Climate Q&A: will we be less healthy because of climate change?



Climate change, together with other ecological pressures, may well undo the gains we have made in health.
from http://www.shutterstock.com, CC BY-ND

Alexandra Macmillan, University of Otago

Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change. If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz

Do you expect an increase in health issues due to the effects of climate change? – a question from Christine in Wellington

Some of the negative health effects of climate change are already upon us, but it’s not all doom and gloom. There is a huge opportunity for better health through well designed action to reduce our emissions and by adapting to the changes we are facing.

You may already be experiencing one of the potential impacts of climate change on our mental health. In recent years, the New Zealand Psychological Society has reported seeing some cases of anxiety, helplessness and depression about climate change. This is most evident when individual concerns are expressed collectively in the form of protest such as the school strikes for climate. Thousands of young people around New Zealand – and reportedly more than a million globally – have been striking to express their fears about the future.




Read more:
Climate change: seeing the planet break down is depressing – here’s how to turn your pain into action


The grief and depression that can result from the destruction of places and landscapes people love led Australian environmental philosopher Glenn Albrecht to create a new word: “solastalgia”.

Global warnings

In New Zealand, the past half century has seen ongoing improvements in the health of the overall population, with an expectation that our children will have better health, life expectancy and quality of life than their parents.

But as a number of reports have found, including medical journal The Lancet’s Countdown 2018 report, climate change may well undo these health gains in tandem with other ecological pressures we have created. Global measures of health mask unequal gains between populations and groups between and within countries. Climate change will make these health inequalities worse.

The pathways between climate change and human health, from a global report on climate change and health.
2018 report of the Lancet Countdown on health and climate change, CC BY-NC-ND

The Lancet’s report warns that “the nature and scale of the response to climate change will be the determining factor in shaping the health of nations for centuries to come”.

Climate change and health in New Zealand

In New Zealand, warmer winters may reduce the number of people who die (currently about 1600 each year), mostly from heart and lung disease. But unfortunately, the overall impact will be negative on a wide range of other causes of illness and mortality. It is likely that climate change will bring diseases unfamiliar in New Zealand (especially infectious diseases, such as dengue fever), but more importantly, climate change amplifies chronic and infectious diseases we already suffer from, such as the impacts of heat on heart disease, and changing rainfall patterns on waterborne illnesses.

One major direct impact on health was made evident by the huge outbreak of campylobacter, a bacterial infection that causes gastroenteritis, in Havelock North during the winter of 2016. Some 5,500 people in a town of 14,000 residents became unwell, with 45 people hospitalised. A government inquiry attributed the outbreak to a combination of extreme rainfall that washed sheep faeces into a pond near a water bore and poor drinking water management. The outbreak may even have contributed to three people’s deaths.

Warming of freshwater and more extreme rainfall events are both part of climate change, increasing the likelihood of outbreaks like the one in Havelock North.

Indirect effects on health will be as important, but they are more difficult to measure and predict. Climate change undermines many of the building blocks of good health: clean air, plentiful safe drinking water, affordable healthy food, affordable dry houses, and economic stability and peace. The threat to food security and therefore nutrition is just one worrying example.




Read more:
How climate change affects the building blocks for health


Changing seasonal temperatures and weather extremes are already reducing harvests of important staples like wheat, while warming oceans are reducing our ability to harvest fish and shellfish. Both are staples in New Zealand’s diet. We already have a problem with many families not being able to afford to always put a meal on the table, let alone a healthy one. When this worsens, the result is, perversely, an increase in obesity and diabetes, accompanied by nutrient deficiencies, as families rely on cheap, highly processed foods to get by.

Overall, many New Zealanders are experiencing better health than in the past, but we have persistent health inequalities as a result of multiple structural injustices, including poverty. People on low incomes, Māori and Pasifika, the elderly and children will be worst affected by climate change, but wealth and white privilege do not confer immunity.

The overwhelmingly negative effects of climate change on health are a strong argument for urgent action to reduce our climate pollution.

But well designed action also offers opportunities to address New Zealand’s biggest causes of death and disease: cancer, heart disease, diabetes and obesity. For example, if we reduce our transport emissions by improving access to safe walking and cycling routes and electric public transport, air quality will improve and we build physical exercise back into our daily lives. Shifting our farming sector from a heavy focus on producing milk powder towards plant-based food production would not only change our national diets for the better, but also ensure we are resilient to global food price shocks and improve our fresh and drinking water.

