Before making direct contact with a patient, an attending veterinarian should assess factors that may contribute to Hendra virus (HeV) spill-over and put steps in place to manage work health and safety obligations and human health risks.

Consider the possible combination of risk factors below when you decide on the risk management measures and actions you will take while dealing with equine patients, including providing sound advice to clients.

Always take the following into account:

• Consider standard work health and safety responsibilities and appropriate risk management strategies when dealing with sick horses. More information on this can be found in the Australian Veterinary Association's Guidelines for veterinary personal biosecurity and Workplace Health and Safety Queensland's information on work health and safety and diseases from animals.
• Horses have shown variable, and sometimes vague, clinical signs, particularly in the early phase of HeV infection. You should therefore conduct an assessment before you have direct contact with equine patients. Your risk assessment may evolve while attending the case as more information comes to hand.
• Vaccination of horses is the most effective way to help manage HeV disease. Vaccination of horses provides a public health and work health and safety benefit by reducing the risk of HeV transmission to humans and other susceptible animals. However, whenever HeV infection is suspected, even in vaccinated horses, appropriate biosecurity precautions, including personal protective equipment (PPE), should be used as no vaccine can provide 100% guaranteed protection.

Factors to consider before making direct contact with the patient

Patient location

Proximity of flying fox roosts

You should consider HeV wherever horses and flying foxes are in proximity to each other. Known flying fox roosts in the locality have been demonstrated as an additive factor for HeV spill-over risk.

Keep in mind that flying fox roosts vary every year, both in the population and in the prevalence of HeV infection. Give greater consideration to roosts with black and/or spectacled flying foxes, as they are more likely to excrete HeV.

Find maps of flying-fox roost locations or an interactive flying-fox web viewer.

The absence of noted flying fox activity does not remove the risk of HeV infection in horses. Smith CS (unpublished data) found a statistically significant increase in the risk of equine cases within 7km of a known roost; however, a 40km foraging 'footprint' was identified in another risk assessment study (Smith et al. 2014). However, during the Bowen incident (2008-09), no roosts were mapped within 50km of the spill-over site (McFarlane et al. 2011).

History of the area

You should also take previous incidents in the area into consideration. Analysis of past events has identified areas with a higher prevalence of incidents. However, the interplay between the climate, location and the reservoir species should be taken into account (i.e. these areas are most strongly correlated to species densities of black and spectacled flying-foxes) (Smith et al. 2014).

Find a summary of HeV incidents, including general locations.

Time of year

Don't use season as a risk criterion on its own. Seasonality has been identified in South East Queensland and northern New South Wales (NSW), but this winter peak is much less evident in other regions.

All regions sampled in Queensland (Field et al. 2015) show a similar background of 'endemic' infection. In the southern Queensland/northern NSW and central NSW regions, there has historically been a strong winter epidemic pattern.

One study did demonstrate an association with the dry season, May to October, with lower temperatures and rainfall (McFarlane et al. 2011). A more recent study (Martin et al. 2018) analysed risk based on latitude. It concluded that there are 2 distinct regions:

• above latitude -22° (approximately in-line with Claireview, 220km north of Rockhampton), spill-over is not affected by seasons
• below latitude -22°, spill-over risk increases from April to October.

Patient factors

Vaccination history

Vaccination of horses is the most effective way to help manage HeV disease. Whenever HeV infection is suspected, even in vaccinated horses, appropriate biosecurity precautions, including PPE, should be used as no vaccine can provide 100% guaranteed protection.

Acute versus chronic presentation

HeV infection in horses typically causes an acute illness that is rapidly fatal.

Clinical signs

There are no pathognomonic signs that define HeV infection in horses. Horses infected with HeV have shown variable and sometimes vague clinical signs. There is a range of clinical signs recorded from confirmed cases.

Husbandry

There are a number of measures horse owners can take to reduce the risk of horses becoming infected. Attending veterinarians should also take these measures into consideration when assessing a case.

