First record of co - infection of three Clinostomatid parasites in Cichlids [Osteichthyes: Cichlidae] in a tropical freshwater lake

The present study investigated the effects of first record of co-infection of three Clinostomum sp.; Clinostomum Complanatum [Rudolphi, 1819], C. tilapiae [Ukoli, 1966], and Euclinostomum hetereostomum [1809] in Tilapia zilii. There was differential parasitic effects resulting in selection for relatively better adaptiveness to host's microhabitats, more population size, and frequent host location of these parasites during the one year survey [Nov 2007- Oct 2008] in Opi Lake, Nigeria. Prevalence of 9.4% was recorded in C. complanatum, 10.4% in E. heterostomum and 4.8% in C. tilapiae. The parasites were recovered from three major microhabitats of buccal cavity, skin and eye

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.

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

Studies on some fish-borne trematodes in Egypt

Prohemistomum vivax, Haplorchis pumilio, Procerovum calderoni, and Echinochasmus perfoliatus digenetic trematodes of fish eating mammals and man were recovered from experimentally infected dogs with muscles of the following fresh water fishes, Tilapia spp., Glorias lazera, Bagrus bayad, and Shilbe mystus. P.vivax isolated from dogs infested with the muscles of any of these fishes, while H.pumilio and E. perfoliatus recovered from dogs infested with muscles of Tilapia spp. or Bagrus bayad fishes, but P.calderoni recovered from dogs infested with muscles of Tilapia spp., Bagrus bayad, or Shilbe mystus muscles. In this study Tilapia sp. and Shilbe mystus fishes are consider as a new second intermediate host for P.calderoni, while Bagrus bayad is a new second intermediate host for E. perfoliatus

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