Our health system will need significant strengthening if we are to be in a good position to weather the coming climate disruptions. This is particularly so in public health, which sets up systems for dealing with outbreaks and emergencies. We also know from our experiences of past major calamities such as earthquakes, that the resilience that comes from strong communities is a huge advantage. Taking co-ordinated action together can be crucial for health during upheaval.The Conversation

Alexandra Macmillan, Senior Lecturer in environmental sustainability and public health and co-convenor of OraTaiao: NZ Climate & Health Council, University of Otago

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Advertisements

Increasing tree cover may be like a ‘superfood’ for community mental health



Imagine Hyde Park in Sydney without its tree cover … the impact on this space and the many people who spend time in it would be profound.
EA Given/Shutterstock

Thomas Astell-Burt, University of Wollongong and Xiaoqi Feng, University of Wollongong

Increasing tree canopy and green cover across Greater Sydney and increasing the proportion of homes in urban areas within 10 minutes’ walk of quality green, open and public space are among the New South Wales premier’s new priorities. Cities around Australia have similar goals. In our latest study, we asked if more of any green space will do? Or does the type of green space matter for our mental health?

Our results suggest the type of green space does matter. Adults with 30% or more of their neighbourhood covered in some form of tree canopy had 31% lower odds of developing psychological distress. The same amount of tree cover was linked to 33% lower odds of developing fair to poor general health.

We also found poorer mental and general health among adults in areas with higher percentages of bare grass nearby, but there’s likely more to that than meets the eye.




Read more:
Green for wellbeing – science tells us how to design urban spaces that heal us


Treed neighbourhoods have a natural appeal to people.
Tim Gouw/Unsplash

How did we do the research?

Our research involved tracking changes in health over an average of about six years, for around 46,000 adults aged 45 years or older, living in Sydney, Newcastle or Wollongong. We examined health in relation to different types of green space available within a 1.6 kilometre (1 mile) walk from home.

Our method helped to guard against competing explanations for our results, such as differences in income, education, relationship status, sex, and age. We also restricted the sample to adults who did not move home, because it is plausible that people who are already healthier (for instance because they are more physically active) move into areas with more green space.

So is the answer simply more trees and less grass? Not exactly. Let’s get into the weeds.




Read more:
Green space – how much is enough, and what’s the best way to deliver it?


Trees make it cool to walk

Imagine you’re walking down a typical street on a summer’s day in the middle of an Australian city. It’s full of right angles, grey or dark hard surfaces, glass structures, and innumerable advertisements competing for your attention. Then you turn a corner and your gaze is drawn upwards to a majestic tree canopy exploding with a vivid array of greens for as far as you can see.

A tree-lined street like Swanston Street in Melbourne is a more walkable street.
kittis/Shutterstock

Let’s get the obvious out of the way. Walking down this green street, you may instantly feel some relief from the summer heat.

Studies are linking high temperatures with heat exhaustion and mental health impacts. Research has suggested trees, rather than other forms of green space, may be best at reducing temperatures in cities. It may also simply be more comfortable to walk outside in cooler temperatures – not to mention going for a run or bike ride, both of which are good for mental health.




Read more:
Our cities need more trees, but some commonly planted ones won’t survive climate change


Feeling restored and alert

But as the minutes of walking beneath this natural umbrella of lush foliage accumulate, other things are happening too. The vibrant colours, natural shapes and textures, fresh aromas, and rustling of leaves in the breeze all provide you with effortless distraction and relief from whatever it was you might have been thinking about, or even stressing over.

Trees can provide a soothing sensory distraction from our troubles.
Jake Ingle/Unsplash

Studies back this up. Walks through green space have been shown to reduce blood pressure, improve mental acuity, boost memory recall, and reduce feelings of anxiety. The Japanese have a name for this type of experience: shinrin-yoku.

Friends, old and new

You walk past groups of people on the footpath taking time to catch up over coffee in the shade. Some research has found that tree cover, rather than green space more generally, is a predictor of social capital. Social capital, according to Robert Putnam, refers to the “social networks and the associated norms of reciprocity and trustworthiness” that may have important influences on our life chances and health.

