Hendra virus infection

Hendra virus infection is a rare emerging zoonosis caused by Hendra henipavirus (Henipavirus hendraense), a member of the genus Henipavirus in the family Paramyxoviridae ^[2]. The natural host has been identified as fruit bats of the genus Pteropus, commonly known as flying foxes, in which the virus is endemic with a seroprevalence of approximately 47% ^[2]. Horses serve as intermediate hosts and dead-end hosts, while humans become infected through close contact with infected horses ^[1][3].

Symptoms of Hendra virus infection in humans range from mild influenza-like illness to fatal respiratory or neurological disease, including hemorrhage and edema of the lungs and in some cases viral meningitis ^[1][2]. In horses, infection usually causes pulmonary oedema, congestion, and neurological signs ^[2]. Flying foxes experimentally infected with Hendra virus develop viraemia and shed the virus in urine, faeces, and saliva for approximately one week without showing signs of illness ^[2].

As of July 2016, 53 disease incidents involving over 70 horses have been reported, all confined to the north-eastern coast of Australia ^[1]. A total of seven humans have contracted Hendra virus from infected horses ^[1][2]. Hendra virus infection of horses occurred sporadically between 1994 and 2010, with an unprecedented number of outbreaks recorded in 2011 ^[3]. Since 1994, Hendra virus has caused the death of over 100 horses ^[2]. In 2021, a new variant named "Hendra virus genotype 2" (HeV-g2) was identified in two flying fox species in Australia, sharing 84% sequence homology with other published Hendra virus genomes ^[2].

Flying foxes (Pteropus species) are the reservoir host of Hendra virus ^[2]. Horses become infected after exposure to bodily fluids from infected flying foxes, typically through urine, faeces, or masticated fruit covered in flying fox saliva when horses graze below roosting sites ^[2]. Humans contract infection primarily through close contact with infected horses, particularly during care or necropsy of ill or dead horses ^[1]. Direct transmission from infected horses to other horses has also been documented ^[2].

A registered inactivated subunit vaccine for horses against Hendra virus is available and is recognized as an effective way to reduce the risk of horses becoming infected and to reduce the likelihood of human exposure ^[1][3]. Through preventing the development of acute Hendra virus disease in horses, vaccine use is expected to reduce the risk of transmission of infection to people ^[3]. There is no specific treatment for human cases; intensive supportive care is provided, and the use of monoclonal antibodies is being investigated ^[1].

1. 1World Health Organization. Hendra virus infection [Internet]. cited 4 Sept 2026.Available from: https://www.who.int/health-topics/hendra-virus-infection
2. 2Wikipedia contributors. Hendra virus - Wikipedia [Internet]. Wikipedia. cited 4 Sept 2026.Available from: https://en.wikipedia.org/wiki/Hendra_virus
3. 3Middleton D et al. Hendra virus. Vet Clin North Am Equine Pract. 2014 Dec. PMID: 25281398. doi: 10.1016/j.cveq.2014.08.004.PubMed: https://pubmed.ncbi.nlm.nih.gov/25281398/