HENDRA VIRUS INFECTION AWARENESS

Aug 02, 2011

 

Whilst we have not had a positive Hendra Virus infected horse in Victoria
with the recent cases in Queensland and northern NSW we must be aware of the risks surrounding Hendra virus and the need for preventative measures to minimise the risk of horse and human infection.

The natural hosts of Hendra virus are bats (flying foxes) which can then pass the virus onto horses. Human infection results from close contact with the blood, body fluids and tissues of infected horses. There is no evidence of human‐tohuman or bat‐to‐human spread of Hendra virus.

It is known from previous outbreaks that first contact with the virus usually occurs in the paddock, when a horse is grazing under a tree inhabited by flying foxes, comes in contact with the virus‐laden flying fox excreta and other bodily fluid aerosols. The infected horse can then pass the infection on to other horses that are in close proximity, such as in a stable environment. Horses returning to a racing stable from a spelling
property therefore pose a relatively greater risk of transmitting infection than horses already in the stable.

 

Hendra virus infection of horses can include;

Clinical Signs
• acute onset of illness
• increased body temperature
• increased heart rate• discomfort/ weight shifting between legs
• depression
• rapid deterioration

Respiratory signs
• pulmonary oedema and congestion
• respiratory distress — increased respiratory rates
• terminal nasal discharge — can be initially clear, watery discharge progressing to
stable white froth and/or stable blood‐stained froth

Neurological signs
• ‘wobbly gait’ progressing to loss of control of muscle movement
• altered consciousness — apparent loss of vision in one or both eyes, aimless walking in
a dazed state
• head tilting, circling
• muscle twitching
• urinary incontinence
• lying down with inability to get up
• terminal weakness, loss of control of muscle movement and collapse

 

Protection of horses


The risk of Hendra virus infection in horses is higher in situations where horses are kept outdoors in areas where flying foxes are known to inhabit. Flying foxes often visit properties where native eucalypts, bottlebrushes, lilli‐pillies, figs and melaleucas are flowering. Blossoms are their primary source of food. They will also feed on palm seeds and exotic fruits when native food is less abundant.


Horse owners/trainers should follow these steps to protect their horses:


• Place feed and water containers under cover if possible
• Do not place feed and water containers under trees, particularly if flying foxes are
attracted to those trees.
• Do not use feed that might be attractive to flying foxes if they are known to be in the
area. Fruit and vegetables (e.g. apples, carrots) or anything sweet (e.g. molasses) may
attract flying foxes.
• If possible, remove horses from paddocks where flowering or fruiting trees have resulted in a temporary surge in flying fox numbers. Return the horses after the trees have stopped flowering or fruiting.
• If removal of horses from paddocks is not possible, restrict their access to the areas where the flying foxes are active and for the period of time they are present (e.g., by fencing off trees where the animals roost or where they gather while flowers and fruit are present).
• Maintain a high level of routine stable hygiene, including covering any cuts or abrasions on exposed skin before handling horses and washing hands well with soap and water, especially after handling your horse's mouth or nose (eg fitting or removing a bridle) and before eating, smoking or touching your eyes, nose or mouth.

Protection of humans

The risk of human infection can be greatly reduced by adopting good hygiene practices as a matter of routine, by washing your hands with soap and water regularly before, during and after handling horses.

 

For further information on Hendra Virus please refer to the Department of Primary Industries website.

http://new.dpi.vic.gov.au/agriculture/pests‐diseases‐and‐weeds/animaldiseases/horses/hendra‐virus

To report suspicions of Hendra virus infection, contact your local vet or the Department of Primary Industries on 136 186.