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)

Copper acclimation in juvenile fathead minnows: is a cycle of branchial damage and repair necessary?

Fathead minnows exposed to sublethal Cu concentrations may undergo branchial damage followed by repair, and may also develop enhanced Cu tolerance. The primary objective of this study was to determine whether the cycle of damage and repair was necessary for the development of enhanced Cu tolerance. Inferences regarding damage and repair were made from changes in the whole body Na(+) of juvenile (0.5 g) fathead minnows (Pimephales promelas). Two experiments were conducted in which juvenile minnows were exposed to various sublethal Cu concentrations for 16 d. In the first experiment, fish were exposed to one of four different Cu concentrations (0, 73, 118, 189 microg/L Cu) then challenged with an 8-d exposure at 302 microg Cu/L. Only the fish exposed to the highest Cu dose experienced enhanced Cu tolerance relative to the other three doses. In the second experiment, whole body Na(+) was monitored in fish exposed to one of five different Cu exposures (0, 70, 127, 202, 289 microg/L Cu). Fish exposed to 70 microg/L Cu did not experience a significant decline in whole body Na(+) at any point during the 16-d exposure period. The reduction in whole body Na(+) was short lived and moderate (17%) in the fish exposed to 127 microg/L Cu, but more severe (>30%) and longer lasting in the fish exposed to 202 microg/L Cu. At 289 microg/L Cu, the fish experienced irreversible reductions in whole body Na(+) and ultimately died. When taken together, results from these two experiments suggest that enhanced tolerance will only develop in fathead minnows that have experienced a pronounced, relatively long-term cycle of branchial damage and repair.

The role of clinical examination in excluding vascular injury in haemodynamically stable patients with gunshot wounds to the neck. A prospective study of 59 patients.

OBJECTIVE: To prospectively evaluate the safety and accuracy of physical examination in determining the management of stable patients with gunshot wounds to the neck. DESIGN: Prospective study of 59 patients with gunshot wounds to the neck. PATIENTS AND METHODS: Fifty-nine stable patients with gunshot wounds to the neck managed between December 2001 and August 2003. All patients had a physical examination and routine angiography according to a written protocol approved by the research ethics committee. The sensitivity, specificity, and predictive values of physical examination were assessed and compared with the angiographic findings. RESULTS: Thirteen patients with positive findings on physical examination (history of bleeding, haematoma, minimal bleeding, thrill, bruit and pulse deficit) and 10 patients without clinical signs of vascular injury had vascular injury. A sensitivity of 57%, specificity 53%, positive predictive value 43% and negative predictive value of 67% were calculated for physical examination alone in detecting vascular injury. CONCLUSION: Findings on physical examination are not good predictors of vascular injury in stable patients with gunshot wounds to the neck. Our findings question the validity of physical examination alone, as a safe and accurate assessment of patients with gunshot wounds to the neck. Arteriography or ultrasonography is needed to identify vascular injuries.