Dogs and trees both contribute to building healthy social relations.
Liubov Ilchuk/Unsplash

You walk further and a chorus of birdsong soars through the neighbourhood noise. Trees provide shelter and food for a variety of animals. Research suggests tree canopy tends to be more biodiverse than low-lying vegetation.

Increased biodiversity may support better mental health by enhancing the restorative experience and also via the immunoregulatory benefits of microbial “Old Friends” – microorganisms that helped shape our immune systems but which have been largely eliminated from our urban environments.

Green spaces with tree canopy are settings where communities can come together to watch birds and other animals, which can also be catalysts for new conversations and developing feelings of community belonging in the neighbourhoods where we live … just ask dog owners.




Read more:
Reducing stress at work is a walk in the park


So, what about the grass?

Our research did not show a mental health benefit from more bare grassed areas. This does not mean grass is bad for mental health.

Previous research suggests adults are less likely to wander in green spaces that are relatively plain and lacking in a variety of features or amenities.
This may also be partly attributable to preferences for green spaces with more complex vegetation, such as parks that mix grass with tree canopy.

Parks with a variety of vegetation, including trees and grass, may be more attractive for a wider range of outdoor activities than those with few trees.
Author

Furthermore, large areas of bare grass in cities can make built environments more spread-out and less dense. Without tree canopy to shield from the midday sun, this may increase the likelihood of people using cars for short trips instead of walking through a park or along a footpath. The result is missed opportunities for physical activity, mental restoration, and impromptu chats with neighbours. Previous work in the United States suggests this might be why higher death rates were found in greener American cities.

Grassed areas can occupy a large amount of space for surprisingly little mental health benefit.
chuttersnap/Unsplash

Large open areas of grass can be awesome for physical activity and sport, but let’s make sure there is also plenty of tree canopy too, while also thinking about ways to get more people outdoors in green spaces. Here are some suggestions.

Making Australia greener and healthier

As the density of Australian cities continues to increase and more of us live in apartments and/or work in high-rise office blocks, it is great to see strategies to invest in tree cover and urban greening more generally across Australia. Cities with such plans include Sydney, Melbourne, Brisbane, Bendigo, Fremantle, and Wollongong.

You can get involved and have some fun at the same time too. Lots of evidence says gardening is really great for your mental health. So why not grab a mate and spend a couple of hours planting a tree on July 28 for National Tree Day!The Conversation

Both the act of planting a tree and its presence over the decades are good for us.
Amy Fry/flickr, CC BY-NC-SA

Thomas Astell-Burt, Professor of Population Health and Environmental Data Science, NHMRC Boosting Dementia Research Leadership Fellow, University of Wollongong and Xiaoqi Feng, Associate Professor of Epidemiology and NHMRC Career Development Fellow, University of Wollongong

This article is republished from The Conversation under a Creative Commons license. Read the original article.

We know contact with nature makes you feel better. Can virtual contact do the same?



There is a link between exposure to natural settings and better psychological well-being.
Shutterstock

Navjot Bhullar, University of New England

You might have noticed that being in nature can improve your mood. Whether it’s walking in a beautiful rainforest, swimming in the ocean or a moment of wonder at the plants and animals around you, nature offers a respite from daily routines and demands.

In 1984, the sociobiologist Edward O. Wilson described this innate desire to connect with natural environments – and the positive experiences we derive from this connection – as the “biophilia hypothesis”:

Biophilia, if it exists, and I believe it exists, is the innately emotional affiliation of human beings to other living organisms.

There is evidence to back up the link between exposure to natural settings and better psychological well-being.

And my own research suggests that virtual exposure to nature via film (videos) or virtual reality can mimic this effect.




Read more:
Why a walk in the woods really does help your body and your soul


Why being in nature makes us feel better

Studies on the psychological benefits of exposure to nature show spending time in natural settings can result in:

Two major theories help us understand how exposure to nature increases mood and psychological well-being.

First, Attention Restoration Theory is the idea that natural environments restore attention. We can only focus our attention for a certain period of time before feeling mentally fatigued. A short break in natural environments helps restore it.

This sense of “restorativeness” improves our sense of well-being, and breaks the routine of our every day life. Restorativeness explains some of the association between nature experience and psychological well-being.

Then there is Stress Reduction Theory. This suggests that natural environments promote recovery from stress, which is different from attention fatigue.

Non-threatening, natural environments would have increased the chances of survival for our ancestors because they provided opportunities for reproduction, food and shelter. As a result, we’ve evolved to respond positively to such settings.

