1. Nigel Perkins Managing Hendra risk AusVet Animal Health Services Thoroughbred Breeders Queensland Association Gatton 25 October 2009

2. Hendra incidents

3. Hendra virus in horses  Underlying effects on cells is via virus damaging endothelial cells  Clinical signs may then depend on which organs are most severely affected first (resp vs GIT vs neurological etc)  Signs likely to be variable & non-specific, esp early  Hendra is rare and most cases that show signs consistent with Hendra will NOT be cases  Tomorrow's case may not look like priors  It seems unlikely that we will be able to better pick Hendra cases earlier in the future

4. Exposure risk  Hendra virus is present in fluids & tissues in infected horses blood, saliva, nose/mouth, urine/faeces, tissues Virus is shed from late incubation and through clinical stages to death Virus shedding/secretion maximal around the time of death  Splash/droplet risk and not aerosol  Risk depends on: horse factors: stage of infection, localisation of virus, amnt being shed… What procedures are being done, level of PPE & biosecurity

5. Viral shedding

6. Previous human cases & exposures  1994: Hendra virus was unknown no precautions taken against Hendra  2004 (Cairns) post mortem, Hendra not suspected Vet later developed signs & tested positive Horse not suspected until after Vet tested positive  2008 (Redlands) Vet & Vet nurse infected Horses being treated, examined, handled etc prior to Hendra being suspected

7. Previous human cases & exposures  2008 Proserpine Vet suspected Hendra when client reported deterioration & death of the horse Vet called DPI and received instructions – used PPE & restricted necropsy Horse positive & no human infection  2009 Cawarral Vet infected while dealing with a sick horse without suspecting Hendra at the time  2009 (Bowen) Vet took precautions at first visit to a suspect horse (Sept) – Hendra Then an earlier sick horse that had died the month before also tested positive

8. Other possible human exposures Redlands -2 people infected -Many more people potentially at risk of exposure through interacting with Hendra horses before or after the horses died Proserpine -horse & property owners Cawarral -property owner, staff, private vets

9. Possible exposure pathways for people 1.Horse that is severely ill or dead with signs consistent with Hendra Staff/Vet concerned about Hendra Take precautions before approaching the horse 2.Horse presents with non-specific signs (mild, severe or sudden death) Hendra is not suspected when Staff first approach horse Risk of exposure depends on activities/procedures 3.Horse that is apparently healthy yet is incubating Hendra Staff/Vet involvement for other reasons Exposure risk much more variable & generally lower

10. >70% of all cases occurred prior to QPIF involvement

11. What happens when QPIF get involved?  QPIF generally involved once a Hendra positive test has been obtained  Risk management generally improves dramatically Quarantine declared Horse movement stopped or controlled In contact animals tested Biosecurity measures implemented: entry/exit, PPE, disinfection, decontamination, restricted horse interaction QH involved for human risk management & testing

12. Different risk periods BEFORE Hendra is diagnosed Horse showing signs May or may not be Hendra To date, owners/vets have been poor at taking effective precautions little or no PPE Likelihood of Hendra is LOW Risk of exposure if Hendra is present is HIGHER All human cases to date have occurred in this scenario AFTER Hendra is diagnosed Hendra test positive QPIF involved quarantine, PPE, … Likelihood of Hendra being present is HIGH Risk of exposure is LOW because of biosecurity measures no human cases have occurred in this scenario

13. Major risk management issues for owners/staff  Prior to confirmation of Hendra in a horse QPIF not involved Major period of risk for staff/owners & vets Need to develop plans to manage exposure risk for day-to- day work with horses  After confirmation of at least one Hendra case on your property QPIF involved, quarantine declared Shared responsibilities: -QPIF working on Hendra testing & euthanasia of positives -Farm staff still responsible for day-to-day activities including care & welfare of horses for reasons other than Hendra monitoring/testing -Farm staff & PVP may be involved in taking samples/observations

14. Managing exposure risk given what we know now  Everyone who contacts a horse is bearing some risk – shared responsibility  People involved in more invasive procedures (vets, vet nurses, dentists, …) bear higher risk because of the activities & associated contact with potentially infectious material

15. How can we assess risk?  Picking horses that have higher or lower risk horses that we think have Hendra virus would be at high risk Horses that we think don’t have Hendra virus would be at low risk BUT  Horses that are infected with Hendra virus show variable & often vague clinical signs that could be due to other conditions and in fact are more likely to be due to other conditions (fever, off feed, depression, colicy, respiratory, neurological, …) AND, can shed Hendra virus before they show any clinical signs of illness

16. Procedures-based risk  Activities or procedures with higher associated risk exposure to blood, urine, nasal/oral secretions, internal organs, … Biosecurity: hygiene, PPE, disinfection, …  Activities associated with lower risk lameness, physical exam, … Reduced level of biosecurity Focus on personal hygiene

17. Workplace Health and Safety  Need to be aware of responsibilities under state legislation to employees to people coming onto the property to do work (vets) others  Risk management plans  Training  Equipment (PPE)

18. Risk management  Develop a risk-based approach to horse practice  Risk management has to be implemented prior to the time when Hendra might be suspected  Rapid tests are not a solution to initial veterinary risk management  Depends more on identifying: activities or procedures with associated risk horse history & signalment

19. Risk management  Very low risk healthy horses & simple interaction (no contact with biological fluids) risk management based on person hygiene  Low to moderate risk healthy horses & human interaction with some risk of contact with biological fluids PPE (barrier protection) & personal hygiene  Moderate & higher risk sick horse showing variable signs PPE (barrier protection) & personal hygiene & procedures based risk assessment restrict people who are involved get veterinary help

20. Risk on a confirmed property  Day to day tasks and health & welfare care continues  Add Hendra monitoring & full PPE and entry/exit procedures  Minimise contact with horses  Movements/flow from low risk first to high risk last  Cant move horses very much if at all  How much time & what procedures can be safely done in full PPE?  How to manage non-Hendra health needs (foalings, injuries,…)  How to manage staff fatigue, rosters, get sufficient labour etc  Provision of training and a framework for making decisions

21. Complexities of managing risk  Concepts seem rational  Practical difficulties seem immense if hendra is listed as a differential then DPI vet must be notified. What quarantine/response measures should be imposed while waiting for a test result? how do we manage all the ongoing cases – cut legs, foalings, injuries, colics etc & try to manage Hendra risk? what are the ramifications for farm day-to-day management?

22. Future  Simple PPE & biosecurity that can be used routinely  Awareness campaigns for all stakeholders  Risk planning facilitated & aided by industry bodies & implemented by every horse operator  Training in PPE & biosecurity for those that need it  Work with QPIF (DPI) & other stakeholders to manage the notification & response alerts  Research to address issues that will help manage risk understanding spillover events & how to reduce risk behavioural research on adoption of change Post-exposure treatment testing: test availability, speed vaccine others