O objetivo do trabalho foi realizar investigação sobre ocorrência de ranavirose, infecção causada por vírus do gênero Ranavirus, família Iridoviridiae, em anfíbios anuros silvestres nos municípios de Porto Ferreira e Pirassununga, cidades da região centro-leste do estado de São Paulo, Brasil, utilizando diagnóstico molecular. Ao todo, 40 anuros adultos silvestres da espécie Leptodactylus fuscus foram capturados nos municípios citados, sendo coletados três órgãos alvos (fígado, baço e rins) de replicação viral, com registro de eventuais alterações macroscópicas nesses órgãos, e dos quais extraiu-se DNA. Na sequência, realizou a reação em cadeia pela polimerase (PCR), utilizando-se primers específicos para o gene MCP (major capsid protein) de Frog Virus 3 (FV3), ranavírus circulante no Brasil, com isolado de FV3 pertencente ao biobanco do Laboratório de Higiene Zootécnica da FZEA-USP empregado como controle positivo e água livre de nuclease como controle negativo. Como resultados, em relação às alterações macroscópicas, somente um espécime apresentou hepatoesplenomegalia e hipopigmentação do coração. No entanto, ao diagnóstico molecular, nenhum dos 40 animais amostrados foi positivo à ranavirose. Tal resultado pode estar associado tanto a fatores intrínsecos (espécie, idade, resposta imune) como extrínsecos ao hospedeiro (alterações ambientais, patogenicidade viral). Em paralelo, em rãs de criação comercial, surtos por FV3 já foram detectados em vários ranários do país; contudo, essa é a primeira vez que uma prospecção para ranavirose é realizada especificamente com representantes da espécie Leptodactylus fuscus, em municípios da região centro-leste do estado de São Paulo. Assim, são necessárias mais pesquisas com espécies silvestres de rãs, particularmente no entorno de ranários com histórico de animais positivos para FV3, para melhor conhecimento da epidemiologia e dinâmica de transmissão da ranavirose entre rãs silvestres. / The objective of this study was to investigate the occurrence of ranavirus infection caused by virus belonging to genus Ranavirus, Iridoviridiae family, in wild anuran amphibians from Porto Ferreira and Pirassununga municipalities, located in the central-eastern region of the state of São Paulo, Brazil, using molecular diagnostics. In all, 40 wild adult anurans of the species Leptodactylus fuscus were captured in the mentioned municipalities, and three target organs (liver, spleen and kidneys) of the viral replication were collected, being possible macroscopic changes in these organs recorded, and from which DNA was extracted. In the sequence, the polymerase chain reaction (PCR) was carried out using primers specific for the MCP (major capsid protein) gene of Frog Virus 3 (FV3), a circulating ranavirus in Brazil, with a FV3 isolate belonging to the biobank of the Laboratory of Zootechnical Hygiene of FZEA-USP employed as positive control and nuclease-free water as negative control. As a result, in relation to macroscopic alterations, only one specimen showed hepatosplenomegaly and heart hypopigmentation. However, for molecular diagnostics, none of the 40 animals sampled were positive for ranavirus. This result may be associated to both intrinsic (species, age, immune response) and extrinsic (environmental changes, viral pathogenicity) factors to the host. In parallel, FV3 outbreaks have already been detected in several frog farms in the country. However, this is the first time that a prospection for ranavirus infection is performed specifically with specimens of the Leptodactylus fuscus from municipalities in the central-eastern region of the state of São Paulo. Thus, more studies on wild-type frogs are needed, particularly in the settings of frog farms with positive animal history for FV3, to better understand the epidemiology and dynamics of ranavirus transmission among wild frogs.