Emotional responses to aesthetically pleasing stimuli, such as green spaces, also tend to decrease physiological arousal, thus making us feel relaxed.




Read more:
Virtual reality adds to tourism through touch, smell and real people’s experiences


Virtual contact with nature mimics this effect

In a meta-analysis of 32 studies, researchers compared the effects of exposure to both natural and urban environments. Results showed that exposure to natural environments showed a moderate association with higher positive mood.

This exposure doesn’t have to take place in-person. Research I conducted with my colleagues at the University of New England’s Applied Psychology Lab showed that while people got the most psychological benefit from physical exposure to nature, exposure to simulated natural environments – such as film or virtual reality – had a comparable effect.

One study showed that taking part in a virtual reality experience of a natural environment resulted in higher levels of positive affect and greater attention restoration compared to a virtual reality experience of an urban environment.

Psychological benefits seem to be dependent on the type of nature experience. Another study found that a virtual experience of wild nature (defined as natural settings, such as wilderness with little human interference) improved positive mood. By contrast, a virtual experience of urban nature (such as parks in urbanised areas) exerted its beneficial effect by reducing negative mood.

The studies also showed that simulated natural environments providing realistic representations of nature, such as interactive virtual reality, resulted in greater psychological benefits than less immersive mediums such as photographs of natural settings.




Read more:
Inspired, magical, connected: How virtual reality can make you well


Increasing our daily contact with nature

In a modern world increasingly characterised by built environments, it’s not always possible to spend time in nature every day. Promoting exposure to virtual natural environments seems like an effective way of improving psychological well-being.

Simulated representations of nature can help improve urban and indoor environments where access to nature is limited, such as hospitals, urban offices, apartments, and inner city schools.

That might mean displaying photographs and moving videos of natural colours and patterns, installing living green walls, or placing potted plants in areas people move through everyday.The Conversation

Navjot Bhullar, Associate Professor – Faculty of Medicine and Health; School of Psychology, University of New England

This article is republished from The Conversation under a Creative Commons license. Read the original article.

After decades away, dengue returns to central Queensland



Australia’s dengue cases are usually limited to far north Queensland.
Shutterstock

Cameron Webb, University of Sydney

The Queensland city of Rockhampton was free of dengue for decades. Now, a case of one of the most serious mosquito-borne diseases has authorities scratching their heads.

Over the past decade, dengue infections have tended to be isolated events in which international travellers have returned home with the disease. But the recent case seems to have been locally acquired, raising concerns that there could be more infected mosquitoes in the central Queensland town, or that other people may have been exposed to the bites of an infected mosquito.

What is dengue fever?

The illness known as dengue fever typically includes symptoms such as rash, fever, headache, joint pain, vomiting, diarrhoea, and abdominal pain. Symptoms can last for around a week or so. Four types of dengue virus cause the illness and they are spread by mosquito bites.

Once infected, people become immune to that specific dengue virus. However, they can still get sick from the other dengue viruses. Being infected by multiple dengue viruses can increase the risk of more severe symptoms, and even death.

Hundreds of millions of people are infected each year. It is estimated that 40% of the world’s population is at risk given the regions where the virus, and the mosquitoes that spread it, are active. This includes parts of Australia.




Read more:
Explainer: what are antibodies and why are viruses like dengue worse the second time?


The last significant outbreak in Australia occurred in far north Queensland in 2009, when more than 900 people were infected by local mosquitoes.

Only a handful of locally acquired cases have been reported around Cairns and Townsville in the past decade. All these cases have two things in common: the arrival of infected travellers and the presence of the “right” mosquitoes.

The dengue virus isn’t spread from person to person. A mosquito needs to bite an infected person, become infected, and then it may transmit the virus to a second person as they bite. If more people are infected, more mosquitoes can pick up the virus as they bite and, subsequently, the outbreak can spread further.

Why are mosquitoes important?

Australia has hundreds of different types of mosquitoes. Dozens can spread local pathogens, such as Ross River virus, but just one is capable of spreading exotic viruses such as dengue and Zika: Aedes aegypti.

Aedes aegypti breeds in water-holding containers around the home. It is one of the most invasive mosquitoes globally and is easily moved about by people through international travel. While these days the mosquito stows away in planes, historically it was just as readily moved about in water-filled barrels on sailing ships.

