Parasites (Monogenea) of tilapias Oreochromis niloticus and Coptodon rendalli (Cichlidae) in a river spring in Brazil.

In the present study, we examined 30 individuals of introduced African cichlids, Oreochromis niloticus and Coptodon rendalli, collected in a river spring of the Pardo River, Paranapanema River basin, southeastern Brazil. Based on morphological and molecular analyses of the partial LSU rDNA gene, we identified four species of monogeneans, Cichlidogyrus tilapiae, C. thurstonae, C. mbirizei, and Scutogyrus longicornis on the gills of O. niloticus, whereas individuals of C. rendalli were infested only with C. papernastrema. This is the first record of C. mbirizei and C. papernastrema in tilapias from Brazil. The ecological consequences of the introduction of exotic species of tilapia such as O. niloticus and C. rendalli along with their monogenean parasites in a wild environment represented by a river spring are discussed. Our new molecular data on Cichlidogyrus and Scutogyrus contribute to the investigation of the phylogenetic interrelationships of these widely distributed genera of monogeneans since their species composition is still unsettled.

Title: Parasites (Monogenea) des tilapias Oreochromis niloticus et Coptodon rendalli (Cichlidae) dans une source au Brésil. Abstract: Dans la présente étude, nous avons examiné 30 individus de cichlidés africains introduits, Oreochromis niloticus et Coptodon rendalli, collectés dans une source fluviale du fleuve Pardo, bassin du fleuve Paranapanema, dans le sud-est du Brésil. Sur la base d'analyses morphologiques et moléculaires du gène partiel de l'ADNr LSU, nous avons identifié quatre espèces de monogènes, Cichlidogyrus tilapiae, C. thurstonae, C. mbirizei et Scutogyrus longicornis sur les branchies d'O. niloticus, alors que les individus de C. rendalli étaient infestés uniquement par C. papernastrema. Il s'agit du premier signalement de C. mbirizei et C. papernastrema chez des tilapias du Brésil. Les conséquences écologiques de l'introduction d'espèces exotiques de tilapia telles que O. niloticus et C. rendalli ainsi que leurs monogènes parasites dans un environnement sauvage représenté par une source fluviale sont discutées. Nos nouvelles données moléculaires sur Cichlidogyrus et Scutogyrus contribuent à l'étude des interrelations phylogénétiques de ces genres de monogènes largement distribués puisque leur composition spécifique est encore incertaine.

Therapeutic bath of mint hydrolate in the control of monogenea for four tilapia species / Banho terapêutico de hidrolato de hortelã no controle de parasitas para quatro espécies de tilápia

This work aimed to evaluate a therapeutic bath of mint (Mentha x villosa) hydrolate in the control of monogeneans for four tilapia species (Oreochromis niloticus, Oreochromis aureus, Oreochromis mossambicus, and Oreochromis hornorum) reared in the same environment (pond). After two months, 60 individuals of O. niloticus were divided into six groups of ten fish each. Three of them were submitted to a 1-hour therapeutic bath of mint hydrolate at the concentration of 20 mL·L-1, and the others were used as a control group. This process was repeated for O. aureus, O. mossambicus and O. hornorum. After that, mucus and gills were analyzed to determine parasitological indices (prevalence, mean abundance, and mean intensity) for monogeneans. The efficacy of mint hydrolate bath was set as 73.5, 79, 80.7, and 84.5% for O. hornorum, O. aureus, O. mossambicus and O. niloticus, respectively, against the monogeneans in the mucus. All species in this work demonstrated similar parasitic susceptibility when reared in the same environment. In addition, the use of mint therapeutic bath demonstrated efficacy in the control of monogeneans in mucus for all evaluated species.(AU)

