Filoviruses are known to cause severe hemorrhagic fever in human and non-human primates, but recent studies suggest that quadrupeds are also naturally susceptible to EBOV infection (Figure 1, right) . In 2008-2009, REBOV infection was confirmed for the first time in pigs in the Philippines (Barrette et al., 2009) . REBOV was occasionally isolated from the samples subjected to the diagnostic investigation of multiple outbreaks of a respiratory and abortion disease syndrome in swine, which were caused by porcine reproductive and respiratory syndrome virus, common in pigs in Asia. It is speculated that REBOV became detectable, most likely due to the coinfection with this porcine virus. Although pathogenicity of these swine REBOV strains to humans, non-human primates, or even pigs remains unclear, other EBOV species (i.e., ZEBOV) was shown to cause severe respiratory disease in experimentally infected pigs (Kobinger et al., 2011) . During the 2001-2003 ZEBOV outbreaks in Gabon and the Democratic Republic of the Congo (DRC), when large numbers of FIGURE 1 | Phylogenetic analysis of filovirus GP amino acid sequences. The phylogenetic tree was constructed using the neighbor-joining method. For construction of this tree, ten complete GP amino acid sequences were used. Infectious viruses were isolated or viral genome and/or specific antibodies were detected (in parentheses) from the animals shown on the right.