References

Field, H, Jordon, D, Edson, D, Morris, S, Melville, D and Parry-Jones K 2015, 'Spatiotemporal aspects of Hendra virus infection in pteroptid bats (flying foxes) in Eastern Australia', PLOS ONE 10(12): e0144055. https://doi.org/10.1371/journal.pone.0144055

Smith, C, Skelly, C, Kung, N, Roberts, B, Field, H 2014, 'Flying-foxes species density – a spatial risk factor for Hendra virus infection in horses in Eastern Australia', PLOS ONE 9(6): e999965. https://doi:10.1371/journal.pone.0099965

McFarlane, R, Becker, N, Field, H 2011, 'Investigation of the climatic and environmental context of Hendra Virus spillover events 1994-2010'. PLOS ONE 6(12): e28374. http://doi.org/10.1371/journal.pone.0028374

Martin, G, Yanez-Arenas, C, Plowright, R.K, Chen, C, Roberts, B, Skerratt, L.F 2018, 'Hendra Virus spillover is a bimodal system driven by climatic factors', EcoHealth. https://doi.org/10.1007/s10393-017-1309-y

Avoid contact with a sick horse that is showing clinical signs when Hendra virus (HeV) is a possible diagnosis. If you must have contact, assess and manage potential HeV risks. Adopt standard precautions and airborne precautions, and enhanced biosecurity.

Isolate the horse

Isolate the horse from humans, other horses and other animals. Put steps in place so that the public cannot access the horse. Keep non-essential people (including children) away from the horse.

Limit procedures

Consider limiting veterinary procedures to obtaining samples, providing immediate treatment and attending to the horse's welfare.

Avoid high-risk procedures that could result in a high level of exposure to the horse's blood, tissues, respiratory secretions and other body fluids.

Ensure sharps safety

Never recap a used needle, and consider using safety-engineered sharps, such as retractable blood collection systems, to minimise the risk of sharps injuries.

Manage the risk to others

Ensure the health and safety of any person who assists you with a veterinary assessment, procedure or treatment (e.g. the person holding the horse). Make sure that the person:

• is properly protected and supervised, and follows infection control precautions
• wears appropriate personal protective equipment (PPE).

Consider using a trained veterinary professional (e.g. a veterinary nurse) to assist you instead of a non-veterinary person, such as the horse owner.

If a potential HeV case needs ongoing treatment before test results are received, you should conduct a risk assessment to ensure the health and safety of the person administering the treatment.

Don't ask non-veterinary staff to administer invasive treatments, including giving injections, until HeV is excluded. Anyone who has close contact with the horse to administer a treatment should follow appropriate infection control precautions, including wearing PPE, safe sharps handling and disposal, hand hygiene and decontamination of themselves and equipment.

You should also provide them with any information, instruction, training or supervision that is necessary to ensure their health and safety.

Manage accidental contamination

If there is accidental contamination with the horse's blood and/or body fluids or a needlestick (sharps) injury, take the following precautions:

• If blood, body fluids or excretions contaminate unprotected skin or involve a cut or puncture wound, wash the area with soap and water as soon as possible.
• If the eyes are contaminated, gently but thoroughly rinse open eyes with water or normal saline for at least 30 seconds.
• If body fluids get in the mouth, spit them out and rinse the mouth with water several times.
• Seek medical advice about possible exposure to HeV.

Contact with an animal with confirmed HeV infection

An animal with confirmed HeV infection should be managed very carefully to prevent the transmission of infection to people and other susceptible animals.

Biosecurity Queensland will work in collaboration with the animal owners and relevant private veterinary practitioners to implement actions to manage the incident.

These actions can include:

• stringent biosecurity and work health and safety measures to limit contact between potential sources of HeV and susceptible animals and humans
• controlling the movement of animals and objects that pose a risk of disease transmission
• epidemiological investigation, tracing and exposure assessment to assess the likelihood of the transmission of HeV to other susceptible animals
• laboratory testing of animals assessed as being close contact animals
• monitoring the health of animals assessed as being close contact animals
• ensuring communications and engagement, informing and addressing the concerns and needs of industry and the community.

Read the Australian Veterinary Association's guidelines for veterinary personal biosecurity.

Unplanned contact with a suspect horse

A veterinary practice investigation procedure for HeV should address the risk of unplanned contact with a suspect horse.