Este trabalho teve como objetivo avaliar um banho terapêutico de hidrolato de hortelã (Mentha x villosa) no controle de monogenéticos para quatro espécies de tilápia (Oreochromis niloticus, Oreochromis aureus, Oreochromis mossambicus e Oreochromis hornorum) criadas no mesmo ambiente (viveiro). Após dois meses, 60 indivíduos de O. niloticus foram divididos em seis grupos de dez peixes cada um. Três deles foram submetidos a um banho terapêutico de uma hora de hidrolato de hortelã na concentração de 20 mL·L-1, e os demais foram utilizados como grupo controle. Esse processo foi repetido para O. aureus, O. mossambicus e O. hornorum. Em seguida, o muco e as brânquias foram analisados para determinar os índices parasitológicos (prevalência, abundância média e intensidade média). A eficácia do banho de hidrolato de hortelã no muco foi medida em 73,5, 79, 80,7 e 84,5% para O. hornorum, O. aureus, O. mossambicus e O. niloticus, respectivamente. Todas as espécies de tilápia avaliadas neste trabalho demonstraram suscetibilidade parasitária semelhante quando criadas no mesmo ambiente, no entanto o uso do banho terapêutico de hortelã demonstrou eficácia no controle de monogenéticos no muco para todas as espécies avaliadas.(AU)

Morpho-molecular characterization of Gyrodactylus parasites of farmed tilapia and their spillover to native fishes in Mexico.

Translocation of fishes for aquaculture has resulted in the co-introduction of some of their parasites. African cichlid fishes, generically called "tilapias" have been introduced worldwide, along with their monogenean parasites. In a nation-wide survey, we characterised monogeneans of the genus Gyrodactylus infecting farmed "tilapia" throughout Mexico. We also collected native fishes around farms, to look for potential parasite spillover from cultured fishes. Monogeneans were identified taxonomically using morphological and molecular characters. Originally African, pathogenic Gyrodactylus cichlidarum was recorded in every farm surveyed, infecting different "tilapia" varieties, as well as three native cichlid fish species. Previously, we had shown that G. cichlidarum also infects native, non-cichlid fishes in Mexico. We also recorded that Gyrodactylus yacatli is widely distributed in Mexico, infecting cultured "tilapia" and native fishes; and present data indicating that this is a further translocated African parasite. A third, unidentified gyrodactylid infected farmed and native fishes in Chiapas, southern Mexico; we describe the new species as Gyrodactylus shinni n. sp., and provide evidence that this is a third monogenean translocated with African fish. The wide distribution of exotic parasites co-introduced with "tilapia" and their spillover to native fishes may have an important impact on the ichthyofauna in Mexico, one the world's megadiverse countries.

Molecular Effects of Silver Nanoparticles on Monogenean Parasites: Lessons from Caenorhabditis elegans.

The mechanisms of action of silver nanoparticles (AgNPs) in monogenean parasites of the genus Cichlidogyrus were investigated through a microarray hybridization approach using genomic information from the nematode Caenorhabditis elegans. The effects of two concentrations of AgNPs were explored, low (6 µg/L Ag) and high (36 µg/L Ag). Microarray analysis revealed that both concentrations of AgNPs activated similar biological processes, although by different mechanisms. Expression profiles included genes involved in detoxification, neurotoxicity, modulation of cell signaling, reproduction, embryonic development, and tegument organization as the main biological processes dysregulated by AgNPs. Two important processes (DNA damage and cell death) were mostly activated in parasites exposed to the lower concentration of AgNPs. To our knowledge, this is the first study providing information on the sub-cellular and molecular effects of exposure to AgNPs in metazoan parasites of fish.

Redescription of Austrodiplostomum compactum (Trematoda: Diplostomidae) from its Type Host and Locality in Venezuela, and of Austrodiplostomum mordax from Argentina.

Austrodiplostomum compactum from Nannopterum brasilianus, and its metacercaria from Geophagus sp. and Oreochromis mossambicus captured (1979) at its type locality, Valencia Lake, Venezuela, by the author, are redescribed. The adult is characterized by its large body size, and an oral sucker smaller than the pharynx. The metacercaria has a similar body size as the adult, and the small genital primordia occupy 4.1-7.3% of body length. Experimental infections in chickens with metacercariae of Diplostomulum mordax from brains of Odonthestes bonariensis, captured (2015) at Dique Paso de las Piedras, near Bahia Blanca City, Buenos Aires Province, Argentina, resulted in 10 adults 5 days postexposure. These adults correspond to Austrodiplostomum mordax as described from N. brasilianus at Lacombe Lagoon, Buenos Aires Province, and differ from A. compactum in their smaller body size, and an oral sucker larger than the pharynx. The metacercaria has a similar body size as the adult and differs mainly in that the larger genital primordia occupy 11.6-13.8% of body length. The status of earlier published Austrodiplostomum species in the American continent is discussed in view of available morphological and molecular data. A lectotype of A. mordax is here designated, and Austrodiplostomum ostrowskiae is considered as a new synonym of A. compactum.

