A mosquito bit Emma Shaw on her shoulder in the middle of March this year. From that moment her life plunged into months of misery and pain. Her kids had to miss school for weeks on end because she couldn’t drive them into town. Once supremely fit and a regular 100-lap swimmer, suddenly Emma couldn’t walk, couldn’t get out of bed, couldn’t even lift a cup to her lips.
The mosquito had given Emma a dose of Ross River fever – one of the worst cases her doctor had ever seen. But she says she’s not alone: she knows from her Facebook support group that there are sufferers out there who have been dealing with the crippling effects of this mosquito-borne disease for years.
Last year, mosquitoes infected 6193 Queenslanders with the Ross River virus – one of the worst years on record. Emma was probably bitten by an Aedes camptorynchus or Aedes vigilax mosquito, or it could have been an Culex annulirostris. One tiny bite, by one tiny insect, and healthy, 38-year-old Emma was sick. For months.
Mosquitoes are the world’s worst killers, responsible for more than a million deaths a year worldwide. Carrying the malaria parasite, as well as a huge range of viruses such as dengue, Zika, yellow fever and chikungunya, those irritating specks whining around your head do more damage than tsunamis or earthquakes or wars.
A professional photographer who specialises in portraits, Emma Shaw is one of the mosquito casualties. “I was doing a maternity shoot one afternoon and I was bitten, and within about a week I felt like I had the flu,” she remembers. “I was achy all over, and I had a headache and a really sore throat. Then I woke up one morning and my right ankle, it was just like it was broken. It was severely swollen.
“So I hopped along into the doctor and he realised I had a temperature and all these symptoms, and he thought I had viral arthritis. Then it was in my right knee, my right hip. It just sort of ate its way up my right thigh, in my joints, and then down my left”.
Finally blood tests revealed that Emma had Ross River fever. Emma’s husband is a Fly-In-Fly-Out worker, and usually away. There are six kids in the family, now aged between seven and 19. Emma was bed-bound for a month, so she had to take her kids out of school – the family lives about 25 kilometres from the school, the bus doesn’t go that far, and she simply couldn’t drive them.
Emma had to cancel all her shoots. “I couldn’t even hold my hand up,” she says. “I couldn’t hold a cup of coffee. I had to drink through a straw. The kids had to bring the cup to me”. Finally she took her children home to her extended family in Tasmania to get some help from her relatives.
Now, after eight months of pain and despair, help may finally be at hand. For the past few weeks Emma has been trying a new drug, and she is amazed at the results. “I don’t feel back to normal, but I feel amazing compared with what I was”.
Before she began the trial, she couldn’t squat, or sit on the floor or cross her legs. It felt as though there was grinding in her knees and the cartilage had somehow vanished. But within a couple of weeks of starting the injections, she was back in her doctor’s office, demonstrating her progress by squatting on the floor.
She had battled to be part of this early trial. Like many other GPs in Australia, her doctor was reluctant and had stalled for months. Her husband was dead against it as well, scared by her doctor’s wariness, but Emma was desperate for some relief.
“No-one seems to know much about those of us who get it badly,” she says. “Eighty per cent of people who get it: six weeks and they’re back to being healthy again. The other 20 per cent suffer for far longer. In our support group, some have had it for ten to fifteen years straight, without a day’s break from the symptoms”.
Dr Lara Herrero, an award-winning virologist at Griffith University, recently discovered the novel use of a 50-year-old cystitis drug to treat Ross River virus. She was infected with the virus a decade ago, and it left her with joint pain for two years. It pushed her on her journey to find some sort of cure, or at least symptomatic relief.
“It was hideous,” she says. “It was really hideous. I’ve been a virologist for many years, but I was not an arbovirologist at that time, and I did change my research shortly thereafter”.
She was seeking an anti-inflammatory and anti-viral drug, and with patience and determination she found that injecting patients with pentosan plysulfate sodium (PPS), which had already been approved by the Therapeutic Goods Administration as an oral medication for other ailments, had a beneficial effect.