You should compile a dedicated field kit for managing possible HeV cases (including PPE, cleaning agents, disinfectants, sampling equipment and waste disposal bags). This will provide veterinarians with ready access to the equipment needed to protect themselves and others against exposure in situations where there is no prior warning.

If HeV is suspected during routine work where no specific precautions have been taken

• Minimise exposure. Withdraw to a safe area and instruct others to do the same.
• Assess the degree of exposure and use soap and water to wash off contamination - shower if necessary and possible.

Before proceeding with the case:

• assess whether it's safe to re-enter the 'hot' area (i.e. the area where HeV contamination may be present) to sample the horse. Only continue with the investigation if it's safe and the PPE is adequate
• contact Biosecurity Queensland (13 25 23) for advice, as required.

Hendra virus (HeV) was first isolated in 1994 in horses at a racing stable in Hendra, Brisbane.

The table below shows the location and date of each confirmed and possible HeV equine case in Queensland and New South Wales, including clinical signs, observations in horses and other relevant information.

*The clinical signs listed are taken from laboratory testing submission forms or media releases. Not all information for all cases was readily accessible to Biosecurity Queensland.

Take strict precautions for yourself and anyone assisting you when collecting samples for Hendra virus (HeV) testing. Only take samples if the risk of exposure to yourself and others can be adequately managed.

Samples may need to be taken from live and dead horses, so a veterinary assessment of the associated risks is required. Dead horses can be sampled adequately for HeV testing without conducting a complete necropsy, which is a very high-risk activity—particularly on recently deceased animals.

It's the horse owner's responsibility to pay for transporting samples to Biosecurity Queensland's Biosecurity Sciences laboratory (BSL). Biosecurity Queensland will meet all laboratory testing costs to test samples for HeV in diagnostic cases (Note: charges apply for HeV health testing).

Private veterinary practitioners should make the final decision about whether to collect samples and submit them for laboratory testing and, where required, get advice from Biosecurity Queensland.

Taking samples for diagnosis

Preferred samples for diagnosis (from most preferred to least preferred) of suspect cases are:

• EDTA blood: ensure tubes are filled to reduce the risk of anticoagulant concentration interfering with test results.
• swabs: nasal, oral, rectal and vaginal. Note the following
  • Nasal swabs may show infection earlier than blood or other clinical samples, and together with EDTA blood is the minimum sample requirement for exclusion in diagnostic cases.
  • Swabs should be transported in virus transport medium (VTM). A small amount of saline (1–2ml) can be used to prevent swabs from drying out if VTM is not available.
  • A urine-soaked swab taken from the ground immediately after urination can also be helpful.

If whole blood in EDTA is not available, polymerase chain reaction (PCR) testing may be conducted on the blood clot.

Dead horses can be adequately sampled for HeV exclusion without conducting a complete necropsy. We recommend the following samples

• swabs (as above)
• blood clot obtained by cutting down onto the jugular vein
• submandibular lymph node (chilled).

Submitting a combination of EDTA blood, nasal, oral and rectal swabs should be sufficient for detecting HeV infection in a very high proportion of HeV-infected horses.

BSL doesn't undertake routine biochemistry/haematology testing. It's best to collect duplicate blood samples that you can keep safely and securely at your veterinary clinic for in-house or private laboratory testing, once HeV is excluded.

How to submit samples

HeV testing is conducted at the Biosecurity Sciences Laboratory (BSL) in Coopers Plains. Samples for HeV exclusion testing should be submitted directly to BSL, as this will achieve the shortest turnaround times.

Specimen advice sheet

A fully completed specimen advice sheet (SAS) must accompany all submissions. If you want to receive diagnostic testing for HeV at no charge, you must include a full clinical history and vaccination status of the animal. Ensure that the SAS is packed on the outside of the samples and that it clearly indicates a request for HeV exclusion.

Cut-off and turn-around times

Typically, 1 round of HeV PCR laboratory testing is run each weekday at BSL, starting at 2 pm. In most circumstances, samples received at BSL before this time will achieve a result on the same day. Samples received after this time will be tested the next business day.

Phone ahead to let BSL know if you intend to submit samples so arrangements can be made to facilitate testing, and so you can be contacted if the samples are not received by the cut-off time. You must provide a direct after-hours contact number on the SAS if you want to be notified of results by phone on the same day, as the results of testing are typically available around 5 pm.

