Spatial Distributional Predictions For Trypanosoma And Hepatozoon In Anura Species In China By MAXENT Model

It is recorded in the most important traditional Chinese medicine classics’Huang Di Nei Jing’that the saint prefers preventing diseases and disorders rather than treating them.Low capability of immunity, the invasion of pathogens and uneven environmental factors etc., all can lead to diseases. The natural geographical environmental factors provide the basic conditions for its growth and reproduction of each organism, but also coordinate and restrict its development. In diseases prevention, besides immunity resistance enhancement, pathogens’ transmission cutting off and pathogens elimination, the environmental factors should also be considered. Therefore, this project will mainly use the environment variables? combined the different geographic coordinates, which has been reported, to make the spatial distribution prediction for two parasite diseases.Trypanosomes and Hepatozoon are two main diseases burden of amphibians, which can be widely disseminated to vertebrates by the media insects to invade the animal body, distroy the physiological functions of red and white blood cells, which could ultimately affect the body’s health and even threat animals’lifes. In addition, there are a great amount of species of media insects of Trypanosoma and Hepatozoon including reduviidae, leeches, culex and so on. At the same time, the fecundity and survival rates of these insects are particularly strong, so it’s difficulty to control the hosts.In recent years, amphibians have been the one of the focus in the objectives of Conservation Union (IUCN) Red Data Book. The diseases as one reason of risk factor which make amphibians facing extinction has been widespread concerned.Currently, Chinese scholars has not yet reported their study about amphibians infected with trypanosomes and Hepatozoon, while foreign researchers have begun their phylogenetic study in this filed. Therefore, this project aims to to predict varying degrees of regional risk of these diseases globally and domesticly especially by MAXENT technology combining the reported geographical coordinates and environmental factors.In addition, blood smear and PCR technologies were used to detect trypanosomes and Hepatozoon in three kinds of amphibians from China’s Changbai Mountains Nature Reserve, and compare test results with that by MAXENT model. Which would provide reference for spatial risk prediction in the investigations of the trypanosomes and Hepatozoon in the future in our country.Methods:1. Possible regions prediction with Trypanosomes and Hepatozoon infection in amphibians in China by MAXENT:reported geographical coordinates related to trypanosomes and Hepatozoon infection were integrated by extensive literature review. Selected environmental factors variables (maximum temperature, minimum temperature, mean temperature, precipitation and altitude) were entered into the DIVA-GIS and then conversed the file format. According to the provision edition, upper data were entered into the specified software to process and obtain the possible spatial distributional maps of the two diseases worldwide;2. Blood smears’check by microscopy in laboratory;3.PCR assay for target parasites of the blood samples of Rana dybowskii, Rana nigromaculat and Bufo bufogargarizans Cantor from Changbai Mountains Nature Reserve in Jilin Province. Tested gene’s fragments were confirmed by DNA fragments amplification, electrophoresis, cloning and sequences analysis by Shanghai Invitrogen Co. Ltd. BLAST analysis were done in the NCBI web site online.4. Comparision of the results of blood smear test, PCR test and MAXENT, and then verifing if the results are exactly consistent with the conclusion of the forecast map.Results:(1) Results indicated that the Trypanosomes and Hepatozoon of amphibians were mainly distributed around water-rich regions in the global scale. In China, the highly suitable areas of Trypanosom and Hepatozoon are mainly concentrated in the Basins of Yangtze River and the the Yellow River; the moderate risk regions of Hepatozoon is located at the downstream of the Yangtse River, Hainan Island and the Leizhou Peninsula areas.(2) From the prediction model, low suitability can be seen in the Changbai Mountains. But because this place nears to Korea and Japan, the higher-risk area, the molecular biology tests in laboratory were perphormed. Finally all of the experimental results were negative, this also proved that it’s still in the low or non-suitable areas.Conclusion:The MAXENT model which shows us visual image and evaluate species and disease risk areas scientifically. This research offered a gradient spatial distribution map to facilitate the spatial distribution prediction of disease risk.