Hendra Virus Infection in Horses: A Review on Emerging Mystery Paramyxovirus

Hendra virus (HeV) is a zoonotic paramyxovirus which causes acute and deadly infection in horses (Equus caballus). It is a rare and unmanaged emerging viral infection in horses which is harbored by bats of the genus Pteropus (Australian flying foxes or fruit bats). The virus is pleomorphic in shape and its genome contains nonsegmented negative-stranded RNA with 18234 nucleotides in length. The virus is transmitted from flying foxes to horses, horse to horse, and horse to humans. Human-to-human transmission of HeV infection is not reported yet. The infection of HeV in horses is highly variable and shows broad range of signs and lesions including distinct respiratory and neurological disorders. Currently, there are no specific antiviral drugs available for the treatment of HeV infection in horses. Vaccination is considered as prime option to prevent HeV infection in horses. A subunit vaccine, called as "Equivac HeV vaccine" has been approved recently for preventing this viral infection in horses. In addition, a plethora of common preventive strategies could help restrict the inter- and intra-species transmission of HeV. Considering the scanty but severe fatality cases of this mystery virus as well as lack of proper attention by veterinary scientists, this review article spotlights not only on the clinical signs, transmission, epidemiology, biology, pathogenesis, and diagnosis of HeV but also the preventive managements of this uncommon infection in horses by vaccination and other precautious strategies.