Packaging and transporting HeV exclusion samples

When submitting HeV exclusion samples:

• There are packaging requirements that must be met to transport biological samples by road and rail (surface) or air. The contents should have no chance of escaping from the package under normal conditions of transport.
• Everyone responsible for packaging and transporting biological samples must be appropriately trained and their competency assessed for the task that they are to perform. Training from an accredited provider is required for the packaging of some categories of samples.
• Some courier companies will provide a complete service (i.e. they will come to a veterinary practice, pack and dispatch the samples correctly). Veterinary practices should establish an account with their chosen courier service so that samples for HeV testing can be dispatched for testing without delay.
• For transport of all pathology samples and associated material by air or surface transport methods, the contents must be triple packaged in a primary receptacle, secondary packaging and outer packaging.

Contact BSL if you have any queries on sample submission.

Urgency of HeV testing for horses

Urgent testing for HeV diagnosis/exclusion may be conducted under certain circumstances.

If urgent testing is required during business hours, veterinarians should contact the Biosecurity Queensland duty pathologist at BSL to discuss the situation.

After hours, contact the Emergency Animal Disease Hotline on 1800 675 888 and discuss the situation with the Biosecurity Queensland veterinary officer.

The decision to conduct urgent HeV testing is made following discussion between the submitter and relevant Biosecurity Queensland staff. This may include the Biosecurity Queensland veterinary officer and/or the on-duty pathologist.

Requests for urgent testing will be assessed on a case-by-case basis. Reasons that may necessitate urgent testing for HeV include:

• significant human exposure to body fluids of highly suspect HeV-infected horse(s)
• exposure of large numbers of animals to the body fluids of highly suspect HeV-infected horse(s).

BSL specimen receipt is open for sample submission Monday to Friday only (8 am–5 pm). Don't send samples to be delivered to BSL outside these times without first consulting with the on-duty pathologist. Horse owners are responsible for all costs associated with weekend delivery of samples for urgent HeV testing (Note: courier charges for time-definite deliveries can be significant).

HeV tests

Polymerase chain reaction (PCR) test

This is the primary test conducted at BSL for exclusion of HeV infection, particularly in acutely sick animals. PCR tests can be conducted on blood, swabs and tissue samples. They detect the direct presence of the genetic material of the Hendra virus in a sample and can detect live or dead viruses, but cannot differentiate between them.

A positive result indicates the presence of viral genome in the sample, but does not confirm that the virus is viable and infectious. When accompanied by relevant clinical signs, a positive PCR test result is interpreted to mean an animal has an existing HeV infection.

A negative PCR test result needs to be interpreted in relation to the health of the animal and the broader epidemiological context.

Enzyme-linked immunosorbent assay (ELISA) test

This is not routinely used at BSL to exclude HeV infection in acutely sick horses, particularly if they have a history of vaccination. ELISA tests are conducted on serum samples to detect the presence of antibodies and are regarded as a screening test.

A negative ELISA result is a reliable indicator that a horse has not been previously exposed to HeV.

Being a screening test, non-negative ELISA test results, including nonspecific reactor results, require confirmatory testing by virus neutralisation testing (VNT).

A positive result could be due to past infections or vaccination with the production of neutralising anti-G antibodies. Differentiating these requires differentiating infected from vaccinated animals (DIVA) testing.

Virus neutralisation test (VNT)

VNTs detect the presence of HeV antibody in a blood sample and are used to confirm non-negative results from ELISA screening tests.

A positive VNT indicates the animal is seropositive to HeV either from infection or vaccination.

The antibody response to infection or vaccination takes time to develop, and this should be considered when interpreting negative results. VNT testing can only be conducted at the Australian Animal Health Laboratory (AAHL) in Geelong.

Differentiating infected from vaccinated animals (DIVA) testing

Development and assessment of DIVA tests is an area of active investigation.

Interpreting a panel of tests that detect the G glycoprotein or other HeV proteins will help us to differentiate between:

• serologically positive animals due to vaccination
• serologically positive animals due to infection.

