Thursday, May 2, 2013

Hendra virus: A diary 
by Katharine Sharon

This is the (fictitious) diary of Rosemarie Wilson, a race horse trainer in Queensland, Australia.  In the summer of 2012, Wilson lost one of her four horses to Hendra virus.  Here is the account she kept as she experienced it:
Created by Katharine Sharon
            July 12, 2012:  I’ve been instructed by Dr. Benton to keep this diary of events for insurance purposes since all four of my race horses are insured.  It’s been a long day.  Big Red didn’t eat his breakfast this morning and seemed off – depressed.(1)  He is training well and enjoying his paddock time, but thinking back, he seemed a bit lackluster yesterday, too.  I moved him to the stall at the end of the courtyard away from the other horses and called Dr. Benton just to be safe.  By the time Doc got here – about 3 p.m. – Big Red was obviously uncomfortable, breathing a little hard and seemed disoriented.(1)  The muscles over his rump and around his shoulders twitched.(1)  Doc took one look at the colt and said that due to the outbreak of Hendra virus (HeV) nearby, he had to consider it a possibility.  Doc said it was probably overkill, but we both dressed in plastic overalls, boots and gloves, and then put on protective glasses and a mask.(2)  Doc also had me place a footbath outside Red’s stall.(2)  Doc completed a physical exam and found Red had a fever (102°F), high heart and respiratory rates (64 bpm and 36 bpm, respectively) and said his “oral mucous membranes were injected” (they were bright red).(3)  Doc took three tubes of blood from Red to send to the government lab to test for HeV.  He said they usually run three tests: PCR, indirect ELISA and virus isolation.(4,5)  He then took nasal swab samples from each nostril, and also swabbed Red’s mouth, rectum and conjunctiva.(5)  He also gave Red a shot of banamine, which seemed to help the colt get comfortable.(6)
            Doc said he’d also run a few standard tests – CBC and chemistry – to cover the basics.  We should have results late tomorrow afternoon.  Doc gave me a pamphlet with information on HeV (see above) and instructed me to use the highest biosecurity standards – if we had to handle Red we should wear protective gear and wash our hands afterward; no horses should go on or off the farm (he explained that this is a self-imposed quarantine but he highly recommended taking the precaution); keep the other horses away from Red; and handle Red only after dealing with the healthy horses first.(4)  He stressed that Red’s definitive diagnosis is yet to be confirmed, but he wanted me to take all precautions to ensure the safety of the people and horses on the farm.  Because he believed this to be a possible HeV case, Doc said he had to notify the regional government veterinarian.(4)
I felt compelled to tell Dr. Benton that I didn’t know of any flying fox colonies in my neck of the woods.  I also showed him my two paddocks – I wanted him to see that only the far side of the paddocks had trees on the other side of the fence and the water buckets were far from those trees.(9)  He assured me that my farm was well managed, but said that HeV is possible even at the best of farms because all horses have to do is ingest the droppings, birthing excretions or other bodily fluids of the bats.(5)  He told me not to panic and reminded me again that he was being extra careful.
After Doc left, I called Dottie Richardson, Big Red’s owner, who wanted to come out straight away to see her horse.  I had to tell her to stay where she was – no sense in possibly exposing the octogenarian to HeV.  I could hear the heartbreak in her voice.  I also spoke with my team – Jeff, my assistant trainer, and Trudy, my groom.  I told them that they had to protect themselves as much as possible until we knew what we were dealing with – I explained the importance of suiting up when working with Red, but I also said not to go near him if they didn’t have to.  I sent them home and told them to be mindful of how they felt – to look for flu-like symptoms, headaches or other signs of illness that Doc told me about.(7)
Big Red winning at Ipswich in June. (www.testcountry.org)
I called Doc later to ask a few more questions: Trixie gets turned out in the same paddock as Red, though not at the same time – did I have to worry about her?  Red and Subtle Foe share the same bridle, but we wash the bit between horses – how likely is it that he too will come down with whatever Red has?  Doc told me the literature showed that HeV usually presents in one horse in a paddock situation(10) and that contaminated tack could transmit the virus(5), but reminded me that we didn’t know if we were dealing HeV definitively.
July 13, 2012:  I was awakened at 3 a.m. to a ruckus in the stable across the yard.  Big Red was thumping about his stall.  I suited up and tried to catch him, but the colt was distraught – I don’t think he could see me.  I called Dr. Benton who came right away.  With the two of us suited up, Doc was able to examine the colt and found his heart and respiration rates to be 120 bpm and 100 bpm, respectively, a fever of 104.8°F, abnormal swelling around his throatlatch area and that Red was blind.(1,3)  Doc tried sedating Red and gave him some more banamine, hoping to help calm him down, but it didn’t work.  Red seemed panicky and because he was so unstable and uncoordinated, he fell.  He was too weak to get back up.(3)  Doc suggested I call Dottie and tell her that euthanasia was his recommendation.  Once I had explained the situation to her and how painful and scared her horse was, Dottie gave the go ahead.  Big Red died at 4:30 a.m.  Doc called one of his friends at Queensland Biosecurity division who had previously handled HeV cases to receive instruction on getting samples from a necropsy.  Under Doc’s instruction, I dug a hole to bury Red, but made it big enough so that Doc could climb in there and have enough room to get samples to send to the lab.  Doc took pieces of Red’s submandibular lymph node and a blood clot removed from the jugular vein.  He also took swabs from Red’s nose, tongue and rectum.(4,5)  When he was done, I covered the colt with dirt. 
Trixie, Subtle Foe and Imabiter on the gallops at the beginning of June. The
                line of trees in the background abut my two paddocks and one of the samples
                taken from the ground of Big Red's paddock tested positive for HeV.
                (www.an-eventful-life.com.au)
Just to be safe, Doc changed suits, washed up and did a physical exam on all of the horses to make sure he had a baseline for them.  All of the other horses were normal, which made me breathe a slight sigh of relief but I was still worried.  I called Jeff and Trudy and told them the news and said that I would take care of the three remaining horses today. 
Dr. Benton called about 4 p.m. and said that he was on his way to the farm – Red tested positive for HeV.  My heart fell.  I called Jeff and Trudy to tell them more bad news and asked them to come to the farm.  Doc and the authorities arrived about the same time.  I was informed that my farm was under quarantine for at least the next 35 days (the incubation period ranges from 5-16 days and they wanted the farm on lockdown twice as long), during which time no horses could leave or enter the farm.(5)  The authorities also informed me that they would notify local and regional authorities, my neighbors and the race tracks where my horses had run in the previous three weeks (Subtle Foe ran at Ipswich Racecourse last week; Imabiter ran at Mackay Racecourse three days ago; neither Red nor Trixie had run anywhere in that time).(4)  Investigators took samples from the remaining three horses as a baseline and I was told that all animals on the farm will be assessed daily for signs of HeV and intermittently tested for the virus during the quarantine period.(6)  Lastly, Jeff, Trudy and I were instructed to get baseline tests on ourselves, too, since we all had close contact with Red.(4)
While Dr. Benton and the authorities went about posting signs around the property and spraying the driveway down with chlorine, I called the three other owners.  All were understandably alarmed and I did my best to play the role of a comforting friend, but I know my fear and anxiety came through to them.  I then called my neighbors so that I would be the first to tell them, not the authorities.  They were very kind and understanding, considering the situation.
It was late by the time the authorities left and I just pray that no more of my horses have HeV – it would break my heart for the horses and the owners.            
July 14, 2012:  The investigators arrived early, just after I had done the absolute minimum with the horses – fed, watered and hayed.  They went out to the paddocks and took samples from the ground under the trees, testing for flying fox secretions and excrement.(6)  They also told me that two investigators would be back tonight to spend the night under the trees outside the paddock to make observations on flying fox activity – should there be any.(6)
 Soon after the authorities left, my phone started ringing with interview requests from newspapers and TV news people.  I told them to speak to the authorities because I truly cannot muster the energy to deal with them.
Investigators take samples from my paddocks. (www.couriermail.com.au)
For now, Imabiter, Trixie and Subtle Foe  are all seemingly healthy.  They seem a little desperate for the human attention they’re used to getting on a daily basis, but otherwise, they’re eating and drinking well, acting normally and making a mess of their stalls.  Jeff, Trudy and I are also seemingly healthy.  I cannot ask for more.
July 20, 2012: I haven’t written in a couple of days because there’s nothing to report – thankfully.  All horses and people are doing just fine, and subsequent blood tests for HeV have all been negative.  I’m feeling very fortunate.
However, the investigators who took samples from the paddocks called to tell me that Red’s paddock tested positive for the presence of HeV.  The sample was taken from the ground near the trees at the back.  They advised me about removing the trees or moving my paddocks altogether.  I am lucky to have enough land around me that I divided my one large pasture into four paddocks – all of which have no trees anywhere around them.  Doc told me that move was a little drastic, but there’s so little I can do to protect my horses and this is one thing that can make a difference.  Once I add turnout sheds to two of the paddocks, they will be ready for use.
July 30, 2012: All horses are back in work and so are we!  Trixie, Subtle Foe and Imabiter got their last blood test today, but it has been longer than 16 days and so they should have made it through the incubation time by now.  Same goes for me, Jeff and Trudy.  I cannot thank Dr. Benton enough for everything he did during the outbreak – he was always right there to answer my questions and help me protect my horses, my employees and friends, and myself.  Red was a big loss, but I feel so fortunate to have three horses healthy and back in work.
Sources:

