Pathogenicity between species of Ebola does not differ greatly in that they have all been associated with hemorrhagic fever outbreaks in humans (excluding Reston) and non-human primates. The Ebola-Zaire and Sudan strains are especially known for their virulence with up to 90% fatality rate , with reduced virulence noted in the Tai Forest ebolavirus and the more recently discovered Bundibugyo strain, which caused a single outbreak in Uganda . Bundibugyo was the outbreak virus in Isiro, Democratic Republic of Congo, in 2012....
The largest recorded ebolavirus outbreak to date began in March 2014, with initial cases reported in Guinea and then additional cases identified in the surrounding regions (Liberia, Sierra Leone, Nigeria). A new strain of the ZEBOV species was identified as the causative agent of the outbreak ...
Bats are considered to be a plausible reservoir for the virus. Serological evidence of infection with ebolavirus (antibody detection to EBOV, ZEBOV, and/or REBOV) has been reported in fruit bats collected from woodland and forested areas near Ghana and Gabon, with reduced frequency of isolation from bats collected in mainland China and Bangladesh .
INFECTIOUS DOSE: Viral hemorrhagic fevers have an infectious dose of 1 - 10 organisms by aerosol in non-human primates...
In an outbreak, it is hypothesized that the first patient becomes infected as a result of contact with an infected animal. Person-to-person transmission occurs via close personal contact with an infected individual or their body fluids during the late stages of infection or after death...
Nosocomial infections can occur through contact with infected body fluids for example due to the reuse of unsterilized syringes, needles, or other medical equipment contaminated with these fluids ......
In laboratory settings, non-human primates exposed to aerosolized ebolavirus from pigs have become infected, however, airborne transmission has not been demonstrated between non-human primates...
INCUBATION PERIOD: Two to 21 days .
COMMUNICABILITY: Communicable as long as blood, body fluids or organs, contain the virus. Ebolavirus has been isolated from semen 61 to 82 days after the onset of illness, and transmission through semen has occurred 7 weeks after clinical recovery ...
SURVIVAL OUTSIDE HOST: Filoviruses have been reported capable to survive for weeks in blood and can also survive on contaminated surfaces, particularly at low temperatures (4°C)....When dried in tissue culture media onto glass and stored at 4 °C, Zaire ebolavirus survived for over 50 days ...
A study on transmission of ebolavirus from fomites in an isolation ward concludes that the risk of transmission is low when recommended infection control guidelines for viral hemorrhagic fevers are followed Footnote 64. Infection control protocols included decontamination of floors with 0.5% bleach daily and decontamination of visibly contaminated surfaces with 0.05% bleach as necessary...