Effect of propolis extract on the parasite load of Nile tilapias reared in cages / Influência do extrato de própolis na carga parasitária de tilápias do Nilo criadas em tanques-rede

Due to increase in demand for healthy and chemical residue-free products, natural therapeutic substances are being enhanced in fish cultivation. Current study evaluates in an unprecedented way (Tesearchoxygen), the species is he effect of propolis on the parasite charge of the Nile tilapia (Oreochromis niloticus) reared in fish cages. Six hundred male Nile tilapia (200g) conditioned in ten 1 m3 cages were used. Two treatments with five replications each were provided: TCON: control (extruded meal without propolis) and TPRO: extruded meal with 4% propolis extract. Parasite collection occurred on 0, 35, 70 and 105 days. At the same time, fillet was weighed and fish standard length measured. Temperature was kept within the comfort range for the species during the experimental period (> 25ºC). Trichodinids and Monogenoids (Dactylogyridae) were detected in the two treatments. There was no statistical difference (p > 0.05) in mean parasite intensity (total parasites/specimens with parasites) and abundance (total parasites/examined specimens) among treatments in the four evaluation periods. Lowest parasite prevalence occurred after 70 days in TPRO (26.66%). There was no statistical difference (p > 0.05) among treatments with regard to fillet weight and standard length of fish. Results show that propolis extract 4% did not significantly affect parasite load, fillet weight and standard length of Nile tilapia.

Devido ao aumento da demanda por produtos saudáveis e livres de resíduos químicos, a utilização de terapêuticos naturais na criação de peixes tem sido cada vez mais estimulada. O objetivo do presente trabalho foi avaliar de forma inédita o efeito do extrato de própolis sobre a carga parasitária de tilápiasdo-Nilo (Oreochromis niloticus) criadas em tanque-rede. Foram utilizados 600 machos revertidos de tilápia-do-Nilo (200g) acondicionados em 10 tanques-rede de 1 m3 . Foram utilizados dois tratamentos com cinco repetições: TCON: controle (ração extrusada sem própolis) e TPRO: ração extrusada contendo extrato de própolis a 4%. As coletas de parasitas foram realizadas nos dias 0, 35, 70 e 105 dias. Paralelamente, foi realizado a mensuração do peso do filé e comprimento padrão. A temperatura durante o período experimental se manteve dentro da faixa de conforto para a espécie. Foi verificada a presença de tricodinídeos e Monogenoides (Dactylogyridae) em ambos os tratamentos. Não houve diferença estatística (p > 0,05) nos valores de intensidade (total de parasitas/número de indivíduos parasitados) e abundância (total de parasitas/total de indivíduos examinados) média parasitária entre os tratamentos nos quatro períodos de avaliação. A menor prevalência parasitária foi aos 70 dias em TPRO (26,66%). Não foi constatada diferença estatística (p > 0,05) entre os tratamentos na mensuração do peso do filé e comprimento padrão. Conclui-se que o extrato de própolis a 4% não influenciou significativamente a carga parasitária, no peso do filé e no comprimento padrão em tilápias-do-Nilo.

Effect of propolis extract on the parasite load of Nile tilapias reared in cages / Influência do extrato de própolis na carga parasitária de tilápias do Nilo criadas em tanques-rede

Due to increase in demand for healthy and chemical residue-free products, natural therapeutic substances are being enhanced in fish cultivation. Current study evaluates in an unprecedented way (Tesearchoxygen), the species is he effect of propolis on the parasite charge of the Nile tilapia (Oreochromis niloticus) reared in fish cages. Six hundred male Nile tilapia (200g) conditioned in ten 1 m3 cages were used. Two treatments with five replications each were provided: TCON: control (extruded meal without propolis) and TPRO: extruded meal with 4% propolis extract. Parasite collection occurred on 0, 35, 70 and 105 days. At the same time, fillet was weighed and fish standard length measured. Temperature was kept within the comfort range for the species during the experimental period (> 25ºC). Trichodinids and Monogenoids (Dactylogyridae) were detected in the two treatments. There was no statistical difference (p > 0.05) in mean parasite intensity (total parasites/specimens with parasites) and abundance (total parasites/examined specimens) among treatments in the four evaluation periods. Lowest parasite prevalence occurred after 70 days in TPRO (26.66%). There was no statistical difference (p > 0.05) among treatments with regard to fillet weight and standard length of fish. Results show that propolis extract 4% did not significantly affect parasite load, fillet weight and standard length of Nile tilapia.(AU)

