Hendra Virus Infection

Hendra virus is a highly infectious zoonotic pathogen that poses a significant threat to horses and humans. Since its initial identification in Australia in 1994, this virus has been associated with multiple outbreaks, generating concerns within the veterinary and public health sectors. BioVenic is committed to helping customers improve or develop diagnostic, treatment, and prevention solutions for the virus to mitigate its impact on public health.

Etiology and Epidemiology

Hendra virus has the largest genome in the family Paramyxoviridae, genus Henipavirus. Hendra virus is closely related to another zoonotic pathogen known as the Nipah virus. Fruit bats, particularly flying foxes, serve as the natural reservoir hosts of the virus. Horses are considered intermediate hosts, with occasional spillover infections occurring in dogs and humans.

Fig. 1 Schematic diagram of the structure of Hendra virus particle.¹

Both the discovery and the outbreak of the virus occurred in Australia, and it caused human deaths. To this day, the geographic distribution of Hendra virus infection remains largely restricted to Australia, mainly the northeastern states with rich flying fox populations.

Pathogenesis

Following transmission to a susceptible host, the Hendra virus initially targets the respiratory epithelium. The virus's ability to rapidly replicate in respiratory tissues leads to systemic dissemination, affecting various organs, including the lungs, liver, spleen, and brain. The immune response plays a crucial role in the pathogenesis of the disease, with excessive inflammation contributing to tissue damage and organ dysfunction. In light of this, Hendra virus-infected horses exhibited pronounced respiratory symptoms.

Transmission

Current transmission routes may include the following,

• Horses can become infected with the virus through contact with or consumption of water or food contaminated by flying foxes carrying the Hendra virus.
• Horses and humans are primarily infected through direct contact with respiratory secretions, blood, and tissues of infected horses.
• Hendra virus has not been proven to be transmitted to humans and dogs by flying foxes, nor can it be transmitted from person to person.

Fig. 2 Transmission cycle diagram of Hendra virus.²

Public Health Risk

Hendra virus infection represents a significant zoonotic risk due to its ability to infect humans and cause severe illness. The close interaction between horses and humans in equestrian activities, veterinary care, and horse husbandry increases the likelihood of exposure. Human infections are rare but can lead to severe respiratory and neurological symptoms, necessitating prompt medical attention.

Signs and Symptoms

Infected horses manifest a range of clinical signs, often including,

The severity of the disease can vary, with some horses experiencing rapid deterioration, necessitating euthanasia.

Symptoms of Hendra virus in humans usually appear 5 to 21 days after contact with an infected horse and manifest as,

Diagnosis

BioVenic provides customers with one-stop diagnostics solutions, including methods, reagents, and kits, capable of detecting antigens or antibodies of the Hendra virus on samples such as blood, urine, nasal swabs, tissue samples, and cerebrospinal fluid.

Treatment

For humans or horses infected with Hendra virus, there is no specific antiviral treatment available.

• Infected horses whose condition deteriorates rapidly require euthanasia.
• Horses with mild disease may be treated supportively to relieve symptoms.
• Humans with suspected infections should be hospitalized immediately for treatment.

Prevention and Control

• Ensure that horses do not come into contact with flying foxes.
• Avoid contamination of water and feed with body fluids or urine of flying foxes.
• Horses can be vaccinated in endemic areas.
• When an infected horse is suspected, avoid direct contact with body fluids or secretions of sick animals and report them immediately.
• Avoid contact with Hendra virus-infected livestock, such as horses, and personal protective equipment must be used.
• Good hygienic habits should be developed, do not kiss the muzzle of the horse, wash hands, and disinfect immediately after touching the horse.

Hendra virus infection poses a significant threat to horses and humans. BioVenic is committed to advancing our understanding of Hendra virus infection and developing innovative solutions. Our scientists assist veterinary researchers in driving advances in diagnostics, treatments, and preventive measures. Contact us now for more information.

References

1. Khusro, Ameer, et al. "Hendra virus infection in horses: A review on emerging mystery paramyxovirus." Journal of Equine Veterinary Science 91 (2020): 103149.
2. Mendez, Diana Hélène. "Identifying and understanding the factors affecting infection control and Hendra virus risk management in private veterinary practices in Queensland, Australia." PhD diss., James Cook University, 2015.