“We’ve had some really good responses from patients”, she says. “Obviously this is pre-clinical trial work, so it’s a special access scheme. Because there’s no treatment for Ross River, and patients get a bit desperate, they are allowed to access this drug because there’s nothing else available for them, but they have to have a GP to support them”.
Now a clinical trial is in the pipeline, to prove that the drug works to reduce the symptoms of Ross River fever.
So it seems a dedicated scientist may be winning the mosquito war on one front, but the bugs keep biting and people keep getting sick.
In Queensland last year there were 49 cases of malaria recorded (65 so far this year) – nearly all in the Torres Strait. The malaria-carrying Anopheles mosquito doesn’t venture much further south.
But significant numbers of the virus-carrying Aedes aegypti mosquito are found as far south as Charters Towers: and that species can carry dengue fever, and, alarmingly, Zika – the virus that has been linked to microcephaly: babies born with abnormally small heads and malformed brains, or problems with their eyes and ears, or stillborn.
First identified in Uganda in 1947, Zika has spread around the world with surprising speed in recent years. At least 73 countries and territories have reported evidence of mosquito-borne Zika virus transmission since 2007, and last year the disease erupted in South America. In October 2015, Brazil reported a connection between Zika and microcephaly. More than 3000 microcephaly cases have been confirmed in Brazil alone.
Even babies born with normally-sized heads to Zika-affected mothers may suffer from future complications. Earlier this year, it was reported that Brazilian babies who at first seem to have escaped Zika-connected microcephaly, and whose heads were of normal size, were found to have delayed neuro-development.
In September, Thailand reported the first confirmed cases of microcephaly connected to Zika in south-east Asia, a day after US health authorities warned pregnant women to postpone non-essential travel to 11 south-east Asian nations. It’s likely that Zika has taken firm hold in many of these nations, and even in parts of Florida, in the US, but no-one wants to scare away the tourists.
So far there have been no locally caught cases of Zika in Queensland. All 37 cases recorded this year were caught in other countries; in Thailand or the Philippines or Fiji, amongst others. Yet health experts are deeply concerned the virus could take hold and spread – via the Aedes aegypti mosquitoes.
Annabel Bailey (not her real name), a medical student from North Queensland, visited Fiji earlier this year. And caught Zika.
“I must have (been bitten), I tried really hard not to be, applying repellent pretty regularly, but somehow they still got me,” she says. “I felt like I’d been hit by a bus for a day. I was really lethargic; aches-and-painsy. I think I had a fever, but I didn’t have anything to measure it with. It was just for one day. Then I had a rash from head to toe for the following two days. And that was it. I assumed it was a bit of a viral rash”.
When she got back to Australia she was simply tired. Her GP sent a sample of her blood off to be tested, and the tests found she had Zika. Luckily Annabel hadn’t yet gone home to North Queensland so it wasn’t possible for a mosquito to carry the disease from her to another person. And luckily she wasn’t pregnant, so there was no chance of a child of hers being affected by microcephaly. When she did get back to North Queensland, the health authorities sprayed her home with insecticide and mosquito traps were set up in the area, just in case.
“I know it’s a very mild illness, and it doesn’t affect me, at all”, she says. “I am curious because it’s still being investigated … they don’t know all the effects of it. So I’m keeping my ear to the ground, that’s for sure”.
The now widely-accepted idea that the Zika virus causes neurological complications in babies, even those born with normally-sized heads, has prompted the scientific world to consider the links that might exist between other viruses and various ailments.
Dr Andrew Taylor-Robinson, a professor of immunology at Central Queensland University, has sounded a warning. “We have a massive knowledge gap”, he tells QWeekend. “We have viruses that cause feverish illnesses, and we’re aware of that, but it’s a case of ‘you might be crook for two or three days, so you take some time off work, you have mild flu-like symptoms’. I think that (mild fever) might be the tip of the iceberg”.
