Hendra Virus Disease: Transmission, Signs, Symptoms, Treatment, Prevention

Hendra virus is a member of the family paramyxoviridae with the natural reservoir being the flying foxes.

Hendra virus disease is rare in humans. The first outbreak of Hendra virus was recorded in the Brisbane suburb of Hendra, Australia, in 1994.⁽¹⁾ This outbreak involved only two human cases and 21 stabled racehorses.

Hendra virus can be transmitted to humans if they come in contact with the body fluids and excretions of horses infected with Hendra virus. The horses get infected on coming in contact with the urine of infected flying foxes. It happens when the horses come in contact with the fruits, urine, or feces covered in flying fox saliva while grazing.

To date, no human to human transmission of Hendra virus has been recorded.⁽²⁾ Veterinarians are more at risk of contracting the Hendra virus.

People who have close contact with horses, especially the infected horses are more at risk of getting infected with the virus. It can also occur more in those who do not use appropriate protective equipment while handling horses.

The incubation period of the Hendra virus is 9-16 days. The symptoms shown by someone infected with the virus are respiratory illness or severe flu-like signs and symptoms.

Hendra virus symptoms in horses are:

• Rapid onset of illness
• Fever
• Increase in heart rate
• The rapid deterioration of respiratory and neurological signs

Hendra virus symptoms in human are:

• The symptoms start appearing in 5-21 days of infection with the virus or after coming in contact with the infectious horse
• Fever, cough, sore throat, headache, and tiredness
• Meningitis or encephalitis can develop causing headache, high fever, drowsiness, and sometimes convulsions and coma
• It can be fatal in some humans.
• In spite of being a rare illness, the fatality rate of infection caused by Hendra virus is 57%.⁽³⁾

The laboratory tests that can help diagnose the Hendra virus are:

• Detection of antibody (IgG and IgM) by ELISA. This test is done to detect the antibodies in the serum or the cerebrospinal fluid
• Real-time polymerase chain reaction (RT-PCR) is done on the serum, cerebrospinal fluid, and the throat swab.
• Virus isolation from the cerebrospinal fluid or throat swabs
• The test for Hendra virus need to be done in high containment laboratories

A drug named ribavirin has been found to be effective against the Hendra virus in vitro, but there is no clinical evidence to prove the same. There is no specific treatment for humans suffering from Hendra virus infection. Intensive supportive care can be helpful and the use of monoclonal antibodies is being investigated.

Detection of the disease in the intermediate animal host is the crucial means of limiting its spread to humans. The occurrence of the Hendra Virus in humans is associated with infection of the intermediates sources such as horses.

The Hendra Virus disease can be prevented by avoiding coming in contact with the infected horses.

There is a registered Hendra animal vaccine and is a recognized effective way to reduce the risk of horses becoming infected that would reduce the likelihood of human exposure as well. No human vaccine is available.

The following measures can help prevent human infection of Hendra virus:

• The infected horse can shed the virus even before showing the signs of illness. It is therefore important to maintain hygiene when around horses.
• Never kiss the horse on the muzzle
• If there is any cut or skin exposure, make sure you cover it before handling horses. Wash hands with soap and water after handling the horse mouth or nose.
• If infected with Hendra virus, do not donate blood or tissue unless you are cleared off the infection.
• Use appropriate personal protective equipment when the contact is necessary.