Ebola is a zoonotic virus,primarily transmitted through direct contact with the bodily fluids of infected individuals,such as blood,sweat,vomit,feces,urine,saliva,or semen.There is currently no evidence of airborne transmission via droplets.Despite extensive research by the World Health Organization,no animal host capable of surviving an outbreak has been identified to date;fruit bats are currently considered a possible natural reservoir.Due to the high fatality rate of Ebola and the fact that no vaccine has yet been proven effective,the virus is classified as a Biosafety Level 4 pathogen and is also regarded as a potential tool for bioterrorism.

　　Electron microscopy studies of members of the Ebola virus genus reveal a filamentous structure typical of filoviruses.Viral particles may also appear in“U”shapes,“6”shapes,coiled,circular,or branched forms;however,laboratory purification techniques—such as high-speed centrifugation—may contribute to the formation of these shapes by deforming the virus particles.Viral particles are typically about 80 nanometers in diameter but can reach up to 1,400 nanometers in length,with the average length of a typical Ebola virus particle being close to 1,000 nanometers.At the center of the viral particle,the nucleocapsid is composed of the helical genomic RNA along with nucleoproteins and the viral proteins VP35,VP30,and L.The viral glycoprotein extends 10 nanometers from the surface into the viral particle,with another 10 nanometers protruding outward from the envelope.This envelope is derived from the host cell membrane.The region between the envelope and the nucleocapsid,known as the matrix space,is composed of the viral proteins VP40 and VP24.