Devido ao aumento da demanda por produtos saudáveis e livres de resíduos químicos, a utilização de terapêuticos naturais na criação de peixes tem sido cada vez mais estimulada. O objetivo do presente trabalho foi avaliar de forma inédita o efeito do extrato de própolis sobre a carga parasitária de tilápiasdo-Nilo (Oreochromis niloticus) criadas em tanque-rede. Foram utilizados 600 machos revertidos de tilápia-do-Nilo (200g) acondicionados em 10 tanques-rede de 1 m3 . Foram utilizados dois tratamentos com cinco repetições: TCON: controle (ração extrusada sem própolis) e TPRO: ração extrusada contendo extrato de própolis a 4%. As coletas de parasitas foram realizadas nos dias 0, 35, 70 e 105 dias. Paralelamente, foi realizado a mensuração do peso do filé e comprimento padrão. A temperatura durante o período experimental se manteve dentro da faixa de conforto para a espécie. Foi verificada a presença de tricodinídeos e Monogenoides (Dactylogyridae) em ambos os tratamentos. Não houve diferença estatística (p > 0,05) nos valores de intensidade (total de parasitas/número de indivíduos parasitados) e abundância (total de parasitas/total de indivíduos examinados) média parasitária entre os tratamentos nos quatro períodos de avaliação. A menor prevalência parasitária foi aos 70 dias em TPRO (26,66%). Não foi constatada diferença estatística (p > 0,05) entre os tratamentos na mensuração do peso do filé e comprimento padrão. Conclui-se que o extrato de própolis a 4% não influenciou significativamente a carga parasitária, no peso do filé e no comprimento padrão em tilápias-do-Nilo.(AU)

Triple trouble? Invasive poeciliid fishes carry the introduced tilapia pathogen Gyrodactylus cichlidarum in the Mexican highlands.

As part of ongoing surveys of the gyrodactylid parasite fauna of freshwater fishes in Mexico, we recorded the infection of three species of poeciliids (Poecilia mexicana, Poeciliopsis gracilis, and Pseudoxiphophorus bimaculatus [syn.=Heterandria bimaculata]) with Gyrodactylus cichlidarum, a monogenean parasite of cichlid fishes, which has been co-introduced globally with its translocated, African "tilapia" hosts. This tilapia pathogen was found on poeciliid fishes both within their native distribution range in the Gulf of Mexico slope, as well as on invasive species artificially introduced to the Mexican highlands, to rivers draining into the Pacific Ocean. Identity of G. cichlidarum was confirmed by morphological and molecular analyses. Prevalence and abundance of infection were low, but this is the first record of G. cichlidarum infecting poeciliids (Cyprinodontiformes), which are distantly related to this parasite's primary cichlid fish hosts (Perciformes). This study provides evidence that G. cichlidarum, a recognized pathogen which has been co-introduced globally with its cichlid fish hosts for aquacultural purposes, is able to infect non-related poeciliid fishes inhabiting water bodies adjacent to tilapia farms, thereby potentially increasing its ability to disperse between farms and different river basins. It is of particular concern that G. cichlidarum was found on poeciliids, as these invasive fishes have been introduced worldwide and could act as carriers for this parasite known to induce significant mortality of farmed tilapias - globally, the second most important freshwater aquaculture fish group, after the carps.

First record of Chilodonella hexasticha (Ciliophora: Chilodonellidae) in Brazilian cultured fish: a morphological and pathological assessment.

