NATALIE Boehm is 24 and feels 50.
She takes 17 tablets a day, can manage only two four-hour shifts a week at work and is so tired some mornings she can barely lift her head off the pillow.
The Brisbane veterinary nurse is one of three known survivors of Hendra virus. Three years after contracting the illness and losing her friend and workmate, vet Ben Cunneen, to it, she is grappling with a debilitating legacy.
“People just can’t understand how this changes you,” she says quietly. “I know I’m lucky to still be here . . . people tell me that all the time. But, to be honest, if I knew how sick I was going to be, I think I would have just rolled over and let it take me.”
Ms Boehm is speaking from the home in Logan City, on Brisbane’s western outskirts, she shares with her parents. The horse country that rolls out towards Beaudesert is on their doorstep and so, too, is the Hendra virus. In nearby Park Ridge, a horse is dead and five properties have been quarantined, as biosecurity agencies scramble to contain the biggest eruption of the bat-borne disease on record.
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Four other horses have died in outbreaks southwest of Brisbane, and 17 people exposed to the virus are undergoing health checks.
In NSW, hit for the first time by dual Hendra emergencies near Lismore and south of Coffs Harbour, another two horses are confirmed dead and 15 people are being monitored.
Among those sweating on blood test results is veterinary surgeon Kylie Schaaf, who tended the dying Park Ridge horse on acreage on Brisbane’s southern suburban fringe.
She worked with Cunneen and Ms Boehm before their encounter with Hendra virus in June 2008. The world of large animal veterinary medicine is a tight one, and this week it reached deep to comfort its own.
Cunneen was the first of two Queensland vets to be killed by Hendra. Ms Schaaf’s travails take to three the number of vets around Brisbane who are waiting anxiously for what everyone hopes will be the all-clear on infection. Another of them, Peter Prenzler, a former One Nation state MP, put down a sick horse on June 20 without knowing it had Hendra.
He was not wearing the personal protection equipment recommended because he thought the dying animal had colic.
“It’s a bit of a cloud hanging over me, but after I got those first tests back and they were clear I felt a lot more confident,” he told The Weekend Australian.
A fourth vet in NSW is in the same predicament, and Ms Boehm says her heart goes out to them all. “I sometimes wish I could go in instead of them because I’ve had the virus,” she says. “I might get sick again, but I can’t catch it again. When I hear there’s another sick horse I feel like saying: ‘Don’t go in there’. I’ve got to live with this, and I can’t stand the thought of anyone else getting sick.”
The events of the past fortnight, with an unprecedented five Hendra flare-ups straddling the Queensland-NSW border, a distance of about 300km, compound the dread invoked by the disease. Never before has it been found as far south as the property at Macksville, 50km out of Coffs Harbour, where a 16-year-old mare was belatedly discovered to have died last Sunday.
And never before have so many outbreaks happened so quickly. “Typically, we see one or two outbreaks a year, and in some cases none at all,” says Queensland chief health officer Jeannette Young.
Chief vet Rick Symons admits this Hendra season is worse in terms of the number of outbreaks, the distribution and the number of people affected. “We have theories, some of them reasonably developed, but very few answers,” Dr Symons says.
Much about the virus remains unknown, including exactly how it is spread by flying foxes to horses, then people, and why it emerges in the chill of the middle months, until now almost exclusively in Queensland. The recorded history of the disease is lamentably short. It was only identified in the spring of 1994 at the Hendra stables of Brisbane horse trainer Vic Rail. He fell ill with a pneumonia-like infection and become the first of its four known human victims.
Soon enough, the fruit bat was pinged as the culprit. The paramyxovirus that it carries is part of the family of viruses that cause measles in people and distemper in dogs. Horses are believed to become infected when they ingest the droppings or bodily secretions of bats feeding or nesting in trees above them. Just why horses are so vulnerable is another of those imponderables. In Malaysia, a close relation of Hendra, the Nipah virus, attacks pigs and can spill across to humans; in Bangladesh, alarmingly, there is no animal bridge: people have been infected directly with Nipah by flying foxes.
