Biosecurity Queensland is managing a new Hendra virus case near Mackay after a positive test result was received on 22 January 2013 after one horse had died on the property after becoming unwell.
Source of Hendra virus
Biosecurity Queensland has quarantined a property where one horse has died from Hendra virus and another is unwell and are working to determine what contact the infected horse had with other animals.
© 2013 by Justin Welbergen
Biosecurity Queensland is in the process of quarantining the property. There are other horses on the property and we will be working to determine what contact the infected horse had with other animals.
Testing and monitoring will then be undertaken over the next month. While under quarantine, restrictions will apply to moving horses and horse materials on and off the infected property.
The Queensland Government advises that a Hendra virus vaccine for horses produced by commercial manufacturer was released on 1 November 2012.
This vaccine has been released under special conditions and only veterinarians who have completed an online training module managed by the manufacturer will be accredited to administer the vaccine.
The Equivac HeV Hendra virus vaccine for horses is a vaccine, which aids in the prevention of Hendra virus infection in horses from four months of age. Equivac HeV is a ‘subunit’ vaccine, meaning it contains only a small part of the Hendra virus; a protein from the virus surface. The product is being sold under permit issued by the Australian Pesticides and Veterinary Medicines Authority (APVMA)
How does the Equivac HeV Hendra virus vaccine for horses work?
The vaccine stimulates the production of protective antibodies. If the horse is subsequently exposed to Hendra virus, the antibodies will bind the viral particles preventing them from establishing an active infection in the horse. The viral particles bound to the antibody are then further processed by the immune system and eliminated.
How is the vaccine administered?
Only approved veterinarians can administer the vaccine by injection into the muscles on the side of the neck. Two 1mL doses are given at an interval of three weeks, and antibodies are generated within three weeks of the second vaccine dose being given.
How effective is the vaccine?
Initial trials have shown complete protection when vaccinated horses were exposed to an otherwise lethal dose of the Hendra virus.
Can the Equivac HeV cause the Hendra virus?
No, the vaccine is not live and cannot cause infection in horses. Live virus is not used at any stage in manufacturing this vaccine.
Since its first appearance in 1994, the Hendra virus has killed more than 80 horses and four of the seven people infected to date. An equine vaccine is crucial to breaking the cycle of Hendra virus transmission from flying foxes to horses and then to people, as it helps to prevent the horse from both developing the disease and transmitting the virus to other horses and people.
Experiments have shown that vaccinated horses survived infection by Hendra virus and have shown no evidence of virus, disease, replication or shedding of the virus, a critical finding to help prevent transmission.
The vaccine is derived from original work by Broder and Katharine Bossart, Ph.D., a USU alumna and assistant professor at Boston University School of Medicine. Their work was supported by the National Institute of Allergy and Infectious Disease (NIAID), part of the National Institutes of Health.
To date, Hendra virus has been found only in Australia. The nation experienced an unprecedented number of 18 outbreaks across Queensland and New South Wales in 2011, during which 22 horses died or were euthanized. Authorities detected the first case of Hendra virus antibodies in a dog within a natural environment that same year.
The virus has appeared seven times in 2012, causing equine deaths and serious cases of human exposure to infection. In July 2012, a woman with significant exposure risk was given an experimental human monoclonal antibody therapy on a compassionate use basis. Dimitar Dimitrov, Ph.D., of the NIH, working in collaboration with Broder, developed the antibody, known as m102.4.
The recent work to develop and evaluate the Hendra vaccine was jointly funded by CSIRO; Pfizer Animal Health; the Australian government through its Department of Agriculture, Fisheries and Forestry; and the Queensland government through its Department of Employment, Economic Development and Innovation. NIAID provided funding to support production of the vaccine component in the U.S.
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