First report of parasitism by Hexametra boddaertii (Nematoda: Ascaridae) in Oxyrhopus guibei (Serpentes: Colubridae).

The current study summarizes the postmortem examination of a specimen of Oxyrhopus guibei (Serpentes, Colubridae) collected in Iguazu National Park (Argentina), and found deceased a week following arrival to the serpentarium of the National Institute of Tropical Medicine (Argentina). Although the snake appeared to be in good health, a necropsy performed following its death identified the presence of a large number of roundworms in the coelomic cavity, with indications of peritonitis and serosal adherence. Additional observations from the necropsy revealed small calcifications in the mesothelium of the coelomic cavity; solid and expressive content in the gallbladder; massive gastrointestinal obstruction due to nematodes; and lung edema and congestion. Histopathological analyses of lung sections also showed proliferative heterophilic and histiocytic pneumonia. Parasites isolated from both the intestine and coelomic cavity were identified as Hexametra boddaertii by a combination of light and scanning electron microscopic examination. Results from this necropsy identify O. guibei as a new host for H. boddaertii, and is the first report of a natural infection by Hexametra in Argentina. Since Hexametra parasites may contribute to several pathological conditions in humans, and with the recent availability of O. guibei specimens through the illegal pet trade, it is necessary to consider the possibility of zoonotic helminth transmission of Hexametra from snake to human.

Checklist of Helminth parasites of Amphibians from South America.

Parasitological studies on helminths of amphibians in South America have increased in the past few years. Here, we present a list with summarized data published on helminths of South American amphibians from 1925 to 2012, including a list of helminth parasites, host species, and geographic records. We found 194 reports of helminths parasitizing 185 amphibian species from eleven countries: Argentina, Brazil, Chile, Colombia, Equador, French Guyana, Guyana, Paraguay, Peru, Uruguay and Venezuela. Helminth biodiversity includes 278 parasite species of the groups Acanthocephala, Nematoda, Cestoda, Monogenea and Trematoda. A list of helminth parasite species per host, and references are also presented. This contribution aims to document the biodiversity of helminth parasites in South American amphibians, as well as identify gaps in our knowledge, which in turn may guide subsequent studies. 

Parasitism by Sphincterodiplostomum musculosum (Digenea, Diplostomidae) metacercariae in the eyes of Steindachnerina insculpta (Characiformes, Curimatidae).

New occurrences and effects of parasitism by metacercariae in fish eyes have recently been discussed in many studies. The aim of the present study was to evaluate the infection levels of the eye flukes Sphincterodiplostomum musculosum Dubois, 1936 (metacercariae) in Steindachnerina insculpta (Fernádez-Yépez, 1948) from three ecosystems under the influence of the Jurumirim reservoir (Paranapanema, Taquari and Veados Rivers). A total of 174 fish specimens were sampled between April 2011 and April 2012. There were high levels of infection by S. musculosum metacercariae in the eyes of S. insculpta from all the sampled ecosystems, thus presenting broad geographical distribution. The histological analyses revealed that the metacercariae were apparently lodged behind the retina. The smaller fish from the Taquari River were less parasitized by metacercariae than the adults. This pattern can be explained by the cumulative effect of parasitism, as demonstrated by the positive correlation between the abundance of metacercariae and fish body size.

Parasitism by Sphincterodiplostomum musculosum (Digenea, Diplostomidae) metacercariae in the eyes of Steindachnerina insculpta (Characiformes, Curimatidae) / Parasitismo por metacercárias de Sphincterodiplostomum musculosum (Digenea, Diplostomidae) nos olhos de Steindachnerina insculpta (Characiformes, Curimatidae)

New occurrences and effects of parasitism by metacercariae in fish eyes have recently been discussed in many studies. The aim of the present study was to evaluate the infection levels of the eye flukes Sphincterodiplostomum musculosum Dubois, 1936 (metacercariae) in Steindachnerina insculpta (Fernádez-Yépez, 1948) from three ecosystems under the influence of the Jurumirim reservoir (Paranapanema, Taquari and Veados Rivers). A total of 174 fish specimens were sampled between April 2011 and April 2012. There were high levels of infection by S. musculosum metacercariae in the eyes of S. insculpta from all the sampled ecosystems, thus presenting broad geographical distribution. The histological analyses revealed that the metacercariae were apparently lodged behind the retina. The smaller fish from the Taquari River were less parasitized by metacercariae than the adults. This pattern can be explained by the cumulative effect of parasitism, as demonstrated by the positive correlation between the abundance of metacercariae and fish body size.

Novas ocorrências e efeitos do parasitismo por metacercárias em olhos de peixe têm sido recentemente discutidas em muitos estudos. O objetivo deste estudo foi avaliar os níveis de infecção dos vermes de olho Sphincterodiplostomum musculosum Dubois, 1936 (metacercárias) em Steindachnerina insculpta (Fernádez-Yépez, 1948) de três ecossistemas influenciados pelo reservatório de Jurumirim (Rios Paranapanema, Taquari e Veados). Um total de 174 espécimes de peixes foi amostrado de Abril/2011 a Abril/2012. Metacercárias de S. musculosum mostraram altos níveis de infecção nos olhos de S. insculpta em todos os ecossistemas amostrados apresentando ampla distribuição geográfica. As análises histológicas revelaram que, aparentemente, estas metacercárias estavam alojadas por trás da retina. Os peixes menores do rio Taquari estavam menos parasitados por metacercárias do que os adultos. Esse padrão pode ser explicado pelo efeito cumulativo de parasitismo, evidenciado pela correlação positiva entre a abundância de metacercárias e tamanho do corpo dos peixes.

