromedial de la pierna), de 21 días de evolución, durante una actividad de corte y soldadura subacuática, en aguas turbias a una profundidad entre 4 y 5 m. Se refieren los síntomas siguientes: dolor intenso con irradiación e hipoestesia, signos de celulitis y linfangitis de evolución tórpida hacia la necrosis e infección de la herida por la aplicación incorrecta de la terapéutica médica inicial. Se indicó tratamiento médico con antibioticoterapia, analgésicos, antinflamatorios y antihistamínicos por vía oral y tratamiento quirúrgico con necrectomía, curas locales y cierre de la herida por colgajo; se adjuntó la oxigenación hiperbárica para la estimulación de la reparación, defensa y cicatrización de los tejidos lesionados. El conocimiento acerca del tema permite actuar con precaución ante las manifestaciones clínicas y sus complicaciones. La aplicación de la oxigenación hiperbárica posibilita disminuir el tiempo de evolución y la reincorporación rápida del paciente a su laborAU)

Twenty-nine years old white professional diver with personal pathological antecedents of Type I exogenous obesity who presents to the hospital with a complicated bite of lionfish (Pterois volitans) in the left lower limb (anteromedial part of the leg) of 21 days evolution. The patient was bitten during an underwater activity of cutting and welding in muddy waters at a depth between 4 and 5 meters. He reports the following symptoms: acute pain with irradiation and hypoesthesia, signs of cellulitis and lymphangitis of torpid evolution towards the necrosis and infection of the wound as a result of an incorrect initial medical therapy. Medical treatment with antibiotics, analgesics, antinflammatories and antihistamines per mouth was indicated and surgical treatment with Necrectomy, local cures and flap for wound closure was employed. Hyperbaric oxygenation for the stimulation of the repair, defense and cicatrisation of the injured tissues was included. The knowledge about this topic allows acting with caution considering the clinical manifestations and its complications. The use of hyperbaric oxygenation makes the diminishment of the time of evolution and the return of the patient to work possible(AU)

Injuries and deformities in fish: their potential impacts upon aquacultural production and welfare.

Fish can be the recipients of numerous injuries that are potentially deleterious to aquacultural production performance and welfare. This review will employ a systematic approach that classifies injuries in relation to specific anatomical areas of the fish and will evaluate the effects of injury upon production and welfare. The selected areas include the (1) mouth, (2) eye, (3) epidermis and (4) fins. These areas cover a large number of external anatomical features that can be injured during aquacultural procedures and husbandry practices. In particular, these injuries can be diagnosed on live fish, in a farm environment. For each anatomical feature, this review addresses (a) its structure and function and (b) defines key injuries that can affect the fish from a production and a welfare perspective. Particular attention is then given to (c) defining known and potential aquacultural risk factors before (d) identifying and outlining potential short- and long-term farming practices and mitigation strategies to reduce the incidence and prevalence of these injuries. The review then concludes with an analysis of potential synergies between risk factors the type of injury, in addition to identifying potential synergies in mitigation strategies. The paper covers both aquaculture and capture-based aquaculture.

Modelling of effects due to chronic exposure of a fish population to ionizing radiation.

A dynamic model was developed for description of radiation effects in an isolated fish population chronically exposed at different dose rates. The induced effects were predicted based on damage created by the radiation, recovery by means of repair mechanisms, and natural growth of the population. Three types of radiation effects (umbrella endpoints) were simulated--decrease of population size, decrease of reproductive capacity, and effects on the morbidity of the population. The influence of ecological interactions on the irradiated fish population was simulated using the combined action of radiation and parasite infestation as an example (ecological interaction "host-parasite"). The model calculations demonstrate that influence of ecological interactions can considerably aggravate the effects of radiation to an exposed population. It was concluded that development of standards for wildlife protection against ionizing radiation requires consideration of possible ecological interactions and to take into account the ecological effects of radiation.

Parasitic castration, growth, and sex steroids in the freshwater bonefish Cyphocharax gilbert (Curimatidae) infested by Riggia paranensis (Cymothoidea)

Cyphocharax gilbert shows parasitic castration when infested by the crustacean Riggia paranensis, being unable to reproduce. Fish were sampled in the middle rio Itabapoana, Brazil, to study the prevalence of parasitism, growth, and sex steroid concentrations, considering the body size, sex, and reproductive condition of specimens. Most of the fish analyzed were infested (56.0 percent). The presence of two lines on the scales was more frequent among infested fish (22.0 percent) than among fish without parasites (12.0 percent for females and 10.0 percent for males). The occurrence of three lines on the scales was rare (3.5 percent among infested and 2.0 percent among females without parasites). These results suggest that growth of the host is faster than that of non infested fish. The serum concentrations of sex steroids from fish without parasites varied at different gonadal development stages (17 beta-estradiol: 60.0 to 976.7 pg/ml; total testosterone: 220.0 to 3,887.7 pg/ml). All infested fish had lower levels of the two sex steroids and undeveloped gonads. Sex steroids levels in infested females were close to those in females at post-spawning stages. Total testosterone concentrations of infested males were below those of males at early gonadal maturation stage. These results suggest that R. paranensis reduces the reproductive capacity of C. gilbert by affecting the host endocrine system

Cyphocharax gilbert exibe castração parasitária quando está infestado pelo crustáceo Riggia paranensis, estando impossibilitado de reproduzir. Os peixes foram coletados no trecho médio do rio Itabapoana, Brasil, para analisar a prevalência do parasitismo, quantificar crescimento e as concentrações de esteróides sexuais, considerando o tamanho do corpo, o sexo e a condição reprodutiva dos espécimes. A maioria dos peixes analisados estava infestada (56,0 por cento). A presença de duas linhas em escamas foi mais freqüente entre os peixes infestados (22,0 por cento) que entre os peixes não infestados (12,0 por cento para as fêmeas e 10,0 por cento para os machos). A presença de três linhas na escama foi rara (3,5 por cento entre os peixes infestados e 2,0 por cento entre as fêmeas não infestadas). Estes resultados sugerem que o crescimento no hospeideiro pode ser mais rapido que no peixes não parasitados. As concentrações de esteróides sexuais no soro dos peixes não infestados variaram entre os diferentes estágios reprodutivos (17 beta-estradiol: 60,0 a 976,7 pg/ml; total testosterona: 220,0 a 3.887,7 pg/ml). Todos os peixes infestados apresentaram baixos níveis dos dois hormônios esteroidais e ausência de desenvolvimento gonadal. Os níveis de esteróides sexuais nas fêmeas infestadas foram próximos aos níveis encontrados nas fêmeas pós-desovadas. A concentração de testosterona encontrada nos machos infestados foi inferior àquela obtida nos machos que estavam iniciando o desenvolvimento gonadal. Estes resultados sugerem que R. paranensis impede a reprodução de C. gilbert, afetando o sistema endócrino do hospedeiro

Emergency and critical care of fish.

Most fish emergencies are the result of inappropriate environmental conditions and primary or secondary infectious disease or trauma. The immediate response should be to increase aeration, provide suitable water, and decrease stressors. A thorough history, evaluation of the fish and their environment, and some rapid diagnostic tests (particularly direct and stained cytology) often provide the information needed to make a diagnosis and render appropriate treatment. When cohorts are at risk and the patient is unlikely to recover, euthanasia and necropsy are recommended to reach a definitive diagnosis. Some common emergencies include ammonia and nitrite toxicity; low dissolved oxygen; copper and chlorine toxicity; gas supersaturation; and certain bacterial, protozoal, and viral diseases.