Aedes aegypti is the mosquito primarily responsible for the spread of dengue viruses.
By James Gathany – PHIL, CDC, Public Domain

The spread of Aedes aegypti through Australia is the driving force in determining the nation’s future outbreak risk.

The mosquito was once widespread in coastal Australia but since the 1950s, it become limited to central and far north Queensland. We don’t really know why – there are many possible reasons for the retreat, but the important thing now is they don’t return to temperate regions of the country.

Authorities must be vigilant to monitor their spread and, where they’re currently found, building capacity to respond should cases of dengue be identified.




Read more:
Is climate change to blame for outbreaks of mosquito-borne disease?


What happened in Rockhampton?

Last week, for the first time in decades, a locally acquired case of dengue was detected in Rockhampton, in central Queensland. The disease was found in someone who hasn’t travelled outside the region, which suggests they’ve been bitten locally by an infected mosquito.

This has prompted a full outbreak response to protect the community from any additional infected mosquitoes.

While the risk of dengue around central Queensland is considered lower than around Cairns or Townsville, authorities are well prepared to respond, with a variety of techniques including house-to-house mosquito surveillance and mosquito control to minimise the spread.

These approaches have been successful around Cairns and Townsville for many years and have helped avoid substantial outbreaks.

The coordinated response of local authorities, combined with the onset of cooler weather that will slow down mosquitoes, greatly reduces any risk of more cases occurring.

What can we do about dengue in the future?

Outbreaks of dengue remain a risk in areas with Aedes aegypti mosquitoes. There are also other mosquitoes, such as Aedes albopictus (the Asian tiger mosquito), that aren’t currently found on mainland Australia but may further increase risks should they arrive. Authorities need to be prepared to respond to the introductions of these mosquitoes.




Read more:
How we kept disease-spreading Asian Tiger mozzies away from the Australian mainland


While a changing climate may play a role in increasing the risk, increasing international travel, which represents pathways of introduction of “dengue mosquitoes” into new regions of Australia, may be of greater concern.

There is more that can be done, both locally and internationally. Researchers are working to develop a vaccine that protects against all four strains of dengue virus.

Others are tackling the mosquitoes themselves. Australian scientists have played a crucial role in using the Wolbachia bacteria, which spreads among Aedes aegypti and blocks transmission of dengue, to control the disease.

The objective is to raise the prevalence of the Wolbachia infections among local mosquitoes to a level that greatly reduces the likelihood of local dengue transmission.

Field studies have been successful in far north Queensland and may explain why so few local cases of dengue have been reported in recent years.

While future strategies may rely on emerging technologies and vaccines, simple measures such as minimising water-filled containers around our homes will reduce the number of mosquitoes and their potential to transmit disease.The Conversation

Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Expanding gas mining threatens our climate, water and health


Melissa Haswell, Queensland University of Technology and David Shearman, University of Adelaide

Australia, like its competitors Qatar, Canada and the United States, aspires to become the world’s largest exporter of gas, arguing this helps importing nations reduce their greenhouse emissions by replacing coal.

Yes, burning gas emits less carbon dioxide than burning coal. Yet the “fugitive emissions” – the methane that escapes, often unmeasured, during production, distribution and combustion of gas – is a much more potent short-term greenhouse gas than carbon dioxide.




Read more:
Who gets to decide whether we dig up coal and gas?


A special report issued by the World Health Organisation after the 2018 Katowice climate summit urged governments to take “specific commitments to reduce emissions of short-lived climate pollutants” such as methane, so as to boost the chances of staying with the Paris Agreement’s ambitious 1.5℃ global warming limit.

Current gas expansion plans in Western Australia, the Northern Territory and Queensland, where another 2,500 coal seam gas wells have been approved, reveal little impetus to deliver on this. Harvesting all of WA’s gas reserves would emit about 4.4 times more carbon dioxide equivalent than Australia’s total domestic energy-related emissions budget.

Gas as a cause of local ill-health

There are not only global, but also significant local and regional risks to health and well-being associated with unconventional gas mining. Our comprehensive review examines the current state of the evidence.

Since our previous reviews (see here, here and here), more than 1,400 further peer-reviewed articles have been published, helping to clarify how expanding unconventional gas production across Australia risks our health, well-being, climate, water and food security.