Monogeneans (Dactylogyridae) parasitizing gills of Salminus hilarii from a Neotropical reservoir, Brazil / Monogenéticos (Dactylogyridae) parasitando brânquias de Salminus hilarii de uma represa Neotropical, Brasil

With the aim of creating an inventory of the metazoan gill parasites of Salminus hilarii in the Taquari River, state of São Paulo, Brazil, five species of monogeneans (Anacanthorus contortus, A. bicuspidatus, Annulotrematoides parisellei, Jainus iocensis and Tereancistrum arcuatus) are reported the first time for this host. A total of 28 fish were sampled quarterly between April 2011 and January 2012, with 10 hosts in a lentic ecosystem and 18 in a lotic ecosystem. Quantitative ecological descriptors (prevalence, intensity of infestation and abundance) were calculated for the purpose to comparing the two ecosystems sampled (lentic and lotic ecosystems). However, no quantitative difference between the lentic and lotic ecosystems was observed. The present study has made available a checklist for species of the genus Anacanthorus and their hosts and geographical distribution in the Neotropical region up to the present time.

Com o objetivo de inventariar os metazoários parasitos de brânquias de Salminus hilarii do rio Taquari, estado de São Paulo, Brasil, cinco espécies de monogenéticos (Anacanthorus contortus, A. bicuspidatus, Annulotrematoides parisellei, Jainus iocensis, e Tereancistrum arcuatus) foram registradas pela primeira vez para o presente hospedeiro. Um total de 28 peixes foi amostrado trimestralmente entre abril/2011 e janeiro/2012, com 10 hospedeiros no ecossistema lêntico e 18 no ecossistema lótico. Os descritores ecológicos quantitativos (prevalência, intensidade de infestação e abundância) foram calculados com o objetivo de comparar os dois ecossistemas amostrados (ecossistema lêntico versus ecossistema lótico). No entanto, nenhuma diferença quantitativa desses foi verificada entre os ecossistemas lêntico e lótico. O presente estudo disponibiliza uma lista de espécies do gênero Anacanthorus, os hospedeiro e distribuição geográfica na região Neotropical até o presente momento.

Occurrence of Braga cigarra (Cymothoidae) parasitizing Galeocharax knerii (Characidae) from affluents of Jurumirim reservoir, Brazil / Ocorrência de Braga cigarra (Cymothoidae) parasitando Galeocharax knerii (Characidae) de afluentes da represa de Jurumirim, Brasil

The occurrence of the cymothoidae Braga cigarra is reported parasitizing the oral cavity of freshwater fish Galeocharax knerii from Veados, Paranapanema and Taquari Rivers, affluent of the Jurumirim Reservoir, State of São Paulo, Brazil is reported. The isopod species were identified based on the multilaminar pleopods, narrow pleon and short pleotelson in females. The overall prevalences of isopods were 31.7%, 7.7% and 5.7%, respectively, in the Paranapanema, Veados and Taquari Rivers. This note contributes to the knowledge of the geographical distribution and fauna of parasite crustaceans known to date in these important ecosystems.

Foi registrada a ocorrência do cymothoidae Braga cigarra parasitando a cavidade bucal do peixe de água doce Galeocharax knerii capturado nos rios Veados, Paranapanema e Taquari, afluentes da represa de Jurumirim, Estado de São Paulo, Brasil. As espécies de isópodas foram identificadas com base nos pleópodos multilaminares, abdômen estreito e pleotelson curto nas fêmeas. As prevalências totais de isópodos foram 31,7%, 7,7% e 5,7%, respectivamente, nos rios Paranapanema, Veados e Taquari. Essa nota contribui com o conhecimento da distribuição geográfica e da fauna de crustáceos parasitas conhecidas até a presente data nesses importantes ecossistemas aquáticos.

Occurrence of Braga cigarra (Cymothoidae) parasitizing Galeocharax knerii (Characidae) from affluents of Jurumirim reservoir, Brazil.

The occurrence of the cymothoidae Braga cigarra is reported parasitizing the oral cavity of freshwater fish Galeocharax knerii from Veados, Paranapanema and Taquari Rivers, affluent of the Jurumirim Reservoir, State of Sao Paulo, Brazil is reported. The isopod species were identified based on the multilaminar pleopods, narrow pleon and short pleotelson in females. The overall prevalences of isopods were 31.7%, 7.7% and 5.7%, respectively, in the Paranapanema, Veados and Taquari Rivers. This note contributes to the knowledge of the geographical distribution and fauna of parasite crustaceans known to date in these important ecosystems.

Monogeneans (Dactylogyridae) parasitizing gills of Salminus hilarii from a Neotropical reservoir, Brazil.

With the aim of creating an inventory of the metazoan gill parasites of Salminus hilarii in the Taquari River, state of São Paulo, Brazil, five species of monogeneans (Anacanthorus contortus, A. bicuspidatus, Annulotrematoides parisellei, Jainus iocensis and Tereancistrum arcuatus) are reported the first time for this host. A total of 28 fish were sampled quarterly between April 2011 and January 2012, with 10 hosts in a lentic ecosystem and 18 in a lotic ecosystem. Quantitative ecological descriptors (prevalence, intensity of infestation and abundance) were calculated for the purpose to comparing the two ecosystems sampled (lentic and lotic ecosystems). However, no quantitative difference between the lentic and lotic ecosystems was observed. The present study has made available a checklist for species of the genus Anacanthorus and their hosts and geographical distribution in the Neotropical region up to the present time.