There may be significant health problems that have simply not yet been linked to exposure to a virus, he adds. The problems might be neurological, or they could be ailments of some other kind.
“It wouldn’t surprise me if there was a connection with a neurological manifestation. Something like this (a viral infection) might just be a trigger. A lot of the things you see like this are auto-immune disorders”.
Dr Taylor-Robinson fears that more than half of Queenslanders turning up at doctor’s surgeries with a mild fever have their ailment either undiagnosed or misdiagnosed, and it’s likely the patient’s blood wouldn’t be tested for viral infections. At least 70 known viruses float around in the Australian bush, along with about 80 different species of mosquitoes, he adds.
Some of the viruses are well-known, such as Ross River virus and Murray Valley encephalitis, but most of them have never even been named. “We actually don’t know a huge amount about those,” he says. Diagnostic tests have yet to be developed for these viruses, and it’s not yet known whether any of them trigger auto-immune complications.
Still, unlike the bush mosquitoes that spread Ross River virus and Barmah Forest and rampage through much of Queensland, the exotic dengue and Zika-carrying Aedes aegypti can be controlled by spraying the interior of houses, with mosquito traps and finally, with bacteria. An Australian program is using a specific type of bacteria to gradually win the war with this little beast that carries a range of deadly and debilitating diseases.
In a world-first, several years ago Australian scientists discovered that certain strains of Wolbachia bacteria have valuable disease-blocking properties. Already common in many species of insect, the naturally-occurring Wolbachia bacteria prevent mosquitoes transmitting dengue and, it was recently confirmed, Zika, in the Aedes aegypti mosquito: a comforting thought for the people of North Queensland.
Adult mosquitoes carrying Wolbachia have been released in a number of trial sites by the Monash University-based ‘Eliminate Dengue’ program since 2011, first in Queensland and then internationally. The carefully-bred Wolbachia mosquitoes mate with wild local mosquitoes and the subsequent mosquito offspring inherit Wolbachia, creating a self-sustaining population of mosquitoes that cannot transmit the dengue or Zika viruses.
The mosquito populations of the trial site are then regularly tested to assess how well Wolbachia is infiltrating the mosquito population, and consequently blocking disease transmission.
So far the Australian trials have been a resounding success. Not one person has caught dengue in a Wolbachia trial area in North Queensland. Numbers of locally-acquired cases over the whole of Queensland have fallen – from 222 in 2013, to 34 so far this year.
The Wolbachia trials have been working well in Indonesia and Vietnam, and more recently in Colombia and Brazil, where Zika and dengue wreak such havoc.
Still, dengue is a worldwide scourge. Widespread in the tropics, with the World Health Organisation noting there were perhaps as many as 390 million cases globally last year, dengue killed as many as 1181 people in the Americas alone in 2015.
The world is sitting up and taking notice. Recently the non-profit Eliminate Dengue program, led by Professor Scott O’Neill, was given US$18 million by global donors, including the Bill and Melinda Gates Foundation, to run huge Wolbachia trials in Brazil and Colombia.
There are four types of the dengue virus. People become immune to a particular type of dengue virus once they’ve had it, but can still get catch one of the other types and, even if it’s years later, getting a second bout of dengue increases the risk of developing severe dengue. Severe dengue causes bleeding and shock, and has killed Queenslanders in the past.
Gift shop-owner Diana Lynch is on an Eliminate Dengue community committee in Charters Towers. Like so many others in North Queensland, she is a huge supporter of the program: she had dengue in 1993, when she was pregnant, and she says it nearly killed her.
“We had a really big epidemic in town at the time,” she remembers. “My husband at the time also had it, and I was 16 weeks pregnant with my second child. It came as close to killing me as I think anything could. I was so ill”.
She ended up on a drip, and lost the baby, but she insists the dengue didn’t affect her pregnancy – the child was still-born for other reasons. Whatever the case, she went through a few months of hell.
