First parasitological study of the African clawed frog (Xenopus laevis, Amphibia) in Chile / Primeiro estudo parasitológico em rã com garras Africano (Xenopus laevis, Anfibia) no Chile

Introduced species can arrive into new territories with parasites; however, these species are expected to face lower parasite richness than in their original regions. Both introduced hosts and parasites can affect native fauna. Since their release into the wild in Chile following laboratory use, Xenopus laevis Daudin, 1802 has widely spread throughout central Chile. The only pathogen described on the host is the fungus Batrachochytrium dendrobatidis Longcore, Pessier, Nichols, 1999; thus, this is the first parasitological study of this species in Chile. In 10 localities in central Chile, 179 specimens of X. laevis were captured and examined for parasites in the gastrointestinal tube, cavities, lungs, liver, and skin. Only nine specimens of the genus Contracaecum Railliet, Henry, 1912 were found in six specimens of X. laevis from a private dam in La Patagua. It is likely that these parasites originated from species of native birds. This is the first record of Contracaecum sp. in Chilean amphibians.(AU)

Espécies exóticas podem se introduzir em um novo território com seus parasitas, porém nesses casos, a riqueza parasitária seria menor. Contudo, hospedeiros exóticos e seus parasitas associados podem afetar a fauna nativa. Depois de ser dispensado do uso em laboratórios e solto em ambientes naturais, Xenopus laevis Daudin, 1802 tem se espalhado massivamente no Chile central. O único patógeno descrito para este anuro é o fungo Batrachochytrium dendrobatidis Longcore, Pessier, Nichols, 1999. O presente estudo constitui a primeira pesquisa parasitológica realizada nesta espécie de rã introduzida no Chile. Em 10 localidades do Chile central, foram capturados 179 espécimes de X. laevis que foram examinadas em busca de parasitos dentro tubo digestivo, cavidades corporais, pulmões, fígado e pele. Nove espécimes do gênero Contracaecum Railliet, Henry, 1912 foram encontrados em seis espécimes de X. laevis de uma barragem em La Patagua. É provável que a origem destes parasitas sejam espécies de aves nativas. Este é o primeiro relato de Contracaecum sp. em anuros do Chile.(AU)

The use of singleplex and nested PCR to detect Batrachochytrium dendrobatidis in free-living frogs

Many microorganisms are able to cause diseases in amphibians, and in the past few years one of the most reported has been Batrachochytrium dendrobatidis. This fungus was first reported in Brazil in 2005; following this, other reports were made in specimens deposited in museum collections, captive and free-living frogs. The aim of this study was to compare singleplex and nested-PCR techniques to detect B. dendrobatidis in free-living and apparently healthy adult frogs from the Brazilian Atlantic Forest. The sample collection area was a protected government park, with no general entrance permitted and no management of the animals there. Swabs were taken from the skin of 107 animals without macroscopic lesions and they were maintained in ethanol p.a. Fungal DNA was extracted and identification of B. dendrobatidis was performed using singleplex and nested-PCR techniques, employing specific primers sequences. B. dendrobatidis was detected in 61/107 (57%) and 18/107 (17%) animals, respectively by nested and singleplex-PCR. Nested-PCR was statistically more sensible than the conventional for the detection of B. dendrobatidis (Chi-square = 37.1; α = 1%) and the agreement between both techniques was considered just fair (Kappa = 0.27). The high prevalence obtained confirms that these fungi occur in free-living frogs from the Brazilian Atlantic Forest with no macroscopic lesions, characterizing the state of asymptomatic carrier. We concluded that the nested-PCR technique, due to its ease of execution and reproducibility, can be recommended as one of the alternatives in epidemiological surveys to detect B. dendrobatidis in healthy free-living frog populations.(AU)

Body length of Hylodes cf. ornatus and Lithobates catesbeianus tadpoles, depigmentation of mouthparts, and presence of Batrachochytrium dendrobatidis are related / Tamanho do corpo, despigmentação das partes bucais e presença de Batrachochytrium dendrobatidis estão relacionados em Hylodes cf. ornatus e Lithobates catesbeianus

A fungal pathogen Batrachochytrium dendrobatidis (Bd), which can cause morbidity and death of anurans, has affected amphibian populations on a worldwide basis. Availability of pure cultures of Bd isolates is essential for experimental studies to understand the ecology of this pathogen. We evaluated the relationships of body length of Hylodes cf. ornatus and Lithobates catesbeianus tadpoles to depigmentation of mouthparts and determined if dekeratinization indicated an infection by Batrachochytrium dendrobatidis. A strong association existed for both species, one from South America (Brazil: São Paulo) and one from North America (USA: Maine). We believe it prudent not to kill adult amphibians if avoidable, thus obtaining tissue for isolating Bd from tadpoles is reasonable because infected specimens of some species can be selectively collected based on depigmentation of mouthparts.(AU)

O fungo patógeno Batrachochytrium dendrobatidis (Bd) é apontado como o causador de morbidade e morte em anuros, e tem afetado populações de anfíbios em uma base mundial. Avaliar culturas puras de isolados de Bd é essencial para estudos experimentais para o entendimento da ecologia desse patógeno. Avaliou-se a relação entre o comprimento do corpo em girinos de Hylodes cf. ornatus e Lithobates catesbeianus com a despigmentação das peças bucais, para verificar se a desqueratinização indica uma infecção por Batrachochytrium dendrobatidis. Uma forte associação existe para ambas as espécies, uma da América do Sul (Brasil: São Paulo) e uma da América do Norte (USA: Maine). Acredita-se ser prudente este uso, para evitar a morte de anfíbios adultos; dessa forma, obter tecidos para isolar o Bd de girinos é razoável, porque espécimes infectados podem ser coletados seletivamente com base na despigmentação do aparelho bucal.(AU)

