<P> Those who survive often have ongoing muscular and joint pain, liver inflammation, decreased hearing, and may have continued tiredness, continued weakness, decreased appetite, and difficulty returning to pre-illness weight . Problems with vision may develop . </P> <P> Survivors develop antibodies against Ebola that last at least 10 years, but it is unclear whether they are immune to additional infections . </P> <P> EVD in humans is caused by four of five viruses of the genus Ebolavirus . The four are Bundibugyo virus (BDBV), Sudan virus (SUDV), Taï Forest virus (TAFV) and one simply called Ebola virus (EBOV, formerly Zaire Ebola virus). EBOV, species Zaire ebolavirus, is the most dangerous of the known EVD - causing viruses, and is responsible for the largest number of outbreaks . The fifth virus, Reston virus (RESTV), is not thought to cause disease in humans, but has caused disease in other primates . All five viruses are closely related to marburgviruses . </P> <P> Ebolaviruses contain single - stranded, non-infectious RNA genomes . Ebolavirus genomes contain seven genes including 3' - UTR - NP - VP35 - VP40 - GP - VP30 - VP24 - L - 5' - UTR . The genomes of the five different ebolaviruses (BDBV, EBOV, RESTV, SUDV and TAFV) differ in sequence and the number and location of gene overlaps . As with all filoviruses, ebolavirus virions are filamentous particles that may appear in the shape of a shepherd's crook, of a "U" or of a "6," and they may be coiled, toroid or branched . In general, ebolavirions are 80 nanometers (nm) in width and may be as long as 14,000 nm . </P>

Where is the ebola virus found in the body