Algumas doenças associadas à piscicultura de tilápias trazem enormes prejuízos aos criadores, resultando em expressivos coeficientes de morbidade e mortalidade entre animais de todas as idades. Nesse sentido, exigências para o aprimoramento do diagnóstico laboratorial de doenças de natureza infecto-contagiosa tornaram-se constantes, face às perdas vinculadas. Os Ranavirus são vírus que infectam vertebrados ectotérmicos causando necrose generalizada, hemorragias focais e apoptose celular nos animais infectados. O presente estudo objetivou a realização de infecções experimentais em larvas e alevinos de tilápia do Nilo (Oreochromis niloticus), através de 3 diferentes modelos de infecção, utilizando estirpe de Ranavirus Frog vírus 3-like; recentemente detectada e isolada no Brasil, para avaliação das patologias associadas, incluindo o sequenciamento e análise do genoma da cepa viral. Vários sinais clínicos macroscópicos e microscópicos foram observados, hemólise, hemácias com anisocitose e policromasia, alterações relacionadas a média dos volumes das hemácias e hemoglobina, índices hepato-somáticos e espleno-somáticos com interações estatisticamente significantes, linfócitos reativos, alterações nos níveis das enzimas alanina aminotransferase e corpúsculos de inclusão basofílicos em diferentes tecidos dos animais experimentados com Ranavirus FV3-like foram observados dentro do período de 60 dias pós-infecção. Além disso, animais experimentalmente infectados foram positivos ao Ranavirus através de qPCR. O genoma de cepa brasileira de Ranavirus FV3-like apresentou 105 kilobases, contendo 54,98% de guanina + citosina, sendo 94 potenciais ORFs anotadas. A reconstrução filogenética, baseada em sequencias nucleotídicas, agrupou a amostra brasileira de Ranavirus no clado dos Frog vírus 3-like e as maiores identidades do genoma se deram com cepas norte-americanas de FV3-like. Doze potenciais eventos de recombinação, estatisticamente significantes (p < 0,05), foram identificados entre a cepa brasileira e amostras de referência de Ranavirus FV3-like. Nesse sentido, o presente trabalho contribui para o melhor entendimento da infecção causada por estirpe brasileira de Ranavirus FV3-like em tilápias do Nilo (Oreochromis niloticus). Além disso, adiciona e reforça a potencial recombinação entre diferentes estirpes de Ranavirus, colaborando para uma melhor compreensão das características de agentes virais associados a graves surtos em vertebrados ectotérmicos no país. / Some diseases associated with tilapia fish farming cause enormous losses to breeders, resulting in significant morbidity and mortality rates among animals of all ages. In this sense, requirements for the improvement of the laboratory diagnosis of diseases of infectious-contagious nature, became constant, in view of the related losses. Ranaviruses are viruses that infect ectothermal vertebrates causing widespread necrosis, focal haemorrhages and cell apoptosis in infected animals. The present study aimed to perform experimental infections in Nile tilapia (Oreochromis niloticus) fry and larvae through 3 different infection models, using Ranavirus Frog virus 3-like strain recently detected and isolated in Brazil, to evaluate the associated pathologies, including sequencing and genome analysis of the viral strain. Several macroscopic and microscopic clinical signs were observed, hemolysis, red blood cells presenting anisocytosis and polychromasia, alterations related to the mean red blood cell volumes and hemoglobin present in the red blood cells, hepato-somatic and spleno-somatic indexes showing statistically significant interactions, reactive lymphocytes, alterations in the levels of the enzymes alanine aminotransferase and basophilic inclusion corpuscles in different tissues of animals tested with Ranavirus FV3-like were observed within the 60-day post-infection period. In addition, experimentally infected animals were positive to Ranavirus through qPCR. The genome of the Ranavirus FV3-like Brazilian strain presented 105 kilobases, containing 54.98% of guanine + cytosine, with 94 potential ORFs annotated. The phylogenetic reconstruction, based on nucleotide sequences, grouped the Brazilian sample of Ranavirus in the clade of Frog virus 3-like, the greater identities of the genome were with North American strains of FV3-like. Twelve potential recombination events, statistically significant (p <0.05), were identified between the Brazilian strain and reference samples of Ranavirus FV3-like. The present work contributes to a better understanding of the infection caused by the Brazilian strain of Ranavirus FV3-like in Nile tilapia (Oreochromis niloticus). In addition, it adds and reinforces the potential recombination between different strains of Ranavirus, contributing to a better understanding of the characteristics of viral agents associated with severe outbreaks in ectothermic vertebrates.

<p>Dispersal is an important factor in animal ecology. Anurans (frogs and toads) are often philopatric (home loving) but some specimens in a population usually have the capacity to disperse relatively long distances. In this study I investigated the colonization of newly constructed ponds in the southwest of Sweden by three anuran species: The common toad (Bufo bufo), the moor frog (Rana arvalis) and the common frog (Rana temporaria). The ponds were constructed between two and five years ago and were now as frequently occupied as older source ponds in the area. For the common toad and the common frog there was no correlation between distance to source populations and degree of colonization. The moor frog was more common in ponds that were situated in the vicinity of older source ponds with ample populations. The main impression was that these species rapidly colonize newly constructed ponds, at least within moderate distances from source populations. There were some differences between the species though and it seems like the moor frog have more limited dispersal abilities than the other two species.</p>

Dispersal is an important factor in animal ecology. Anurans (frogs and toads) are often philopatric (home loving) but some specimens in a population usually have the capacity to disperse relatively long distances. In this study I investigated the colonization of newly constructed ponds in the southwest of Sweden by three anuran species: The common toad (Bufo bufo), the moor frog (Rana arvalis) and the common frog (Rana temporaria). The ponds were constructed between two and five years ago and were now as frequently occupied as older source ponds in the area. For the common toad and the common frog there was no correlation between distance to source populations and degree of colonization. The moor frog was more common in ponds that were situated in the vicinity of older source ponds with ample populations. The main impression was that these species rapidly colonize newly constructed ponds, at least within moderate distances from source populations. There were some differences between the species though and it seems like the moor frog have more limited dispersal abilities than the other two species.

