First molecular data for Lernaea cyprinacea (Copepoda: Cyclopoida) infesting Odontesthes bonariensis, a commercially important freshwater fish in Argentina.

Parasitic copepods of the family Lernaeidae are often found infesting freshwater fishes worldwide. They cause lernaeosis, a disease that can lead to serious pathogenic effects on their fish hosts. The most common lernaeid is the Lernaea cyprinacea, which has been widely introduced through importation of tropical fishes, e.g. cyprinids. In South America, it is one of the most common parasites both in wild and in farmed fish in the central region of Argentina. The silverside Odontesthes bonariensis is the most important fish of the sport fisheries of Argentina and one of the fish most affected by lernaeosis. Six specimens of copepods were collected from 30 specimens of O. bonariensis collected in a Pampean shallow lake (33°25'28"S 62°53'56"W) of Córdoba (Argentina). The 28S rRNA gene of L. cyprinacea was amplified by means of PCR to obtain the 28S rDNA sequence. The sequence obtained of this parasite from Argentina showed high genetic similarity with those from various geographical origins. The present study provided molecular characterization of L. cyprinacea in South America for the first time.

First molecular data for Lernaea cyprinacea (Copepoda: Cyclopoida) infesting Odontesthes bonariensis, a commercially important freshwater fish in Argentina / Primeiros dados moleculares para Lernaea cyprinacea (Copepoda: Cyclopoida) infestando Odontesthes bonariensis, um peixe de água doce comercialmente importante na Argentina

Abstract Parasitic copepods of the family Lernaeidae are often found infesting freshwater fishes worldwide. They cause lernaeosis, a disease that can lead to serious pathogenic effects on their fish hosts. The most common lernaeid is the Lernaea cyprinacea, which has been widely introduced through importation of tropical fishes, e.g. cyprinids. In South America, it is one of the most common parasites both in wild and in farmed fish in the central region of Argentina. The silverside Odontesthes bonariensis is the most important fish of the sport fisheries of Argentina and one of the fish most affected by lernaeosis. Six specimens of copepods were collected from 30 specimens of O. bonariensis collected in a Pampean shallow lake (33°25'28"S 62°53'56"W) of Córdoba (Argentina). The 28S rRNA gene of L. cyprinacea was amplified by means of PCR to obtain the 28S rDNA sequence. The sequence obtained of this parasite from Argentina showed high genetic similarity with those from various geographical origins. The present study provided molecular characterization of L. cyprinacea in South America for the first time.

Resumo Os copépodos parasitos da família Lernaeidae são frequentemente encontrados infestando peixes de água doce em todo o mundo, causando a lernaeose, uma doença que pode levar a graves efeitos patogênicos em seus hospedeiros. O lerneídeo mais comum é a Lernaea cyprinacea, que tem sido amplamente introduzida por meio da importação de peixes tropicais, tais como ciprinídeos. Na América do Sul, é um dos parasitos mais comuns em peixes selvagens, bem como em peixes de cultivo na região central argentina. Odontesthes bonariensis é um dos peixes mais importantes para a pesca esportiva na Argentina e um dos mais afetados pela lerneose. Um total de seis espécimes desses copépodes foram coletados de espécimes de 30 O. bonariensis capturados em um lago de pouca profundidade nos Pampas (33°25'28"S 62°53'56"W) em Córdoba (Argentina). O gene 28S rRNA de L. cyprinacea foi amplificado por PCR para obter a sequência do 28S rDNA. A sequência obtida desse parasito da Argentina mostrou alta similaridade genética com aquelas de outras origens geográficas. O presente estudo forneceu, pela primeira vez, uma caracterização molecular de L. cyprinacea na América do Sul.

Parasite community of Pagrus pagrus (Sparidae) from Rio de Janeiro, Brazil: evidence of temporal stability.

One hundred specimens of Pagrus pagrus were necropsied for parasitological study between January and February 2012. These data were compared with data from 90 specimens that had been examined in the year 2000. The fish were collected from Cabo Frio (21-23 ° S, 41-45 ° W), in the state of Rio de Janeiro, Brazil. In the current study a total of 19 parasite species were collected. Sixteen of these were collected in the samples of both 2012 and 2000, thus totaling 25 parasite species in the two studies. All the results were similar to those of the previous study with regard to: dominance of anisakid nematode larvae; correlation between abundance of parasites and host body size; absence of correlations between the size of parasite infrapopulations and host sex; and scarcity of interspecific associations. The only difference between the studies was in the abundance values for Anisakidae, which could be correlated with the seasonal factor of the collection period, which was concentrated in the summer. This is also the period of the South Atlantic Central Water (SACW) phenomenon, during which there is greater host reproductive activity. Therefore, significant stability of the metazoan community structure of P. pagrus was shown.

Parasite community of Pagrus pagrus (Sparidae) from Rio de Janeiro, Brazil: evidence of temporal stability / A comunidade de parasitos metazoários de Pagrus pagrus (Sparidae) do Rio de Janeiro, Brasil: evidências de estabilidade temporal

One hundred specimens of Pagrus pagrus were necropsied for parasitological study between January and February 2012. These data were compared with data from 90 specimens that had been examined in the year 2000. The fish were collected from Cabo Frio (21-23 ° S, 41-45 ° W), in the state of Rio de Janeiro, Brazil. In the current study a total of 19 parasite species were collected. Sixteen of these were collected in the samples of both 2012 and 2000, thus totaling 25 parasite species in the two studies. All the results were similar to those of the previous study with regard to: dominance of anisakid nematode larvae; correlation between abundance of parasites and host body size; absence of correlations between the size of parasite infrapopulations and host sex; and scarcity of interspecific associations. The only difference between the studies was in the abundance values for Anisakidae, which could be correlated with the seasonal factor of the collection period, which was concentrated in the summer. This is also the period of the South Atlantic Central Water (SACW) phenomenon, during which there is greater host reproductive activity. Therefore, significant stability of the metazoan community structure of P. pagrus was shown.

Cem exemplares de Pagrus pagrus foram necropsiados entre janeiro e fevereiro de 2012 para estudos parasitológicos. Esses dados foram comparados com dados de 90 espécimes examinados no ano 2000. Os peixes foram coletados em Cabo Frio (21-23 ° S, 41-45 ° W), no Estado do Rio de Janeiro, Brasil. No presente estudo, foram coletados um total de 19 espécies de parasitos, 16 delas foram coletadas em comum nas amostras de 2012 e 2000, dando um total de 25 espécies de parasitos. Todos os resultados foram semelhantes aos do estudo anterior em: dominância das larvas de anisaquídeos; correlação entre a abundância de parasitos e comprimento total do corpo dos hospedeiros; ausência de correlações entre o tamanho das infrapopulações parasitárias e sexo do hospedeiro e a escassez de associações interespecíficas. A única diferença entre os estudos reside nos valores da abundância de nematóides anisaquídeos, o que poderia ser correlacionado com o fator sazonal do período de coleta que foi concentrada no verão, período que coincide com o fenômeno da Água Central do Atlântico Sul (ACAS), no qual o hospedeiro apresenta maior atividade reprodutiva. Portanto, uma significativa estabilidade da estrutura da comunidade de parasitos de P. pagrus foi evidenciada.