Read more:
Chief Scientist CSG report leaves health concerns unanswered


This research has been possible because, since 2010, 17.6 million US citizens’ homes have been within a mile (1.6km) of gas wells and fracking operations. Furthermore, some US research funding is independent of the gas industry, whereas much of Australia’s comparatively small budget for research in this area is channelled through an industry-funded CSIRO research hub.

Key medical findings

There is evidence that living close to unconventional gas mining activities is linked to a wide range of health conditions, including psychological and social problems.

The US literature now consistently reports higher frequencies of low birth weight, extreme premature births, higher-risk pregnancies and some birth defects, in pregnancies spent closer to unconventional gas mining activities, compared with pregnancies further away. No parallel studies have so far been published in Australia.

US studies have found increased indicators of cardiovascular disease, higher rates of sinus disorders, fatigue and migraines, and hospitalisations for asthma, heart, neurological, kidney and urinary tract conditions, and childhood blood cancer near shale gas operations.

Exploratory studies in Queensland found higher rates of hospitalisation for circulatory, immune system and respiratory disorders in children and adults in the Darling Downs region where coal seam gas mining is concentrated.

Water exposure

Chemicals found in gas mining wastewater include volatile organic compounds such as benzene, phenols and polyaromatic hydrocarbons, as well as heavy metals, radioactive materials, and endocrine-disrupting substances – compounds that can affect the body’s hormones.

This wastewater can find its way into aquifers and surface water through spillage, injection procedures, and leakage from wastewater ponds.

The environmental safety of treated wastewater and the vast quantities of crystalline salt produced is unclear, raising questions about cumulative long-term impacts on soil productivity and drinking water security.

Concern about the unconventional gas industry’s use of large quantities of water has increased since 2013. Particularly relevant to Australian agriculture and remote communities is research showing an unexpected but consistent increase in the “water footprint” of gas wells across all six major shale oil and gas mining regions of the US from 2011 to 2016. Maximum increases in water use per well (7.7-fold higher, Permian deposits, New Mexico and Texas) and wastewater production per well (14-fold, Eagle Ford deposits, Texas) occurred where water stress is very high. The drop in water efficiency was tied to a drop in gas prices.

Air exposure

Research on the potentially harmful substances emitted into the atmosphere during water removal, gas production and processing, wastewater handling and transport has expanded. These substances include fine particulate pollutants, ground-level ozone, volatile organic compounds, polycyclic aromatic hydrocarbons, hydrogen sulfide, formaldehyde, diesel exhaust and endocrine-disrupting chemicals.

Measuring concentrations and human exposures to these pollutants is complicated, as they vary widely and unpredictably in both time and location. This makes it difficult to prove a definitive causal link to human health impacts, despite the mounting circumstantial evidence.




Read more:
Why Australians need a national environment protection agency to safeguard their health


Our review found substantially more evidence of what we suspected in 2013: that gas mining poses significant threats to the global climate, to food and water supplies, and to health and well-being.

On this basis, Doctors for the Environment Australia (DEA) has reinforced its position that no new gas developments should occur in Australia, and that governments should increase monitoring, regulation and management of existing wells and gas production and transport infrastructure.The Conversation

Melissa Haswell, Professor of Health, Safety and Environment, School of Public Health and Social Work, Queensland University of Technology, Queensland University of Technology and David Shearman, Emeritus Professor of Medicine, University of Adelaide

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Explainer: what is Murray Valley encephalitis virus?


Ana Ramírez, James Cook University; Andrew Francis van den Hurk, The University of Queensland; Cameron Webb, University of Sydney, and Scott Ritchie, James Cook University

Western Australian health authorities recently issued warnings about Murray Valley encephalitis, a serious disease that can spread by the bite of an infected mosquito and cause inflammation of the brain.

Thankfully, no human cases have been reported this wet season. The virus that causes the disease was detected in chickens in the Kimberley region. These “sentinel chickens” act as an early warning system for potential disease outbreaks.

What is Murray Valley encephalitis virus?

Murray Valley encephalitis virus is named after the Murray Valley in southeastern Australia. The virus was first isolated from patients who died from encephalitis during an outbreak there in 1951.

The virus is a member of the Flavivirus family and is closely related to Japanese encephalitis virus, a major cause of encephalitis in Asia.