DIVA testing can only be completed at AAHL in Geelong.

Also consider...

• Read general information about the Hendra virus.

Veterinary practices should develop and implement infection control and biosecurity procedures to manage the risks associated with investigating and sampling potential Hendra virus (HeV) cases.

Procedure outline for HeV case investigations

Normal practice management should include thorough preparation before a veterinarian conducts a field investigation of potential HeV. Plans, procedures, appropriate equipment and training are all required to assist in the safe, timely handling of investigations.

You can use a laminated procedure or plan for HeV case investigation as a checklist to ensure you address all key elements. This should include a decontamination procedure before leaving the property.

Always take appropriate precautions based on any suspicion of HeV, even with vaccinated horses; don't wait for confirmation.

Steps to consider before investigating a horse with potential HeV infection

You can take the following steps before investigating a horse with potential HeV infection. You should also source extra information to suit your particular situation:

1. Obtain as much history as possible from the client's initial phone call or enquiry and make an initial case assessment. To do this, you need to:
   • ask if the horse is vaccinated against HeV, or check the HeV Vaccination Registry.
   • be familiar with the various HeV clinical presentations.
2. If you suspect HeV before you enter a property, know the precautions and procedures to follow. These include:
   • work health and safety precautions to ensure the health and safety, as far as is reasonably practicable, of yourself, workers and others who are assisting you
   • infection control and biosecurity precautions
   • the choice of personal protective equipment (PPE) and disinfectants used
   • entry and exit procedures
   • appropriate biosecurity advice for clients.

   If you don't suspect HeV before the examination of a horse, know the immediate steps to take to minimise the risk and exposure to you and others. Learn more about unplanned contact with an ill horse that may be infected with HeV.

3. Develop a sampling protocol.
   • Prepare a HeV sample collection procedure that includes:
     • samples required and the safest methods of collecting them
     • necessary equipment.
   • Prepare a HeV sample dispatch procedure which explains:
     • how to safely pack samples, or which couriers will provide this service
     • where to send samples (send HeV samples to the Biosecurity Sciences Laboratory, not a private laboratory)
     • which couriers will transport samples, and which couriers provide an out-of-hours service.
4. Develop a dedicated field kit to manage possible HeV cases. Include items such as:
   • PPE
   • cleaning agents and disinfectants
   • sampling equipment
   • waste disposal bags
   • a sharps container.
5. Prepare biosecurity advice to give to clients. This information will explain what owners and managers involved with managing the case and the site should do.
6. Prepare advice about the disposal of carcasses. This may include:
   • the disposal method of choice for the area (deep burial on site if possible)
   • advice for owners/contractors for safe disposal and to prevent disease spread.
7. Prepare a list of contacts you'll be required to liaise with, and record the contact details.

Training

Training is an important part of the HeV investigation plan, ensuring that all relevant people are competent to manage a HeV investigation. We recommend that you keep records of all training conducted.

If PPE is not routinely used, training will be required. A number of PPE suppliers provide training in the correct fitting and use of PPE. The Australian Veterinary Association has produced an online video, Suit up! Personal protective equipment for veterinarians about PPE, including how to safely put on and take off full PPE.

The packaging of samples for laboratory testing may also require training (available from private providers) to ensure diagnostic samples comply with transport requirements. Alternatively, you can decide to use a courier company (recording this in the procedure) that will provide a packing and transport service.

Veterinarians should establish entry and exit procedures (for routine property visits or for possible Hendra virus (HeV) investigations) to provide a clear process for applying infection control procedures, including personal protective equipment (PPE), so that personal safety and disease control are managed.

Key steps:

• Define the edge of the hot zone (i.e. the area where HeV contamination may be present).
• Select a site at this edge that has good access from the cold zone.
• At this site, establish an entry/exit decontamination site. This site allows you to prepare safely in the cold zone, including donning PPE, preparing sampling equipment and preparing disinfectant solutions.
• Only enter the hot zone when you're fully prepared.
• The arrangement of this site then allows you to exit through a decontamination process that protects personal safety and prevents disease spread.
• If repeat visits are likely, or if other colleagues may visit, mark the site clearly so the same site is used each time. This prevents other people from setting up on potentially contaminated ground.
• Recommend this process to other people who may need to access the hot zone.