Chilodonelids are small ciliated protozoans found worldwide and can be dangerous in culture conditions. This study presents morphometric data on the ciliate Chilodonella that is found in cultured Nile tilapia (Oreochromis niloticus), native bait fish tuvira (Gymnotus aff. inaequilabiatus) and native pacu (Piaractus mesopotamicus) and includes a histopathological assessment of the changes that occur in the pacu. For parasitic diagnosis, skin and gill samples were scraped onto slides, dried at room temperature, stained with Giemsa or impregnated with silver nitrate, and the measurements were obtained from photomicrographs. In the diseased pacu, the first gill arch was collected and fixed in a 10% buffered formalin solution for histopathological analysis. Parasite specimens from the different collection sites were identified morphologically as C. hexasticha Kiernik (1909). Diseased fish exhibited depigmentation, skin ulceration, scale loss, excessive mucus production and gill lesions. Histopathological analysis of pacu gills displayed epithelial proliferation with mononuclear inflammatory infiltrate, hemorrhages, and scattering necrosis. In Brazilian-farmed fish this is the first record of C. hexasticha, which has great pathogenic potential in cultured freshwater species. In addition, two new hosts are presented.

Centrocestus formosanus (Opisthorchiida: Heterophyidae) como causa de muerte de alevines de tilapia gris Oreochromis niloticus (Perciforme: Cichlidae) en el Pacífico seco de Costa Rica

Centrocestus formosanus (Opisthorchiida: Heterophyidae) as a cause of death in gray tilapia fry Oreochromis niloticus (Perciforme: Cichlidae) in the dry Pacific of Costa Rica. Centrocestus formosanus is a zoonotic trematode from Asia and has been mainly associated as cause of death of cultured fish. To identify pathogen trematode species in tilapia fry (Oreochromis niloticus) and to determine mollusks hosting these parasites, freshwater mollusks were collected from tilapia cultured ponds and experimental infections were carried out with tilapia fries and different mollusk species. A total of 907 freshwater mollusks were obtained from tilapia ponds and were identified to species level, four gastropods and one bivalve were determined: Melania tuberculata, Melanoides turricula, Pomacea flagellata, Haitia cubensis and Anodontiles luteola. For the first time, the presence of M. turricula and H. cubensis are reported in Costa Rica. Seven morphotypes of cercariae (Xifiodiocercaria, Equinostoma, Oftalmocercaria, Parapleurolofocercus, Cistocerca, Furcocercaria and Leptocercaria) parasitizing all five species of mollusks were found, all of distome type. Experimental exposure of tilapia fry to M. tuberculata demonstrated that the parapleurolofocercus morphotype found in the mollusk is in accordance with the finding of C. formosanus in tilapia fry. An abundance and mean intensity of 1018-1027 digeneans per gill in each exposed fish was determined. Centrocestus formosanus is reported for the first time in Costa Rica, for which the primary and secondary intermediate hosts were also determined. Rev. Biol. Trop. 58 (4): 1453-1465. Epub 2010 December 01.

Centrocestus formosanus es un parásito trematodo zoonótico originario de Asia asociado con muertes de peces principalmente de cultivo. 907 moluscos provenientes de estanques sembrados con tilapias, seleccionados uno por provincia fueron identificados al nivel taxonómico especifico. Se identificaron cuatro gastrópodos y un bivalvo: M. tuberculata, M. turricula, P. flagellata, H. cubensis y A. luteola. Se reporta, por primera vez, la presencia de dos especies de moluscos en Costa Rica. Se identificaron siete morfotipos de cercarias parasitando las cinco especies de moluscos encontradas. En la segunda exposición experimental se demostró que el morfotipo parapleurolofocercus encontrado en M. tuberculata concuerda con el hallazgo de C. formosanus en alevines de tilapia, después del examen clínico, anatomopatológico y parasitológico realizado a los alevines expuestos. Las metacercarias fueron extraídas del quiste utilizando microagujas y micropinzas lavadas en solución salina fisiológica (0.65%), fijadas en formol caliente al 4% y después esquematizadas con una cámara clara adaptada a un microscopio fotónico, estimándose una abundancia e intensidad media de 1018-1027 digeneos por branquia en cada pez parasitado, determinándose así el hospedador intermediario primario y secundario del parásito. En el presente trabajo se reporta por primera vez Centrocestus formosanus en Costa Rica.

