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Histological sections of cyst-nematodes in Gymnotus inaequilabiatus. (a) Cysts structures widespread in liver parenchyma. The cysts present ample variety of sizes, formats and thickness of pericystic layer with remarkable inner larvae deposition. There is no evidence of pronounced inflammatory process into parenchyma or next to cysts; (H&E, scale bar = 200 µm); (b) Eosinophilic granule cells deposition surrounding a cyst-wall. There is a formation of connective tissue framework and collagen fibers bellow the cell layer; (H&E, scale bar = 20 µm); (c) Cysts exhibiting extensive internal amorphous material. Melonomacrophages centers are deposited around of the collagen layer; (H&E, scale bar = 50 µm); (d) Two cysts covered by a thick collagen layer. Cystic-wall (dark blue lamina) delimits the larvae structures. Extensive necrotic debris (red) are usually found inside; (TM, scale bar = 50 µm).
Source publication
The aim of this study was to determine the morphometric measures and morphological aspects of nematode-cysts in Gymnotus inaequilabiatus, and the presence of melanomacrophage centers (MMCs) associated with the periphery of cysts and in the liver parenchyma. Adult specimens, 34 female (123.1 ± 43.9g) and 45 male (135.5 ± 43.4g), from Paraguay River,...
Contexts in source publication
Context 1
... nematode-cysts were aligned in a collagenous external capsule with variable levels of thickness (Figure 2a). In some sections, it was possible to identify protein deposits associated with the basophilic amorphous material, suggesting necrosis (Figure 2c, d). ...
Context 2
... nematode-cysts were aligned in a collagenous external capsule with variable levels of thickness (Figure 2a). In some sections, it was possible to identify protein deposits associated with the basophilic amorphous material, suggesting necrosis (Figure 2c, d). Although the structures that surround the cysts configure a granulomatous reaction, degenerative cells and extensive inflammatory reactions, including multinucleated giant cells were not identified. ...
Context 3
... sinusoidal spacing with erythrocytes was observed in some sections without relation with the cyst structures. Besides MMCs periphery, some eosinophilic granule cells were found surrounding the cysts, but these were not quantified (Figure 2b). Pearson´s correlation coefficients are described in Table 2 and 3 to macroscopic and microscopic data, respectively. ...
Context 4
... the inner cyst-wall, the layer was dense and darkly Table 2. Pearson´s Correlation coefficients between biometric body variables (total length, total weight and relative condition factor Kn), liver variables (liver weight and hepatosomatic index) and liver nematode-cysts count in Gymnotus inaequilabiatus (n=79) from the Brazilian Pantanal. colored, covered by an external fibrous layer (Figure 2d). These aspects demonstrate the effectiveness of the encapsulation and isolation process by nematode larvae. ...
Citations
... Gymnotus inaequilabiatus did not tend to affect the liver function, as degenerated hepatocytes and/or extensive granulomatous reactions were not observed and condition factor was not associated with the number of nematode stages in the liver (Galindo et al., 2017). ...
Infection levels with the parasitic nematode Contracaecum osculatum in Eastern
Baltic cod have increased in the last decades. Eastern Baltic cod is transport host for
this parasite that has a high affinity for the liver of the fish. The liver is a highly vital
organ and damage to the liver tissue can result in reduced functionality of the organ.
Previous studies have revealed that cod with high infections loads reveal impaired
physiological performance, reduced nutritional condition and show signs of having
a liver disease. Yet, little is known about the pathological changes and inflammatory
reactions of the cod liver related to the infections. In this study, we performed his�tological examinations on 30 Baltic cod livers caught in the eastern part of the Baltic
Sea (length; 38 ± 0.9 cm, weight; 454 ± 34.8 gram) and three Sound cod livers (length;
63 ± 2.9 cm, weight; 3396 ± 300.2 gram) to categorize the degree of inflammation and
its relation to pathological changes in infected cod livers. We further investigated how
C. osculatum infection levels varied with intensity of inflammation and co-infections.
We found that high infection loads with C. osculatum caused severe inflammation
in the liver tissue of cod and reduced fat content of the hepatocytes. Conspicuous
amounts of glycogen were found in the muscle and intestinal epithelial cells of the
nematodes and parasitic co-infections occurred more frequently in the most heavily
infected livers
... Increased occurrence of MAs was observed in the liver of cod Gadus morhua with hepatic trematodiasis (Borucinska & Morka 2016) and in the heart of leopard coralgrouper Plectropomus leopardus infected with the trematode Pearsonellum corventum (Overstreet & Thulin 1989). A variety of other parasites can elicit inflammatory re sponses, such as increased MAs, in fish; these parasites include coccidia (Vogelbein et al. 1987), myxo-zoa (Dyková 1984), monogeneans (De Vico et al. 2008), and nematodes (Galindo et al. 2017). ...