Chytridiomycosis: a Devastating Emerging Fungal Disease of Amphibians

Amphibians have suffered the most striking declines among all vertebrates. Infectious diseases are one of the causes and Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd) is considered the most concerning one. This emerging infectious disease infects a broad variety of amphibians and is considered responsible for numerous declines and extinctions of these animals. Bd has been reported all over the world including Brazil in captive and free living species of amphibians. The origin of this pan-epizootic is unkown. Major histopathological findings include epidermal hyperkeratosis, hyperplasia, and focal necrosis of epidermal cells. The cause of death may be by disruption of ion equilibrium. The chytrid infection may be diagnosed with methods such as histopathology, immunohistochemistry, electron microscopy, conventional PCR, real-time PCR, and nested PCR. The most used treatment is daily baths of itraconazole at 0.01% for five minutes during 11 days. This has been successfully used to treat chytridiomycosis in a few amphibian species. Disinfection protocols are essential for the management of chytridiomycosis in captivity and in the wild. This is an important disease to be studied in Brazil due to the devastating effects that it can cause in amphibians populations.(AU)

Patologia comparada de infecções selecionadas de anfíbios anuros de vida livre do bioma da Mata Atlântica: estudo prospectivo / Comparative pathology of selected infections of free living anuran amphibians from the Atlantic Forest biome: prospective study

Os anfíbios apresentaram um severo declínio de suas populações nas últimas décadas. Dentre as diversas causas dos declínios estão as doenças infecciosas. O presente trabalho tem o objetivo de estudar a ocorrência de enfermidades selecionadas que podem acometer estes animais na Mata Atlântica brasileira, e, desta forma, contribuir para a melhor compreensão das conseqüências destas enfermidades para a conservação dos anfíbios em nosso meio. Foram coletados 120 animais da Estação Biológica da Boracéia e realizaram-se exames necroscópicos, histopatológicos, microbiológicos, parasitológicos e PCR convencional para Batrachochytrium dendrobatidis em grande parte dos animais. Coletou-se 33 espécies diferentes pertencentes a sete famílias diferentes. Encontrou-se, no exame necroscópico, endoparasitas em 45,8% (55/120) dos espécimes examinados e ectoparasita (sanguessuga) em um espécime. Do total de animais analisados para Batrachochytrium dendrobatidis, 19,1% (22/115) foram positivos para Bd. O exame necroscópico assim como o histopatologicos da grande maioria dos animais estudados não exibiu alterações relevantes, sendo que os sistemas mais acometidos foram o digestório e tegumentar seguidos pelos urinário e linfóide. A somatória dos resultados aqui exibidos sugere que, nas condições específicas deste trabalho, os agentes identificados não induziram processos patológicos relevantes, sinalizando uma relação hospedeiro x parasita simétrica. Porém, face ao frágil equilíbrio existente no ambiente da Mata Atlântica e a suscetibilidade dos anfíbios às mudanças dos ecossistemas, cremos que monitoramentos de longo prazo sejam necessários para que se possa acompanhar, com alguma margem de segurança, a evolução desta delicada relação

Amphibians suffered a severe decline of their populations in recent decades. Among the various causes of the declines are infectious diseases. The present work aims to study the occurrence of selected diseases that can affect these animals in the Brazilian Atlantic Forest, and thus contribute to a better understanding of the consequences of these diseases for the conservation of these animals. We collected 120 animals from the Biological Station of Boracéia and performed necropsy, histopathology, microbiology, parasitology and conventional PCR for Batrachochytrium dendrobatidis exams in most animals. We collected 33 different species belonging to seven different families. It was found at necropsy, endoparasites in 45.8% (55/120) of specimens examined and an ectoparasite in only one specimen. Of the total number of animals analyzed for Batrachochytrium dendrobatidis, 19.1% (22/115) were positive for this fungus. The necropsy and histopathological exams from the vast majority of animals studied did not show significant changes. The most affected systems were the digestive and integumentary followed by the lymphoid and urinary. The results shown in this work suggests that the infections agents did not induce relevant pathological processes in the specific conditions of this research. However, given the fragile balance of the Atlantic Forest and the susceptibility of amphibians to ecosystem change, we believe that long-term monitoring is needed to follow with some safety margin, the evolution of this delicate relationship

Chytridiomycosis: a devastating emerging fungal disease of amphibians

Amphibians have suffered the most striking declines among all vertebrates. Infectious diseases are one of the causes and Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd) is considered the most concerning one. This emerging infectious disease infects a broad variety of amphibians and is considered responsible for numerous declines and extinctions of these animals. Bd has been reported all over the world including Brazil in captive and free living species of amphibians. The origin of this pan-epizootic is unkown. Major histopathological findings include epidermal hyperkeratosis, hyperplasia, and focal necrosis of epidermal cells. The cause of death may be by disruption of ion equilibrium. The chytrid infection may be diagnosed with methods such as histopathology, immunohistochemistry, electron microscopy, conventional PCR, real-time PCR, and nested PCR. The most used treatment is daily baths of itraconazole at 0.01% for five minutes during 11 days. This has been successfully used to treat chytridiomycosis in a few amphibian species. Disinfection protocols are essential for the management of chytridiomycosis in captivity and in the wild. This is an important disease to be studied in Brazil due to the devastating effects that it can cause in amphibians populations.