15 July 2008
Person confirmed with Hendra virusQueensland Health today confirmed that a Brisbane person has tested positive for Hendra virus, following an outbreak in horses last week.
The person was among a number tested for the virus after several horses contracted the disease at a Bayside veterinary hospital.
To date all other people who had been in close contact with the sick horses remain well. The following article contains information taken from various source explaining what Hendra Virus is and whether or not people living and working in the Ascot, Hendra and Clayfield areas need to be concerned..... Firstly we will start with some facts about the virus and then summarize what that means for our clients and others in the area.. What is the Virus Hendra Virus (HeV), previously known as equine morbillivirus (EMV), is a disease for which stringent biosecurity measures are necessary because it has the potential to be a serious zoonotic disease and there are important public health and workplace health and safety issue. HeV causes a broad range of clinical signs in horses. Hence many conditions could be regarded as `possible’ and require HeV exclusion. However, it is clear that HeV in the horse is a rare occurrence. It is known that close contact with HeV infected body fluids, particularly blood and thoracic fluid from a viraemic horse can cause infection in humans.
Where did it come from?
It appears that flying foxes are the natural reservoir for HeV. From the limited number of events to
date, transmission of HeV to aberrant hosts (horses, and in turn humans) largely overlaps the
birthing season of some species of flying foxes. The actual route of infection between flying foxes
and from flying foxes to horses is not yet known. Known sources of the virus are birthing fluids,
placental material and aborted pups. Other secretions from flying foxes such as saliva, urine and
faeces have not been shown to contain HeV to date. However the full cycle of infection in flying
foxes is not yet known and is being researched to produce a clearer picture. An association with late pregnancy and the birthing season of flying foxes is consistent with the
timing of five of the six HeV index cases recorded in horses – these cases having occurred
between August and January, which matches the late pregnancy and birthing season of three of the
four Australian flying fox species. However, the prevalence of infection in individual flying fox
populations may vary from year to year, and a reliable method for prediction of the high-risk period
within this time is not available. All HeV index horse cases have been recorded in horses that were paddocked in areas that were
attractive to flying foxes. Where companion horses were present in these paddocks, only on one
occasion was a companion horse infected. This animal was observed to lick the muzzle of its
recumbent companion at the time of death and died 12 days later. How can it be transmitted Experimentally, horses have not horizontally transmitted HeV infection to other horses. Cats and
guinea pigs have been shown to be experimentally susceptible to HeV infection and of these, cats
demonstrated an ability to transmit infection to horses in a transmission experiment. It is not known
whether cats can transmit infection to other animals or to humans. How long does it take to for a horse to get sick From information available, it can be said that the incubation period in horses (time from exposure
to first signs appearing) falls between 8 and 11 days. The course of illness for horses that die
averages a little over 2 days from first signs to death. Only seven horses of the 26 horses known to
have been infected survived the initial illness (a case fatality rate of over 70%). How Can I prevent myself getting sick? Please note the following information is for proffessionals who need to test and treat sick animals all other people must should avoid contact with suspected sick animals. See the summary below if you suspect you have a sick animal. Barrier protection in the form of gloves, respirator mask and face shield and impervious overalls
and boots should be worn by all persons treating, handling or performing necropsies on ‘possible’
or ‘probable’ HeV cases. All persons involved must be appropriately trained in the use of PPE and
must understand the risks present. Rigorous personal hygiene and hand washing is essential. Prevent contamination occurring, and if
it does, wash off contamination as soon as possible. In field situations where there may not be
ready access to hand washing amenities, ensure that alternative hand hygiene facilities (e.g. bucket
of water and soap) are available before handling the horse. Any cuts or abrasions that become
exposed or contaminated should be washed with soap and water and then be treated with either
iodine-based antiseptic or ethyl alcohol. For those who must work with possible cases. Personal Protective Equipment (PPE)
It is recommended that the following PPE be used:
• boots; and
• impervious overalls (long sleeves to prevent contamination of skin where there may be cuts and
abrasions) OR cotton or disposable overalls with impervious apron or impervious covering/coating;
and
• disposable impermeable gloves (e.g. latex or nitrile) double gloved; and
• face shield or safety eyewear (to protect against facial splashing); and
• particulate respirator. The minimum level of respiratory protection is provided by a disposable P2
particulate respirator.5 Such respirators should be available through your normal veterinary
supplier. All respirators should be fit checked prior to beginning work. How long does it remain in the environment? Virus remained viable at 22°C for more than four days in flying fox urine and for various times (mostly under
four days) in a range of fruit juices. At 37°C in both urine and juices, virus was inactivated in less than one
day, demonstrating a high susceptibility to increased temperatures. HeV was tolerant of a wide pH (acid's and alkali's) range (2-
11) but showed rapid inactivation following desiccation(drying). Our SummaryWhile Hendra virus has not been shown to be experimentally transmitted from horse to horse. It has certainly shown that it can move to cats and guinea pigs. This information together with the obvious transmission to people shown during outbreaks, means that it must be recommended to clients that suspect a horse to be unwell with signs that consist of:- - respiratory distress;
- frothy nasal discharge;
- elevated body temperature (above 40°C);
- elevated heart rate (increased to around 90 or 100 beats/minute
Should consider isolating the affected animal and immediately call in a veterinarian. The owner should notify the veterinarian of what they suspect and the veterinarian will follow protocols put in place by the Department of Primary Industries. Please also not that while horse to horse transmission has not been shown experimentally it seems to be a feature of many cases. All in contact horse should be isolated as well. In isolating the animal, children, ederley people, cats and all other animals should be kept away from the suspected horse, until it is cleared of infection. Concerns of people that, should they notify the DPI or there vet of a suspect horse, the response will be negative should not exist, procedures to test and clear animals are in place. Fatality rates in horses are high and will be even higher without veterinary intervention. Isolation also means anyone in contact with the animal should follow rigorous hygiene described above, and should they fell unwell immediately attend a local medical practitioner or hospital. Hendra virus can remain infectious on the surrounding equipment and facilities proper decontamination procedures need to be followed if a suspect case was moved from an area. Prevention of infection is best done by: - "These preventive measures in horses are based on extrapolations from the limited epidemiological
information available.
Stabling horses or moving them away from focal points of bat activity during the high risk months of August
to January should decrease the risk of exposure as all index cases to date have occurred in horses kept in
open paddocks where bat activity has been observed. (A horse brought in from an open paddock where
bats were active initiated the first observed outbreak in the stables.)
Placing horses in paddocks that do not contain trees attractive to bats for either feeding or roosting should
also decrease the risk of exposure. As well, horse feed bins or watering points should not be placed under
trees when there is a risk of bats coming in to that tree for feeding, resting or roosting.
3
As a precaution, remove dead flying fox pups and dead flying foxes from the horse area if found. This
should be done in a way that does not expose the handler to any fluids associated with the dead flying
foxes. Disposal can be undertaken by burial or burning." DPI Qld Much of the Information for this article was provide by the DPI QLd The following links provide a comprehensive source of info 
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