RESUMO
Ranaviruses can cause mass mortality events in amphibians, thereby becoming a threat to populations that are already facing dramatic declines. Ranaviruses affect all life stages and persist in multiple amphibian hosts. The detrimental effects of ranavirus infections to amphibian populations have already been observed in the UK and in North America. In Central and South America, the virus has been reported in several countries, but the presence of the genus Ranavirus (Rv) in Colombia is unknown. To help fill this knowledge gap, we surveyed for Rv in 60 species of frogs (including one invasive species) in Colombia. We also tested for co-infection with Batrachochytrium dendrobatidis (Bd) in a subset of individuals. For Rv, we sampled 274 vouchered liver tissue samples collected between 2014 and 2019 from 41 localities covering lowlands to mountaintop páramo habitat across the country. Using quantitative polymerase chain reaction (qPCR) and end-point PCR, we detected Rv in 14 individuals from 8 localities, representing 6 species, including 5 native frogs of the genera Osornophryne, Pristimantis and Leptodactylus, and the invasive American bullfrog Rana catesbeiana. Bd was detected in 7 of 140 individuals, with 1 co-infection of Rv and Bd in an R. catesbeiana specimen collected in 2018. This constitutes the first report of ranavirus in Colombia and should set off alarms about this new emerging threat to amphibian populations in the country. Our findings provide some preliminary clues about how and when Rv may have spread and contribute to understanding how the pathogen is distributed globally.
Assuntos
Anfíbios , Infecções por Vírus de DNA , Ranavirus , Animais , Anfíbios/microbiologia , Anfíbios/virologia , Anuros/microbiologia , Anuros/virologia , Batrachochytrium/fisiologia , Coinfecção/veterinária , Colômbia/epidemiologia , Infecções por Vírus de DNA/complicações , Infecções por Vírus de DNA/epidemiologia , Infecções por Vírus de DNA/veterinária , Micoses/complicações , Micoses/veterinária , Rana catesbeiana/microbiologia , Rana catesbeiana/virologia , Ranavirus/fisiologiaRESUMO
Atelognathus patagonicus is an endangered leptodactylid frog endemic to a small region in and around Laguna Blanca National Park in northern Patagonia, Argentina. All of the lakes and small ponds of the region (except Laguna Blanca itself) contain A. patagonicus and in all but one of these lakes the species shows clinical signs of a previously undiagnosed disease, the characteristics of which suggested a ranavirus. We collected symptomatic and asymptomatic A. patagonicus frogs and tadpoles from 4 small lakes and analyzed tissues for ranavirus and the chytrid fungus Batrachochytrium dendrobatidis using PCR amplification of pathogen DNA. Of the 32 specimens tested, 25 were positive for ranavirus major capsid protein (MCP). Sequence alignments of the ranavirus MCP from these specimens showed 100% similarity with published FV3 and FV3-like viruses from anurans, 98 to 99 % similarity with Bohle iridovirus, and 95 % similarity with Ambystoma tigrinum virus (ATV) and Regina ranavirus (RRV). A search of the NCBI Blast nucleotide database using the 500 base pair MCP sequence obtained from these samples did not suggest any homology to any other pathogen. In addition, 1 sample (3 pooled individuals) from 1 lake tested positive for B. dendrobatidis. The clinical signs observed primarily in late-stage tadpoles and recent metamorphs, which have reoccurred each year since at least 2001, are consistent with ranaviral disease, but until histopathology of diseased individuals is carried out, chytridiomycosis or other diseases cannot be ruled out.
Assuntos
Anuros/virologia , Infecções por Vírus de DNA/veterinária , Ranavirus/isolamento & purificação , Animais , Proteínas do Capsídeo/genética , Quitridiomicetos/isolamento & purificação , Infecções por Vírus de DNA/complicações , Infecções por Vírus de DNA/epidemiologia , Infecções por Vírus de DNA/virologia , Micoses/complicações , Micoses/veterinária , Reação em Cadeia da Polimerase/veterinária , Ranavirus/genética , América do SulRESUMO
The objective was to study Orthomyxovirus in heterothermic animals. Blood samples from snakes (genus Bothrops and Crotalus) and from toads and frogs (genus Bufo and Rana) were collected to evaluate the red cell receptors and antibodies specific to influenza virus by the hemagglutination and hemagglutination inhibition tests, respectively. Both snakes and toads kept in captivity presented receptors in their red cells and antibodies specific to either influenza virus type A (human and equine origin) or influenza type B. The same was observed with recently captured snakes. Concerning the influenza hemagglutination inhibition antibodies protective levels were observed in the reptiles' serum, against influenza type A and type B. Unlike the toads, 83.3% of the frogs presented mean levels of Ab 40HIU for some influenza strains. It was concluded that heterothermic animals could offer host conditions to the influenza virus and also susceptibility to the infection.
Assuntos
Alphainfluenzavirus/isolamento & purificação , Anticorpos Antivirais/sangue , Anuros/virologia , Betainfluenzavirus/isolamento & purificação , Viperidae/virologia , Animais , Testes de Inibição da Hemaglutinação , Alphainfluenzavirus/imunologia , Betainfluenzavirus/imunologiaRESUMO
Blood erythrocytes of Brazilian tree-frogs, Phrynohyas venulosa were found to frequently contain single, small, densely staining inclusions. Electron microscopy showed these to be icosahedral viral particles which measured from 250-280 nm in diameter: they were devoid of an envelope, and thus differed from previously described viruses of frog erythrocytes. The infected erythrocytes lacked a crystalline body.