Detection Of Amphibian Chytrid Fungus And Pest Risk Analysis(PRA) In China

Chytridiomycosis is one of the important infectious diseases of amphibians around the world since1998, it has been treated as the chief culprit of the animal extinction, which the humanity is experiencing at present, because it has led the extinction of nearly200species amphibians and the decline of amphibian populations of the half of the world. And because the chytrid fungus can spread through natural things like water, amphibians individuals, items which have been touched or trade around the world, the risk of chytrid fungus’spread is worsen greatly, the difficulty of the cross-border supervision and control also do so. It’s important to confirm the risk that our country is facing to about chytrid fungus. It has great significance for the health of amphibian populations, ecology and the trade of amphibians.This study is divided into2parts. The first chapter mainly analyzes the risk of domestic chytrid fungus in our country, to elevate the risk level of chytrid fungus in our country, making its contribution for ecological health around the world, as a responsible big country. For this goal, the epidemiological investigation method was adopted, combining with the characteristics of distribution and species of domestic amphibians and the introduction history of bullfrog to determine8regions of Heilongjiang, Sichuan, Yunnan, Guangxi, Hunan, Hubei, Anhui, Henan as sampling area, in which386individuals of5species of Rana chensinensis, Rana tigrina, Bufo bufo gargarizans cantor, Rana catesbeiana, Rana limnocharis were collected. The methods of cultivation, microscopy, histologic examination and molecular cloning were used to detect the chytrid fungus positive samples. In addition, the Loop-mediated isothermal amplification (LAMP) was also established which is suitable for the rapid and large area detection of chytrid fungus, and applying to the detection of samples. The suspected samples were rechecked by real-timeRT-PCR method to ensure that the specificity and sensitivity of detection. We didn’t find chytrid fungus in target region samples.The second chapter analyses the distribution of the global risk of amphibians and the risk level. This study is based on the industry standard of the People’s Republic of China Entry-Exit Inspection and Quarantine "Risk Analysis Procedure and Technique Requirement of Entry-Exit animals and animal products "(SN/T2486-2010) and New Zealand (BIOSECURITY NEW ZEALAND RISK ANALYSIS PROCEDURES Version1,12April2006):The potential import risk of chytrid fungus to China was analyzed by the incoming release probability, the possibility of contacting and the incoming consequences to make sure if it is quarantine pest, the possibility and the risk of incoming, and the qualitative expression of results. In particular, the release and contact exposure assessment comprehensive analysis table and consequences assessment comprehensive analysis table were used to obtain basic measurement data. By the analysis of release, exposure assessment, consequence assessment and release assessment, the probability of Chytrid fungus engraftment and spread, the risk evaluation and risk grading of amphibian chytrid fungus in export countries in each continent, the risk of chytrid fungus output from each continent of the world to our country was reached by the integration of the continents’risk. The research showed that our country facing the global chytrid fungus risk level is "Medium".Through the research we may draw the conclusion:1.The risk of amphibian chytrid fungus in China is low temporarily, and the main risk is from the external world of international trade.2.China is facing the huge external risk pressure of imported amphibian chytrid fungus which is in urgent need to enhance the import management strictly to protect amphibian species in our country, ecological safety and the aquaculture and trade of amphibians.3.There are more than40kinds of aquatic species are susceptible to chytrid fungus with a close relationship to economic development. We suggest to enhance the relevant activities of legislation and regulation enforcement.