Detailed equipment list and procedure

Read the more detailed Hendra virus equipment list and property entry and exit procedure (PDF, 352KB).

If Hendra virus (HeV) is suspected in a client's horse, it's important to give them sound biosecurity advice to ensure the health, safety and welfare of people and other animals.

As an attending veterinarian, you need to advise the client of the zoonotic potential of HeV and the steps they can take to manage the risk of exposure to themselves and others.

Steps horse owners can take to minimise the risk of HeV exposure

Horse owners should:

• isolate the sick or dead horse from all people, all other horses and all other domestic animals on the premises, and from public access areas where possible
• advise neighbours that a horse on their property is being investigated for HeV infection
• observe the sick horse from a distance and notify the veterinarian if there's any change in the behaviour or health of any other horse on the property.
• avoid close contact with the sick horse.

If your client must have close contact with a sick horse where HeV hasn't been ruled out, you should give them advice about appropriate infection prevention and control measures, for example:

• avoid invasive treatments
• arrange activities so that unaffected horses are handled first and have contact with the sick horse last
• cover cuts and abrasions with a water-resistant dressing
• put on appropriate personal protective equipment (PPE) before approaching the horse
• after handling the horse, remove and dispose of PPE carefully, making sure there's no contact with the facial area, particularly eyes, mouth and nose
• wash your hands with soap and water and dry them well, or use hand wipes and a waterless alcohol-based hand rub immediately after removing PPE
• carefully remove any clothing contaminated with a sick horse's body fluids.

If clients have handled a sick horse, they should follow these steps before having contact with other horses:

• wash off any contamination with plenty of soap and water
• shower and wash hair
• change clothes and footwear.

Also advise the client to stop or limit:

• horse movements on and off the property
• movements of horse products (such as manure) and equipment (such as tack, dental equipment) off the property
• visits from horse practitioners (such as farriers or equine dentists) and to advise visiting horse practitioners who must have close contact with the horse about the potential HeV risk.

When disposing of a dead horse, the disposal contractor should be informed that the horse is suspected of being infected with HeV. Appropriate precautions should be taken.

Health concerns and medical assistance

Let clients know that they should seek medical advice if they're at all concerned about possible exposure to HeV. They can contact:

• their local GP
• their nearest Queensland Health Public Health Unit
• the Queensland Health 24-hour hotline on 13 HEALTH (13 43 25 84).

Biosecurity Queensland will contact Queensland Health if HeV is confirmed or highly suspected. Queensland Health will decide if any people require monitoring or medical assistance. To make this assessment, Queensland Health will work with the veterinarian and the horse owner to identify the people they may need to contact.

Apply the precautionary principle to ensure personal safety and prevent zoonotic risk.

An infected horse can excrete Hendra virus (HeV) in nasal or nasopharyngeal secretions for several days before the onset of clinical signs. A horse with severe clinical signs poses the greatest transmission risk to other horses and humans through a range of body fluids and excretions.

HeV is often diagnosed retrospectively in horses after human exposure has occurred. This reinforces the need to consider HeV early in the investigation phase, and to establish appropriate infection control procedures for day-to-day situations.

Vaccination

A registered vaccine is available for horses. Vaccination of horses is the most effective way to help manage HeV disease. Vaccination of horses provides a public health and work health and safety benefit by reducing the risk of HeV transmission to humans and other susceptible animals.

Whenever HeV infection is suspected, even in vaccinated horses, appropriate biosecurity precautions including personal protective equipment (PPE) should be used as no vaccine can provide 100% guaranteed protection.

Standard precautions against infection

Standard precautions are a set of basic infection control practices used to prevent transmitting diseases through contact with blood, tissues, body fluids, non-intact skin and mucous membranes. You should use these measures when providing care to any animal. This includes all horses, even if they've been vaccinated for HeV, or don't appear infectious or symptomatic.

Standard precautions include, but are not limited to:

• hand hygiene
• aseptic non-touch technique
• sharps safety
• clinical waste management
• laundry management
• standard decontamination procedures
• appropriate reprocessing of equipment
• routine environmental cleaning.