Although the range dynamics of North American amphibians during the last glacial cycle are increasingly better understood, the recolonization history of the most northern regions and the impact of southern refugia on patterns of genetic diversity in these regions are not well reconstructed. In this study I present the phylogeographic history of a widespread and primarily northern frog, Rana sylvatica. For this study, 45 individuals from 34 localities were surveyed for a 700 b p. fragment of cytochrome b and 551 individuals from 116 localities were surveyed for 650 b.p. of the NADH dehydrogenase subunit 2 and tRNATRP mitochondrial genes. Phylogenetic analyses revealed two distinct clades corresponding to eastern and western populations. Phylogeographic patterns within each of these clades revealed similarities as well as differences from patterns found in other species. Specifically, the results corroborate eastern refugia located in the southern Appalachians near present-day North and South Carolina and in the interior plains in the lower Ohio River Valley. Current Maritime populations form a subclade amongst eastern populations and appear to have been colonized from the southern refugium. However, a more northern refugium located in the Appalachian highlands seems to have been source for most other northeastern wood frog populations. Rana sylvatica populations in the Great Lakes region appear to have been colonized from a western refugium located in present-day Wisconsin. This refugium was also a likely source for populations in the species' expansive northwestern range since there is no evidence to support additional, more western refugia.

Thesis (M.S.)--Miami University, Dept. of Zoology, 2007. / Title from first page of PDF document. Includes bibliographical references (p. 17-19).

Thesis (Ph. D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on June 11, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Environmental Biology and Ecology, Department of Biological Sciences, University of Alberta. Includes bibliographical references.

Thesis (M.S.)--Humboldt State University, 2009. / Includes bibliographical references (leaves 44-46). Also available via Humboldt Digital Scholar.

O objetivo do trabalho foi realizar investigação sobre ocorrência de ranavirose, infecção causada por vírus do gênero Ranavirus, família Iridoviridiae, em anfíbios anuros silvestres nos municípios de Porto Ferreira e Pirassununga, cidades da região centro-leste do estado de São Paulo, Brasil, utilizando diagnóstico molecular. Ao todo, 40 anuros adultos silvestres da espécie Leptodactylus fuscus foram capturados nos municípios citados, sendo coletados três órgãos alvos (fígado, baço e rins) de replicação viral, com registro de eventuais alterações macroscópicas nesses órgãos, e dos quais extraiu-se DNA. Na sequência, realizou a reação em cadeia pela polimerase (PCR), utilizando-se primers específicos para o gene MCP (major capsid protein) de Frog Virus 3 (FV3), ranavírus circulante no Brasil, com isolado de FV3 pertencente ao biobanco do Laboratório de Higiene Zootécnica da FZEA-USP empregado como controle positivo e água livre de nuclease como controle negativo. Como resultados, em relação às alterações macroscópicas, somente um espécime apresentou hepatoesplenomegalia e hipopigmentação do coração. No entanto, ao diagnóstico molecular, nenhum dos 40 animais amostrados foi positivo à ranavirose. Tal resultado pode estar associado tanto a fatores intrínsecos (espécie, idade, resposta imune) como extrínsecos ao hospedeiro (alterações ambientais, patogenicidade viral). Em paralelo, em rãs de criação comercial, surtos por FV3 já foram detectados em vários ranários do país; contudo, essa é a primeira vez que uma prospecção para ranavirose é realizada especificamente com representantes da espécie Leptodactylus fuscus, em municípios da região centro-leste do estado de São Paulo. Assim, são necessárias mais pesquisas com espécies silvestres de rãs, particularmente no entorno de ranários com histórico de animais positivos para FV3, para melhor conhecimento da epidemiologia e dinâmica de transmissão da ranavirose entre rãs silvestres. / The objective of this study was to investigate the occurrence of ranavirus infection caused by virus belonging to genus Ranavirus, Iridoviridiae family, in wild anuran amphibians from Porto Ferreira and Pirassununga municipalities, located in the central-eastern region of the state of São Paulo, Brazil, using molecular diagnostics. In all, 40 wild adult anurans of the species Leptodactylus fuscus were captured in the mentioned municipalities, and three target organs (liver, spleen and kidneys) of the viral replication were collected, being possible macroscopic changes in these organs recorded, and from which DNA was extracted. In the sequence, the polymerase chain reaction (PCR) was carried out using primers specific for the MCP (major capsid protein) gene of Frog Virus 3 (FV3), a circulating ranavirus in Brazil, with a FV3 isolate belonging to the biobank of the Laboratory of Zootechnical Hygiene of FZEA-USP employed as positive control and nuclease-free water as negative control. As a result, in relation to macroscopic alterations, only one specimen showed hepatosplenomegaly and heart hypopigmentation. However, for molecular diagnostics, none of the 40 animals sampled were positive for ranavirus. This result may be associated to both intrinsic (species, age, immune response) and extrinsic (environmental changes, viral pathogenicity) factors to the host. In parallel, FV3 outbreaks have already been detected in several frog farms in the country. However, this is the first time that a prospection for ranavirus infection is performed specifically with specimens of the Leptodactylus fuscus from municipalities in the central-eastern region of the state of São Paulo. Thus, more studies on wild-type frogs are needed, particularly in the settings of frog farms with positive animal history for FV3, to better understand the epidemiology and dynamics of ranavirus transmission among wild frogs.

No description available.