[Centrocestus formosanus (Opisthorchiida: Heterophyidae) as a cause of death in gray tilapia fry Oreochromis niloticus (Perciforme: Cichlidae) in the dry Pacific of Costa Rica]. / Centrocestusformosanus (Opisthorchiida: Heterophyidae) como causa de muerte de alevines de tilapia gris Oreochromis niloticus (Perciforme: Cichlidae) en el Pacifico seco de Costa Rica.

Centrocestusformosanus is a zoonotic trematode from Asia and has been mainly associated as cause of death of cultured fish. To identify pathogen trematode species in tilapia fry (Oreochromis niloticus) and to determine mollusks hosting these parasites, freshwater mollusks were collected from tilapia cultured ponds and experimental infections were carried out with tilapia fries and different mollusk species. A total of 907 freshwater mollusks were obtained from tilapia ponds and were identified to species level, four gastropods and one bivalve were determined: Melania tuberculata, Melanoides turricula, Pomacea flagellata, Haitia cubensis and Anodontiles luteola. For the first time, the presence of M. turricula and H. cubensis are reported in Costa Rica. Seven morphotypes of cercariae (Xifiodiocercaria, Equinostoma, Oftalmocercaria, Parapleurolofocercus, Cistocerca, Furcocercaria and Leptocercaria) parasitizing all five species of mollusks were found, all of distome type. Experimental exposure of tilapia fry to M. tuberculata demonstrated that the parapleurolofocercus morphotype found in the mollusk is in accordance with the finding of C. formosanus in tilapia fry. An abundance and mean intensity of 1018-1027 digeneans per gill in each exposed fish was determined. Centrocestus formosanus is reported for the first time in Costa Rica, for which the primary and secondary intermediate hosts were also determined.

The histopathology of the infection of Tilapia rendalli and Hypostomus regani (Osteichthyes) by lasidium larvae of Anodontites trapesialis (Mollusca, Bivalvia).

It is described the histopathology of the infection of Tilapia rendalli (Osteichthyes, Perciformes, Cichlidae) and Hypostomus regani (Osteichthyes, Siluriformes, Loricariidae) by lasidium larvae of Anodontites trapesialis (Mollusca, Bivalvia, Mycetopodidae). The larvae were encysted within the epidermis of the host, being surrounded by a thin hyaline membrane, 3-6 microm thick, of parasite origin. A proliferative host cell reaction did not occur. The histopathology of the infection shows that the lesions induced by the parasites are minimal. However, the numerous small lesions produced by the release of the larvae may provide optimal conditions for the infection by opportunistic pathogens, namely fungus, which may eventually cause the death of the host.

The distribution of Biomphalaria spp. in different habitats in relation to physical, biological, water contact and cognitive factors in a rural area in Minas Gerais, Brazil.

A total of 256 sites in 11 habitats were surveyed for Biomphalaria in Melquiades rural area (State of Minas Gerais) in August and November 1999 and in March 2000. Of the 1,780 Biomphalaria collected, 1,721 (96.7%) were B. glabrata and 59 (3.3%) B. straminea. Snails were found in all habitats except in wells, with the largest mean numbers in tanks, seepage ponds and canals, and the smallest numbers in springs, rice fields and fishponds. People's knowledge of the occurrence of Biomphalaria at the collection sites and the presence of Biomphalaria ova were strongly correlated with the occurrence of snails, and distance between houses and collection sites, as well as water velocity were inversely correlated with Biomphalaria occurrence (p < 0.001). The strongest predictor o f Biomphalaria occurrence was the presence of tilapia fish in fishponds. Fourteen Biomphalaria (0.8% of all snails) found at 6 sites were infected with Schistosoma mansoni. Suggestions are made for the utilization of local people's knowledge in snail surveys and further studies are recommended on the possible use of tilapia for biological control of Biomphalaria in fishponds, as well as modeling of S. mansoni transmission and reinfection.