In particular, you should:

• take precautions to prevent any direct contact with, splash back of, or accidental inoculation with blood, body fluids or excretions
• cover any open wounds with a waterproof dressing
• ensure sharps safety, never recap used needles and always use a sharps container to avoid sharps injuries
• perform hand hygiene
  • after any exposure to blood and body fluids
  • after contact with a horse, its environment and equipment, and before moving on to other activities
  • during and after removal of PPE
• adopt appropriate cleaning processes for the environment and equipment, and reprocess reusable equipment used in clinical procedures in accordance with AS 4187
• ensure the safe handling, transport, storage and disposal of clinical waste (including sharps). Sharps must be disposed of in a container specifically designed for the disposal of sharps
• ensure the safe handling, transport, storage and cleaning of contaminated clothing and other laundry
• ensure the safe handling, transport, storage and disposal of pathology specimens
• ensure the safe handling and disposal of animal excreta
• maintain stable hygiene and conduct environmental cleaning using appropriate cleaning agents and disinfectants
• wear PPE.

Airborne precautions

You should adopt standard precautions as well as airborne precautions for procedures that are invasive or that generate aerosols. This includes procedures of the respiratory tract, and other high-risk procedures, such as endoscopy of the upper and lower respiratory tract, dentistry using power floats, necropsy, broncho-alveolar lavage and nasal lavage.

Airborne precautions are additional, transmission-based precautions to prevent inhalation of contaminated aerosols and dusts. They include:

• work practices that minimise the generation of aerosols and dust (e.g. avoiding the use of high-pressure water systems for cleaning)
• ventilation controls
• enhanced PPE. The minimum level of PPE for airborne precautions includes a properly fitted disposable P2 respirator.

Personal protective equipment (PPE) is intended to form a barrier between the person and the infectious agent. It may include:

• rubber boots
• splash-proof overalls (long sleeves with a hood) or cotton or disposable overalls with impervious or splash-proof apron
• disposable impermeable gloves (nitrile gloves recommended), double-gloved
• face shield or safety eyewear (to protect against facial splashing)
• a particulate respirator.

PPE responsibilities of veterinarians

Work health and safety legislation requires a person conducting a business or undertaking to ensure that PPE provided to workers is:

• suitable for the work and any hazard associated with the work
• the right size and fit and reasonably comfortable.

The PPE must be maintained, repaired or replaced so that it continues to minimise risk. This includes ensuring that it's clean and hygienic, and in good working order. You should also ensure, as far as is reasonably practical, that the PPE is used or worn by the worker or any other person at the workplace.

To provide the best protection possible, combine PPE with other measures, such as vaccinating horses, HeV planning and preparedness, infection control practices and managing exposure to HeV risks.

Source PPE ahead of time and arrange training in its correct use, storage and maintenance.

If there's a higher level of risk, or a horse is known to be infected with HeV, increase the standard of PPE accordingly.

Using PPE

Always have adequate PPE available at all places where horses are examined. PPE supplies for repeat visits and for those assisting should be available.

Always remove PPE carefully to avoid contamination and perform hand hygiene during and after removing PPE. Decontaminate reusable PPE after use and don't reuse disposable PPE.

The Australian Veterinary Association has produced an online video, Suit-up, about PPE, including correct donning and doffing.

Buying PPE

Discuss your specific safety needs with a supplier of safety equipment to get expert advice and be provided with a selection of products appropriate for individual situations. Alternatively, you can obtain PPE from safety supply stores and most hardware stores.

Heat stress and PPE

We recommend splash-proof PPE rather than impervious PPE. Splash-proof items are usually lighter and better suited to hotter conditions. Impervious (waterproof) PPE, particularly impervious overalls or suits, need to be used with great care as there's a real risk of rapidly overheating, particularly if used in direct sunlight.

Using PPE can create significant heat stress issues. The risk of heat stress should be managed where possible, for example by:

• drinking enough fluids before and during work
• scheduling work times to avoid the hottest part of the day
• using cool clothing and cooling scarves and vests
• using portable shade
• taking frequent rest breaks in cool areas
• rotating teams or use a buddy system,
• knowing the signs of heat stress and stopping work if these signs start to develop.

