Introduction
Hendra virus or the Hendra henipavirus belongs to the Paramyxoviridae family of viruses and is related to the Nipah virus. Both are considered to be different species of the genus Hepina. It got its name due to the respiratory outbreak among horses and humans caused by the virus in Hendra, Australia, in 1994. Bats (flying foxes) are considered to be the reservoir or storehouse of viruses.
What Is Hendra Virus Infection?
Hendra virus infection (HeV) is a zoonosis infection. Zoonosis is an infection that is transmitted from an animal to humans. HeV infection is a bat-borne infection.
How Common is HeV Infection?
Till 2013 the infections arising due to the said virus remain a rare phenomenon worldwide. Hev infections show a seasonal pattern. The outbreak of Hev is found to be more between May and October.
Does the HeV Infection Follow Any Specific Geographic Distribution?
The outbreak of the infections caused by the Hendra virus follows a specific geographic outbreak. However, Hendra and Nipah virus both belong to the same family. The Nipah virus infections are more widely distributed worldwide, such as in Malaysia, India, and Thailand. However, the infections of the Hendra virus are more localized to the Australian belt, Okinawa, and south-east Asia.
How Is the Virus Transmitted?
p>The transmission of the virus occurs by the transfer of the virus from the body fluids like the excreta, urine, etc., of the horse or fruit bats belonging to the Pteropodidae family and genus Pteropus (flying foxes). Therefore, people having close contact with infected horses are more prone to contracting the virus. However, no human-to-human transfer of the virus has been reported.
How Does the Virus Spread From Animals to Humans?
The virus is present inside the bat's bloodstream (viremia) for almost a week and sheds the virus in the environment through their body excretion. Humans and horses in close contact with the excretions acquire the virus.
Who Is More Prone to Getting the Hendra Virus?
The primary reservoir of the virus remains the flying fox bats and the horse. Hence, people closely associated with these animals for occupational or recreational purposes are at an increased risk of getting infected with the virus.
Where Is the Virus Found in Abundance Inside the Human Body?
The virus is present inside and can be recovered from various regions, such as the lungs, kidneys, spinal cord, upper respiratory tract, heart, and adrenal glands.
What Are the Signs and Symptoms of Hendra Virus Infections?
Hendra virus mainly causes infections that affect the respiratory system. Therefore, people experience
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Hemorrhage and edema of the lungs.
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Inflammation of the meninges (viral meningitis).
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Patients may also suffer from neurological symptoms.
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Enlarged and edematous submandibular, bronchial, and sternal lymph nodes.
How Is the Hendra Virus Detected?
The diagnosis of patients suffering from Hendra virus infection takes place in a highly isolated environment to avoid contamination. The virus diagnosis is made when the patients are in the acute phase or recovering (convalescent) stage of the infection. The following methods detect the virus:
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Enzyme-linked immunosorbent assay (ELISA) is performed to detect the IgG and IgM antibodies formed inside the host's body against the virus.
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Real-time polymerase chain reaction (RT-PCR) also helps identify the viral genetic material.
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Laboratory investigations for RT-PCR and antibody detection are done by collecting the patient's serum, nasal and throat swabs, and cerebrospinal fluid.
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Stall-side tests using antibody-conjugated magnetic particles and quantum dots show promising results in detecting the virus.
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Virus isolation.
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Histopathological examination of the infected tissue with immunofluorescence staining.
How Is Hendra Infection Managed?
There is no specific cure for the infection. Therefore, the current treatment mainly aims to provide symptomatic relief and intensive care therapy. Ribavirin, an antiviral drug, is effective against the virus.
What Are the Complications Associated With the Hendra Virus?
Hendra virus infections can, in severe cases, lead to death. The other complication of the virus is encephalitis (inflammation of the brain region).
What Are the Conditions That Are Similar to the HeV?
The conditions or infections that are to be ruled out before forming a confirmatory diagnosis of HeV are:
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Acute African horse sickness.
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Virulent equine influenza.
What to Do if a Person Gets Exposed to the Virus?
If a person gets infected with HeV, animal vaccines have been developed by the national institute for infectious and allergic diseases (NIAID). The vaccine works by neutralizing the antigens of the virus. Monoclonal antibody therapy is also found to be effective in neutralizing the virus in patients post-exposure to the virus.
How to Prevent Hendra Infection?
The infection caused by the virus can primarily be prevented by reducing exposure to the sources of the virus.
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People should avoid contact with horses infected with the Hendra virus infection.
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People who are in charge of the care of the infected virus should do so by wearing personal protective equipment (PPE).
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Avoid nuzzling or kissing the horse if it is sick.
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Cover cuts or abrasions on the skin before touching the horses.
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Wash the hands properly before and after handling the horses.
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Only a few people should take care of horses suspected of HeV infection.
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Healthcare workers and veterinarians should always equip themselves with (PPE) while managing the animals.
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Till now, the commercial vaccine for Hendra is available for horses only.
Is Hendra’s Infection Serious?
Infections caused by the Hendra virus are rare, but the fatality rate of the diseases caused by the virus is high, with more than 57 % mortality rate.
Conclusion
Hendra virus belongs to the Paramyxoviridae family and is closely related to the Nipah virus. It is primarily present in fruit bats and can be acquired by equines through direct contact with the bat's bodily secretions. It is transmitted to humans by horses or by bats themselves. HeV infected patients show flu-like and neurological symptoms. The diagnosis of the virus is similar to that of the Nipah virus (RT-PCR and ELISA). There is no particular treatment for the infection caused by the virus. However, commercial vaccines are available for horses. Such vaccines for the prevention of infection in humans are under trial.