The response of macrophage aggregates in fish to a variety of environmental stressors has been useful as a biomarker of exposure to habitat degradation. Total volume of macrophage aggregates (MAV) was estimated in the liver and spleen of white perch Morone americana from Chesapeake Bay using stereological approaches. Hepatic and splenic MAV were compared between fish populations from the rural Choptank River (n = 122) and the highly urbanized Severn River (n = 131). Hepatic and splenic MAV increased with fish age, were greater in females from the Severn River only, and were significantly greater in fish from the more polluted Severn River (higher concentrations of polycyclic aromatic hydrocarbons, organochlorine pesticides, and brominated diphenyl ethers). Water temperature and dissolved oxygen had a significant effect on organ volumes, but not on MAV. Age and river were most influential on hepatic and splenic MAV, suggesting that increased MAV in Severn River fish resulted from chronic exposures to higher concentrations of environmental contaminants and other stressors. Hemosiderin was abundant in 97% of spleens and was inversely related to fish condition and positively related to fish age and trematode infections. Minor amounts of hemosiderin were detected in 30% of livers and positively related to concentrations of benzo[a] pyrene metabolite equivalents in the bile. This study demonstrated that hepatic and splenic MAV were useful indicators in fish from the 2 tributaries with different land use characteristics and concentrations of environmental contaminants. More data are needed from additional tributaries with a wider gradient of environmental impacts to validate our results in this species.
... The Gymnotidae family has been studied from the genetic, taxonomic, endoparasitic fauna and ecological standpoints (Willink et al., 2000;Albert et al., 2005;Scacchetti et al., 2011;Galindo et al., 2017). Although these studies are numerous, there are no reports about anatomy, histology, and histopathological features of the kidney and were not even reported biometrics and histometric traits in this species. ...
... These conditions are characterized by low oxygen level, which probably induces anatomical and functional adaptations, such as breathing air through accessory airbreathing organs or via gill system (Crampton, 1998;Moraes et al., 2002). Furthermore, fish are subjected to adverse situations such as large temperature fluctuations, food scarcity, and a broad spectrum of pathological agents (Bonga, 1997;Galindo et al., 2017). ...
... The coefficient measured between gross lesions and RSI suggests that adult or aged specimens with higher indices would tend to sustain more injuries through the organ. The negative correlations with MMCs may be due to these structures remaining aggregated around the granulomatous lesions and moderately dispersed in the renal parenchyma, a feature previously reported to hepatic nematode-cysts granulomas (Galindo et al., 2017). In the present study, MMCs account for a substantial fraction of the volumetric density in both the head and exocrine kidney mostly composed of melanin (Agius, Roberts, 2003;Kumar et al., 2016). ...
The Gymnotus inaequilabiatus is a Neotropical fish widely distributed in marginal areas of bays. The aim of this study was to describe the main histological and histopathological traits in the head and exocrine kidney. Here, histometric and structural density techniques were associated with renosomatic index (RSI). The kidney was processed for light microscopy. Lipofuscin and hemosiderin content were visually estimated in the melonomacrophages centers (MMCs). All the biometric body variables were correlated with RSI, especially the kidney weight and gross lesions count. The general architecture of head and exocrine kidney was similar to that described for other teleost species. MMCs were prevalent in both portions and correlated with RSI in the head and exocrine kidney. Granulomatous structures were often observed in both portions; however, they were associated only in the exocrine kidney with RSI. Of all the structures hystometrically estimated, only proximal tubular diameter and thickness, and distal tubular thickness were correlated to renosomatic index. The RSI is an useful biometric variable that represent some physiological and morphological characteristics of kidney in G. inaequilabiatus. These findings may be used in future studies to evaluate the effects of environmental stressors on the renal adaptative physiological process.
... A lot of parasites, such as helminths or copepods, go through different life stages (i.e. cyst, egg and larval stages) [14][15][16][17] that are often difficult or nearly impossible to locate [18] and even if some of them can be detected, morphological differences are insufficient to differentiate between species from these development stages [19][20]. In addition, these surveys usually focus on a single class of parasites, ecto-or endoparasites [21][22][23][24] and sometimes even on specific genera [25][26][27]. ...
