Plants, arthropods, rodents, and birds have also been considered possible viral reservoirs.Bats were known to roost in the cotton factory in which the first cases of the 1976 and 1979 outbreaks were observed, and they have also been implicated in Marburg virus infections in 1975 and 1980. Of 24 plant and 19 vertebrate species experimentally inoculated with EBOV, only bats became infected. The bats displayed no clinical signs of disease, which is considered evidence that these bats are a reservoir species of EBOV. In a 2002–2003 survey of 1,030 animals including 679 bats from Gabon and the Republic of the Congo, immunoglobulin G (IgG) immune defense molecules indicative of Ebola infection were found in three bat species; at various periods of study, between 2.2 and 22.6% of bats were found to contain both RNA sequences and IgG molecules indicating Ebola infection. Antibodies against Zaire and Reston viruses have been found in fruit bats in Bangladesh, suggesting that these bats are also potential hosts of the virus and that the filoviruses are present in Asia.Between 1976 and 1998, in 30,000 mammals, birds, reptiles, amphibians and arthropods sampled from regions of EBOV outbreaks, no Ebola virus was detected apart from some genetic traces found in six rodents (belonging to the species Mus setulosus and Praomys) and one shrew (Sylvisorex ollula) collected from the Central African Republic. However, further research efforts have not confirmed rodents as a reservoir.
It is recommended that survivors of EVD wear condoms for at least twelve months after initial infection or until the semen of a male survivor tests negative for Ebola virus on two separate occasions.Survivors develop antibodies against Ebola that last at least 10 years, but it is unclear whether they are immune to additional infections. Cause
EVD in humans is caused by four of six 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 and sixth viruses, Reston virus (RESTV) and Bombali virus (BOMV), are not thought to cause disease in humans, but have caused disease in other primates. All five viruses are closely related to marburgviruses. Virology
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 shepherds crook, of a "U" or of a "6," and they may be coiled, toroid or branched.