The distribution of Biomphalaria spp. in different habitats in relation to physical, biological, water contact and cognitive factors in a rural area in Minas Gerais, Brazil

A total of 256 sites in 11 habitats were surveyed for Biomphalaria in Melquiades rural area (State of Minas Gerais) in August and November 1999 and in March 2000. Of the 1,780 Biomphalaria collected, 1,721 (96.7 percent) were B. glabrata and 59 (3.3 percent) B. straminea. Snails were found in all habitats except in wells, with the largest mean numbers in tanks, seepage ponds and canals, and the smallest numbers in springs, rice fields and fishponds. People's knowledge of the occurrence of Biomphalaria at the collection sites and the presence of Biomphalaria ova were strongly correlated with the occurrence of snails, and distance between houses and collection sites, as well as water velocity were inversely correlated with Biomphalaria occurrence (p < 0.001). The strongest predictor o f Biomphalaria occurrence was the presence of tilapia fish in fishponds. Fourteen Biomphalaria (0.8 percent of all snails) found at 6 sites were infected with Schistosoma mansoni. Suggestions are made for the utilization of local people's knowledge in snail surveys and further studies are recommended on the possible use of tilapia for biological control of Biomphalaria in fishponds, as well as modeling of S. mansoni transmission and reinfection

Caracterización histopatológica de la respuesta de la tilapia (Oreochromis sp) a una infección mixta por myxosporidios: estudio en un caso natural / Histopathological characterization of tilapia (Orechromis sp) response to a mixed infection by myxosporean parasites: a natural case

Se diagnosticó una infección mixta por protozoarios myxosporidios en un caso natural en cuarenta tilapias (Oreochromis sp). A la observación macroscópica, los peces presentaban pequeños nódulos blanquecinos en las branquias, oscurecimiento de la piel, exoftalmia y pérdida del apetito. La necropsia mostró aumento del volumen abdominal, congestión y engrosamiento del intestino medio y posterior, ocho de los peces presentaron ascitis. Se encontraron panesporoblastos en la mucosa y submucosa intestinal, páncreas, riñón, encéfalo y branquias, aunque los encontrados en estas últimas presentaban forma y tamaño diferentes al de los demás panesporoblastos. La única respuesta del organismo a la infección fue la formación de una cápsula fibrosa alrededor del panesporoblasto. La tinción de Giemsa mostró la estructura bipolar de las cápsulas. Por el tamaño y forma, se sugiere que la causa de la infección fue la formación de una cápsula fibrosa alrededor del panesporoblasto. La tinción de Giemsa mostró la estructura bipolar de las cápsulas. Por el tamaño y forma, se sugiere que la causa de la infección sistémica podría ser Myxosoma sp, y en el caso de la infección branquial, Myxobolus sp o Henneguya sp. Sin embargo, se requiere un estudio antigénico para llegar a un diagnóstico etiológico fidedigno. La importancia del presente trabajo radica en que las pérdidas económicas por esta etiología pueden ser significativas y se han hecho muy pocos informes de estas parasitosis en tilapia

Short report: gnathostomiasis in Mexico.

Gnathostomiasis is an important food-borne parasitic zoonosis that is endemic mainly in Asian countries where some people prefer to eat raw freshwater fish. In North America, the first recorded case of gnathostomiasis was in Mexico in 1970, and the numbers of gnathostomiasis patients in Mexico seems to be increasing dramatically with time. However, the epidemiology of this disease in Mexico has never been described in detail. Here we review the current status of gnathostomiasis in Mexico.

[Evaluation of chemotherapeutic agents against cichlidogyriasis in tilapia (Oreochromis hornorum) in Mexico]. / Evaluación de quimioterapéuticos contra la ciclidogiriasis en tilapia (Oreochromis hornorum) en México.

To evaluate the efficacy of seven compounds against the cichlidogyriasis of tilapia fish (Oreochromis hornorum), two experiments were carried out. In one, 160 naturally infected fish with a mean burden of 33.4 parasites/animal were used. In another, 1600 fish with a burden of 49.9 parasites/fish were used. Fish were randomly divided into eight equal groups and received three treatments as submersion baths: methylene blue, malachite green, potassium permanganate, sodium chloride, formaldehyde, copper sulfate and triclorfon, and a non-treated control. Five days after the last treatment, all fish were killed and dissected to quantify the remaining parasites. All data were submitted to an ANOVA analysis. All groups compared to the control showed statistical difference (P < 0.01), with better efficacy at higher doses. Sodium chloride, potassium permanganate and triclorfon are highly efficient in the control of cichlidogyriasis of tilapia fish, but care should be taken with the toxicity of the two first compounds.