1.       Signs of Hendra virus in horses. Available at: http://www.daff.qld.gov.au/4790_20805.htm. Accessed 4/23/13.

2.       Personal protective equipment. Available at: http://www.daff.qld.gov.au/4790_20810.htm. Accessed 4/23/13.

3.       Symptom chart of Proserpine horses. Available at: http://www.hendravirus.org/Documents/Symptom%20chart%20of%20Proserpine%20Horses.pdf. Accessed 4/24/13.

4.       Guidelines for veterinarians handling potential Hendra virus infection in horses. Available at: http://www.daff.qld.gov.au/documents/Biosecurity_GeneralAnimalHealthPestsAndDiseases/Hendra-GuidelinesForVets.pdf. Accessed 4/25/13.

5.       Hendra virus. Available at: http://www.dpi.nsw.gov.au/agriculture/vetmanual/specimens-by-disease-syndrome/diseases_of_livestock/hendra. Accessed 4/25/13.

6.       Hendra diary: John Michell. Available at: http://www.abc.net.au/local/stories/2011/10/11/3336608.htm?site=northcoast. Accessed 4/25/13.

7.       Hendra virus. Available at: http://www.who.int/mediacentre/factsheets/fs329/en/. Accessed 4/27/13.

8.       About me. Available at: http://www.hendravirus.org/aboutme.htm. Accessed 4/27/13.

9.       Reducing the risk of horses becoming infected with Hendra virus. Available at: http://www.daff.qld.gov.au/4790_20806.htm. Accessed 4/27/13.
10.  Overview of Hendra virus – Merck Manual. Available at: http://www.merckmanuals.com/vet/generalized_conditions/ hendra_virus_infection/overview_of_hendra_virus_infection.html. Accessed 4/28/13.