“Half the town still says, ‘I don’t care what they say, it must have been that dengue (that caused the loss of the baby)’,” she remembers. “It was a bad time. I had a very active two-year-old who learned how to run the video and things, so I could lie on the lounge dying while he could turn it on and rewind it”.
As a shop-owner, Diana gets to chat to a lot of people in Charters Towers, and she has monitored the local community’s response to the Eliminate Dengue program. Originally it was thought that some people in the town might object to the very idea of releasing yet more mosquitoes, but that hasn’t happened. “I haven’t had a single bad bit of feedback,” she says. “Everybody I see is really happy it’s happening, who wouldn’t be? And Zika’s the real bonus”.
She applauds the plans for releasing Wolbachia mosquitoes in other nations. “It’s amazing,” she says. “It could change the world, as far as sorting out Zika and dengue”.
The Queensland government has provided research grants of about $3 million to support the Eliminate Dengue program in North Queensland, but some have asked why money has not been forthcoming to fund a rollout of Wolbachia mosquitoes across all those places where Aedes aegypti can be found.
In the past, Aedes aegypti – an urban insect that can breed in an upturned bottle-top – was found right across Queensland, in parts of the Northern Territory and northern NSW.
Experts warn there’s a chance the species could spread south from North Queensland, particularly if it can find the right places to breed, and the current trend of installing water tanks is causing some concern. Although new tanks have protective screens, they’re plastic, and plastic perishes over time.
Dengue and Zika can also be carried by the notorious Asian Tiger mosquito, or Aedes albopictus, but so far that species is only found in the Torres Strait and there is an intensive program underway to prevent the insects migrating any further south. Yet Queensland Health says there is a “significant risk” that sooner or later these Tiger mosquitos will spread to the Queensland mainland.
Dr Steven Donohue, director of the Tropical Public Health Unit in Townsville, says at the moment North Queensland is one of the few places in the world where dengue outbreaks can be found and eliminated before they spread too far. A first world health system, an educated public and recourse to mosquito controls such as insecticides and larvicides mean that the battle against spotfire dengue oubreaks can be won.
But Zika is different. In many cases, people who have Zika are asymptomatic – they don’t feel ill and they probably don’t even know they are carrying the disease that can be so devastating for unborn babies. And as well as being carried by mosquitoes, it seems that Zika can be spread by sexual contact.
“If Zika starts in Queensland, it’s more likely to be in the small towns where we haven’t got the Eliminate Dengue program at the moment,” Dr Donohue says. “The success in previous years with dengue has lulled us into a false sense of security. But if you don’t know where the cases are, you can’t do the same thing as you do with dengue”.
Health authorities in Townsville are now doing a lot of testing to establish whether this silent transmission is already occurring: any blood that is tested for dengue, or Ross River or Barmah Forest virus, is automatically also tested for Zika.
“If it does get established here, it could be very, very difficult, not only to get rid of, but also we wouldn’t know what to tell people,” he says. “Let’s say there was a proven case of Zika in Innisfail, and the person hasn’t travelled (overseas). We’d declare an outbreak, but we’d have to tell the public, well, honestly, we don’t know how many cases there are, we don’t know exactly where they are, and we don’t know how long it’s going to last”.
The Eliminate Dengue program’s Wolbachia mosquitos are saving the day in North Queensland’s bigger towns, but there are still a few towns, and a few suburbs, where the rollout has yet to begin, and where Zika and dengue could take hold. “By the end of the year”, Dr Donohue says, “we expect to have all of Cairns, all of Townsville, all of Charters Towers and all of Port Douglas protected (by Wolbachia mosquitoes), and that includes Mossman and some places close to Cairns.
“The places that are yet to be protected include places like Innisfail, Ingham, Tully, Mission Beach, and El Arish, not to mention the Torres Strait. We’re still vulnerable, and that’s a pity”.