Next-generation sequencing methods are increasingly used to identify eukaryotic, unicellular and multicellular symbiont communities within hosts. In this study, we analyzed the non-specific reads obtained during a metabarcoding survey of the bacterial communities associated to three different tissues collected from 13 wild Mediterranean teleost fish species. In total, 30 eukaryotic genera were identified as putative parasites of teleosts, associated to skin mucus, gills mucus and intestine: 2 ascomycetes, 4 arthropods, 2 cnidarians, 7 nematodes, 10 platyhelminthes, 4 apicomplexans, 1 ciliate as well as one order in dinoflagellates (Syndiniales). These results highlighted that (1) the metabarcoding approach was able to uncover a large spectrum of symbiotic organisms associated to the fish species studied, (2) symbionts not yet identified in several teleost species were putatively present, (3) the parasitic diversity differed markedly across host species and (4) in most cases, the distribution of known parasitic genera within tissues is in accordance with the literature. The current work illustrates the large insights that can be gained by making maximum use of data from a metabarcoding approach.
... Other study indicated that liver infected with T. canis that the larval stage was coated with fibrous connective tissue, macrophages, neutrophils, and eosinophilic granule cells since vascular alterations such as perivascular inflammatory reaction, obstructive thrombosis and coagulative necrosis, were observed. since coagulative necrosis was most commonly occur due to loss of blood supply lead to lack of oxygen (hypoxia) causes cell death in a localized area (20) and that deal with study that indicated accumulation of mononuclear cells in the hepatic parenchyma and fibrous connective tissue proliferation in portal areas around the biliary tubules of T. canis infected rats (19). ...
Toxocariasis is a zoonotic parasitic disease caused by Toxocara canis nematode emberyonated egg which is usually transmitted to humans mainly in children via the faecal-oral route, or accidently ingested larvae from uncooked liver or meat of infected ruminants and poultry. T. canis larvae remains a problem throughout the world because it remains on arrested stage without development to adult stage and causes multisystem disease in the paratenic hosts such as humans, ruminants, poultry and rodents, most infections are asymptomatic and manifests in humans causing the well-characterized syndrome; Visceral Larva Migrans (VLM). The result of this study indicated detection of T. canis larval stage in liver tissues of infected rabbits at third week post infection. In conclusion the result indicated the possibility of using histopathological examination to diagnosis if there was an infection with T. canis larval stage in paratenic host tissues. It was also recommend that this test could be used to ensure that meat and its products of any local or imported are free from this infection.
... On the other hand, larvae of Brevimulticaecum sp. in fish are scarce. To date, Brevimulticaecum larvae have been reported in the celomatic cavity, hepatic parenchyma, mesentery, skeletal muscle and stomach wall of Gymnotus inaequilabiatus (VIEIRA et al., 2010) and GALINDO et al. (2017) suggest that G. inaequilabiatus acts as a paratenic host to nematodes in the larval stage. ...
This study evaluated the endohelminthic parasites of native baitfish Gymnotus spp. collected from different baitfish farming in the Pantanal basin, State of Mato Grosso do Sul, Central Brazil. From 99 fish collected for parasitological analysis, all of them were found to be parasitized by at least 1 parasite per host. A total of 4504 parasites were collected comprising the following taxa: Digenea, Nematoda, Pentastomida and Acanthocephala. Rondonia rondoni and Goezia sp. as well as Alofia sp. Were registered for the first time in farmed Gymnotus spp. The parasite species diversity in the host is discussed in this study. ENDOPARASITOS DE Gymnotus sp. (GYMNOTIFORMES: GYMNOTIDAE) DE ISQUEIROS COMERCIAIS NA BACIA DO PANTANAL, BRASIL CENTRAL RESUMO Este estudo avaliou os parasitos endohelmintos do peixe nativo Gymnotus spp. coletado de diferentes isqueiros comerciais na bacia do Pantanal, Mato Grosso do Sul, Brasil Central. De 99 peixes coletados para análise parasitológica, todos estavam parasitados por pelo menos um parasito por hospedeiro. Um total de 4504 parasitos foram coletados compreendendo os seguintes táxons: Digenea, Nematoda, Pentastomida e Acanthocephala. Rondonia rondoni e Goezia sp. bem como Alofia sp. foram registrados pela primeira vez em Gymnotus spp. A diversidade de espécies de parasitos no hospedeiro é discutida neste estudo.