Dr Symons says another feature of the current outbreaks is that infected horses are dying faster than before. In some cases, the animal had become sick in the morning and was in such a state by the same afternoon it had to be put down.
Mr Prenzler was horrified by the condition of the horse he encountered on June 20 at Noel Fearon’s Mt Alford property, 80km southwest of Brisbane.
“When we got to the poor horse, it was rolling around in agony,” he says. He did not suspect Hendra at that time. On July 1, he was called back to the property to treat another ill horse. This time, Mr Prenzler donned the PPE gear. The horse had nasal discharge and he thought this was due to spasmodic colic. It was too far gone to help. “It’s bloody awful to watch,” the vet says. “We euthanased the horse.”
Fortunately, Mr Prenzler had the presence of mind to take blood samples from both animals, which later tested positive for Hendra. The pattern has been for horses to present with symptoms not necessarily indicative of the flu-like ones generally associated with the disease.
In the latest confirmed case in Macksville, the animal was unsteady on its legs and disorientated, according to NSW chief vet Ian Roth. It, too, succumbed rapidly. Test results made public on Thursday confirmed the cause was Hendra, and three horses on the property are now being monitored.
Dr Symons says authorities are trying to understand why the virus seems to be more virulent this time around. It could be simply a matter of volume: recent sampling of a colony of bats near Boonah, southwest of Brisbane, found that almost 30 per cent of the animals were carrying active Hendra, against the norm of about 7 per cent.
This goes to another puzzling aspect of the contagion: Hendra typically breaks out in the cool months in Queensland, between May and October. At first, scientists suspected a link to the flying fox’s breeding season.
Now, however, there is growing belief that an array of factors could be involved, including the availability of food for the fruit bats. “It appears there must be a perfect storm of factors, not just the presence of the virus, for spillover (from bats to horses) to occur,” says Hume Field, principal scientist with the Queensland Centre for Emerging Infectious Diseases.
Hendra is lethal when activated. It attacks the lining of small blood vessels, known as arterioles, and nerve cells. The respiratory system and the brain are most vulnerable. Once the virus takes hold, having consolidated in the back of the nose or throat, it enters the blood stream, and symptoms appear.
The lab animals – ferrets – being used by veterinary researcher Deborah Middleton to develop a vaccine and treatment for Hendra generally become ill within three days of exposure.
She says her work at CSIRO’s Geelong-based Australian Animal Health Laboratory is “piggybacking” off research by US scientists, who have been concentrating on Nipah.
This has a somewhat curious antecedent. The Americans have classed Nipah and, by extension Hendra, as a possible biological warfare agent, and their effort to develop a vaccine and antidote has been driven by concern that terrorists could make a weapon of it.
Dr Middleton is particularly interested in what she calls the “stealth period” with Hendra: the time between when the virus starts to replicate and when the victim starts showing symptoms. She found that ferrets that received an antibody treatment derived from the US work on Nipah invariably survived – provided it was administered before they showed signs of illness.
This is the hope of containing Hendra, along with a horse vaccine also being developed by Dr Middleton’s team.
Three people have received the experimental antiserum. It was too late for the last of the four known victims, Rockhampton vet Alister Rodgers, who died in September 2009. Rebecca Day and her daughter, Mollie, 12, of the Sunshine Coast, received the drug last June and emerged with a clean bill of health.
Back in 2008, there was no such help for Ms Boehm. The best Dr Playford and his team could do for her and Mr Cunneen was to treat them with the antiviral Ribavirin, since found to be ineffective against Hendra. Each of them developed acute encephalitis – inflammation of the brain. Dr Cunneen, 33, with a pregnant wife at home, did not come of out an induced coma.
Ms Boehm, for her part, is still fighting her way back from the ordeal. “I have a lot of neurological sort of things that happen,” she says, wearily. “My whole body aches, I have pain, hearing loss in my right ear and this unbelievable fatigue. A couple of weeks ago I turned 24. I felt like I was 50.”
Additional reporting: Andrew Fraser, Sarah Elks