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Health assessment in Madagascar : invasive asian toad (Duttaphrynus melanostictus) as a vector for emerging pathogens

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Resumo:Recently, the Asian common toad Duttaphrynus melanostictus arrived in Madagascar, presenting a high expansion rate. Besides the high fertility rate and toxins, it’s likely that these toads may be infected with different pathogenic agents, posing a threat to the Malagasy species. This study meets the need to identify which infectious agents are present, and if these toads are a real threat to the ecosystem. Asian toads (n=110) were caught, close to the Toamasina port (Madagascar), euthanized, and the liver and skin were collected and preserved in 98% ethanol. The sample collection took place during the dry season (July 2014) and the rainy season (March 2015). The toads were tested for the presence of chytrid fungus (Batrachochytrium dendrobatidis), Ranavirus, chlamydia, Herpesvirus and Salmonella. The first two are emerging infectious pathogens: chytrid leads to chytridiomycosis and the second is an Iridovirus responsible for ranaviral disease. Both are considered the two major diseases leading to amphibian declines and extinctions. The Ranavirus screening detected 10 positive samples in the dry season, and none in the rainy season. 9 positive samples to Chlamydiaceae in the dry season and 2 in the rainy season. No sample was positive to chytrid or Herpesvirus. Salmonella PCR detected only one positive in the dry season.
Autores principais:Félix, Inês Alvito
Assunto:Madagascar Duttaphrynus melanostictus Chytridiomycosis Ranavirus Chlamydiaceae Salmonella Quitridiomicose
Ano:2016
País:Portugal
Tipo de documento:dissertação de mestrado
Tipo de acesso:acesso aberto
Instituição associada:Universidade de Lisboa
Idioma:inglês
Origem:Repositório da Universidade de Lisboa
Descrição
Resumo:Recently, the Asian common toad Duttaphrynus melanostictus arrived in Madagascar, presenting a high expansion rate. Besides the high fertility rate and toxins, it’s likely that these toads may be infected with different pathogenic agents, posing a threat to the Malagasy species. This study meets the need to identify which infectious agents are present, and if these toads are a real threat to the ecosystem. Asian toads (n=110) were caught, close to the Toamasina port (Madagascar), euthanized, and the liver and skin were collected and preserved in 98% ethanol. The sample collection took place during the dry season (July 2014) and the rainy season (March 2015). The toads were tested for the presence of chytrid fungus (Batrachochytrium dendrobatidis), Ranavirus, chlamydia, Herpesvirus and Salmonella. The first two are emerging infectious pathogens: chytrid leads to chytridiomycosis and the second is an Iridovirus responsible for ranaviral disease. Both are considered the two major diseases leading to amphibian declines and extinctions. The Ranavirus screening detected 10 positive samples in the dry season, and none in the rainy season. 9 positive samples to Chlamydiaceae in the dry season and 2 in the rainy season. No sample was positive to chytrid or Herpesvirus. Salmonella PCR detected only one positive in the dry season.