Hendra virus (Paramyxoviridae), that infects fruit bats or flying foxes (Pteropus
spp.), may occasionally to horses from which the infection pass on to humans.
Hendra virus causes acute, fatal, respiratory and/or neurologic disease in horses
of all ages. Clinical signs included fever, facial swelling, severe respiratory
distress, and terminally, copious frothy, blood-tinged nasal discharge. Ataxia
and myoclonus may also be seen. The predominant lesion in kidney, brain,
lymph nodes, spleen, liver, intestine, and lung is fibrinoid necrosis of vessels
with marked segmental to diffuse vasculitis and disruption of sub-endothelial
tunica intima. Syncytial endothelial cells containing viral antigen are common
in capillaries and arterioles. People and dogs have been infected as spillover
events from close contact with an infected living horse or with equine carcass
containing the virus. Fever, cough, sore throat, headache and tiredness are
common symptoms in human disease, also known as hantavirus pulmonary
syndrome (HPS). Meningitis and or encephalitis can also develop. Hendra virus
infection can be fatal. Diagnosis can be accomplished by viral isolation, PCR
or serology. There is no effective treatment for clinically infected individuals.
A commercial vaccine licensed in Australia for horses (Equivac® HeV) prevents
clinical disease in horses and could be beneficial for other animal species and
eventually also for humans.