Respiratory protective equipment

Discuss your specific respiratory protective equipment (RPE) needs with a supplier of safety equipment to get expert advice and products appropriate for individual situations.

A P2 disposable facepiece respirator, or a P2 filter in a half facepiece respirator, is the minimum level of respiratory protection for investigating potential HeV situations where contact with respiratory secretions or aerosols is likely or possible. For a higher level of protection you can use a P2 or P3 filter in a full facepiece respirator, or a powered air-purifying respirator (PAPR).

Note: A standard surgical face mask is not a respirator and won't provide respiratory protection because it doesn't have adequate filtering and/or fitting properties. Don't wear a surgical mask or a dust mask for suspected or confirmed HeV cases as these won't filter bio-aerosols or provide an adequate facial seal.

Training in the use of PPE

Work health and safety legislation requires you to provide workers with information, training and instruction in PPE.

We recommend that you consult a commercial provider about PPE training. Training should include:

• correct donning and doffing procedures (putting on and taking off PPE)
• respirator fit checking
• correct storage, maintenance, cleaning, disinfection and disposal of PPE.

We also recommend that you keep records of PPE training and results of fit testing.

Disinfectants

Specific testing of disinfectant compounds against HeV has not been conducted.

The AUSVETPLAN decontamination manual notes that HeV is a member of Category A viruses. This category of viruses contains a lipid envelope.

The following disinfectants are known to be effective against category A viruses:

• soaps and detergents
• Virkon®
• hypochlorites
• iodophors/iodine
• biguanidines (e.g. chlorhexidine)
• quaternary ammonium compounds.

Others are named in AUSVETPLAN but these require special precautions for their safe use.

Any disinfectants that are hazardous chemicals must be used in accordance with the hazardous chemicals provisions of the Work Health and Safety Regulation 2011.

The Work Health and Safety Act 2011 places duties on people at workplaces for health and safety.

A person conducting a business or undertaking (PCBU) has a primary duty of care to ensure, as far as reasonably practical, the health and safety of themselves and workers (e.g. employees, students, trainees, contractors, sub-contractors and volunteers).

The same duty also applies to any other people who may be at risk from work carried out by the business or undertaking (e.g. clients).

If you are a veterinarian or a practice principal, you should ensure the following work health and safety (WHS) precautions:

• Manage the risks to health and safety from Hendra virus (HeV). Safe Work Australia's How to manage work health and safety risks code of practice gives guidance on risk management.
• Develop and implement a plan for responding to suspected HeV cases. This should include minimising the risk to veterinarians, veterinary nurses and others (e.g. clients).
• Develop and implement supporting HeV policies, procedures, equipment and training.
• Adopt recommended infection prevention and control and biosecurity precautions to protect veterinarians, veterinary nurses and others (including clients) against exposure to HeV risks.
• Provide biosecurity advice to clients.
• Discuss HeV vaccination with horse owners. Vaccination of horses provides a public health and work health and safety benefit by reducing the risk of HeV transmission to humans and other susceptible animals.

Work-caused infection with HeV is a notifiable incident. If this happens, you need to notify Workplace Health and Safety Queensland (WHSQ).

For more information, visit the WHSQ website or contact WHSQ on 1300 362 128.

Warning: Safety of people is the primary consideration when investigating potential Hendra virus (HeV) cases in animals. If you are concerned about your health, you should:

• seek medical advice and contact your local GP
• contact your nearest Queensland Health Public Health Unit
• contact the Queensland Health 24-hour hotline on 13 HEALTH (13 43 25 84).

Apply the precautionary principle. An infected horse can excrete HeV in nasal or nasopharyngeal secretions for several days before the onset of clinical signs. A horse with severe clinical signs poses the greatest transmission risk to other horses and humans through a range of body fluids and excretions.

Warning: Hendra virus (HeV) infection of humans is rare, but it is a serious disease that can be fatal. Infection has occurred from high levels of exposure to the respiratory secretions and/or blood from horses infected with HeV (both live horses and dead horses at necropsy examination). Great care is needed to ensure the personal safety of the veterinarian and others who may be involved.

Learn more about precautions to take when Hendra virus is suspected.