Ebola virus (EBOV) is highly pathogenic, with a predisposition to cause 
outbreaks in human populations accompanied by significant mortality. An ovine 
polyclonal antibody therapy has been developed against EBOV, named EBOTAb. When 
tested in the stringent guinea pig model of EBOV disease, EBOTAb has been shown 
to confer protection at levels of 83.3%, 50% and 33.3% when treatment was first 
started on days 3, 4 and 5 post-challenge, respectively. These timepoints of 
when EBOTAb treatment was initiated correspond to when levels of EBOV are 
detectable in the circulation and thus mimic when treatment would likely be 
initiated in human infection. The effects of EBOTAb were compared with those of 
a monoclonal antibody cocktail, ZMapp, when delivered on day 3 post-challenge. 
Results showed ZMapp to confer complete protection against lethal EBOV challenge 
in the guinea pig model at this timepoint. The data reported demonstrate that 
EBOTAb is an effective treatment against EBOV disease, even when delivered late 
after infection.