The genus Henipavirus is a relatively new genus in the family Paramyxoviridae.¹  The best-known viruses in this genus are Hendra virus (HeV) and Nipah virus (NiV); the NiV species is further divided into the Malaysia (NiV-M) and Bangladesh (NiV-B) genotypes.²  HeV and NiV are categorized as WHO Risk group 4 Pathogens and can thus only be handled in biosafety level 4 (BSL4) laboratories.

In recent years, the Henipavirus genus was expanded with the discovery of the Cedar virus, Ghanaian bat virus and Mojiang virus species.^3–5  Pteropus spp. fruit bats are the natural reservoir of all henipaviruses except Mojiang virus that was so far only identified in rats (Rattus flavipectus).^3–7  Although henipaviruses were previously believed to be geographically limited to Southeast Asia and Australia, the identification of Ghanaian bat virus and subsequent serological surveys indicated that henipaviruses are likely present wherever their Pteropus spp. host is found.⁸  The more recently identified Henipavirus species Cedar virus, Ghanaian bat virus and Mojiang virus have not been isolated from humans and it is not clear if or how pathogenic they may be to humans. In contrast, HeV and NiV were discovered because of their link with severe disease in humans;^9,10  development of antivirals against henipaviruses has thus focused only on HeV and NiV. Therefore, the remainder of this chapter focuses on these two Henipavirus species only.