HENDRA VIRUS FACT SHEET FROM LEADING VETERINARY SURGEON..DR. DAVID LOVELL.SCROLL ON DOWN F0R STEPS TO "HENDRA PROOF" YOUR HORSE AND YOURSELF..07/07/2011..
HENDRA VIRUS – THE FACTS
Hendra is back with a vengeance. The fact of the matter is that it has never gone away. The disease is here, is a fact of life, and the reality is that we all have to learn to live with it. Commonsense, understanding the disease, and some basic management steps will ensure that we can all still enjoy our equestrian activities with a minimum of risk. Even better news is the remarkable progress scientists are making with the development of a vaccine which will, if universally taken up, be the answer to the problem. It looks like there is a very reasonable chance that we will have vaccine available next year. The current situation is calamitous with 4 separate outbreaks to date and the possibility of more to happen. The period May through September is regarded as the “peak period” for Hendra although it has happened throughout the year, but it appears that June, July and August have been predominant. Of some real concern is the statement by the chief veterinary officer that sampling this year has reported a 30% incidence of virus in bat samples as compared to some 10% in other years.
Basically the disease is present in fruit bats without having any apparent clinical effect on them. It is known that the virus can be shed at particular times in the fluid secretions of the bat, with saliva and urine being potent sources. A relevant fact about fruit bats is that they ingest fruit and nectar, process it in their fore stomach, and then regurgitate it or “spit” it out in what are known as spats. This material has a high concentration of saliva and potentially, could be palatable to horses as in reality it is simply processed fruit material. One of the very pertinent findings reported by Dr Hume Fields, Our own leading Queensland world authority on fruit bats, is that they have been able to find very high concentrations of virus material directly under trees in what they call the “drip zone” and almost no virus once they leave the perimeter of the trees. This area is where the spats and urine of feeding bats will be dropped and potentially an extremely high risk area for horses. These findings are not yet published but I believe that they are critical information that horse owners need to understand as it provides solid proof that there is a very real “hot zone” of opportunity for horses to become infected. The obvious outcome is that management of horses must absolutely prevent horses from access to these areas.
For a horse to contract Hendra virus, they must have direct access to a source of the virus. They will not catch Hendra virus from “the wind”. Direct access to a source of the virus means either fruit bat fluids or another infected horse that is actually excreting virus. Humans then need to be exposed to fluids from a horse excreting the virus. (Nothing has ever been proven that a human could not contract the disease directly from exposure to bat fluids so always keep that in mind). A disturbing fact is that it is now known that a horse can actually secrete the virus for a short period of time before actually displaying any clinical abnormalities. (It is critical to remember that there is an incubation period of 5 – 16 days from when the horse is exposed to the virus and when it will develop signs of disease). An understanding of these simple facts regarding Hendra virus provide us with the keys to management that will allow us to eliminate, or certainly dramatically reduce, the risks from this disease.