Murray Valley encephalitis virus is found in northern Australia circulating between mosquitoes, especially Culex annulirostris, and water birds. Occasionally the virus spreads to southern regions, as mosquitoes come into contact with infected birds that have migrated from northern regions.




Read more:
After the floods come the mosquitoes – but the disease risk is more difficult to predict


How serious is the illness?

After being transmitted by an infected mosquito, the virus incubates for around two weeks.

Most people infected don’t develop symptoms. But, if you’re unlucky, you could develop symptoms ranging from fever and headache to paralysis, encephalitis and coma.

Around 40% of people who develop symptoms won’t fully recover and about 25% die. Generally, one or two human cases are reported in Australia per year.

Since the 1950s, there have been sporadic outbreaks of Murray Valley encephalitis, most notably in 1974 and 2011. The 1974 outbreak was Australia-wide, resulting in 58 cases and 12 deaths.

It’s likely the virus has been causing disease since at least the early 1900s when epidemics of encephalitis were attributed to a mysterious illness called Australian X disease.

Traditional monitoring of mosquito-borne diseases relies on the collection of mosquitoes using specially designed traps baited with carbon dioxide.
Cameron Webb

Early warning system

Given the severity of Murray Valley encephalitis, health authorities rely on early warning systems to guide their responses.

One of the most valuable surveillance tools to date have been chooks because the virus circulates between birds and mosquitoes. Flocks of chickens are placed in areas with past evidence of virus circulation and where mosquitoes are buzzing about.

Chickens are highly susceptible to infection so blood samples are routinely taken and analysed to determine evidence of virus infection. If a chicken tests positive, the virus has been active in an area.

The good news is that even if the chickens have been bitten, they don’t get sick.

Mosquitoes can also be collected in the field using a variety of traps. Captured mosquitoes are counted, grouped by species and tested to see if they’re carrying the virus.

This method is very sensitive: it can identify as little as one infected mosquito in a group of 1,000. But processing is labour-intensive.




Read more:
How Australian wildlife spread and suppress Ross River virus


How can technology help track the virus?

Novel approaches are allowing scientists to more effectively detect viruses in mosquito populations.

Mosquitoes feed on more than just blood. They also need a sugar fix from time to time, usually plant nectar. When they feed on sugary substances, they eject small amounts of virus in their saliva.

This led researchers to develop traps that contain special cards coated in honey. When the mosquitoes feed on the cards, they spit out virus, which specific tests can then detect.

We are also investigating whether mosquito poo could be used to enhance the sugar-based surveillance system. Mosquitoes spit only tiny amounts of virus, whereas they poo a lot (300 times more than they spit).

This mosquito poo can contain a treasure trove of genetic material, including viruses. But we’re still working out the best way to collect the poo.

Mosquito poo, shown here after mosquitoes have fed on coloured honey, can be used to detect viruses like Murray Valley encephalitis.
Dagmar Meyer

Staying safe from Murray Valley encephalitis

There is no vaccine or specific treatment for the virus. Avoiding mosquito bites is the only way to protect yourself from the virus. You can do this by:

  • wearing protective clothing when outdoors

  • avoiding being outdoors when the mosquitoes that transmit the virus are most active (dawn and dusk)

  • using repellents, mosquito coils, insect screens and mosquito nets

  • following public health advisories for your area.

The virus is very rare and your chances of contracting the disease are extremely low, but not being bitten is the best defence.The Conversation

Ana Ramírez, PhD candidate, James Cook University; Andrew Francis van den Hurk, Medical Entomologist, The University of Queensland; Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney, and Scott Ritchie, Professorial Research Fellow, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How do we save ageing Australians from the heat? Greening our cities is a good start



File 20190227 150698 rrobo4.jpg?ixlib=rb 1.1
A shade tree makes a big difference to the comfort of this couple.
Nancie Lee/Shutterstock

Claudia Baldwin, University of the Sunshine Coast; Jason Byrne, University of Tasmania, and Tony Matthews, Griffith University

Heatwaves have killed more Australians than road accidents, fires, floods and all other natural disasters combined. Although recent research shows extreme cold is a worry in some parts of Australia, our hottest summer on record points to more heat-related deaths to come. The record heatwaves have highlighted the damaging effects of heat stress. Understandably, it’s becoming a major public health challenge.




Read more:
2018-19 was Australia’s hottest summer on record, with a warm autumn likely too


The risk of extreme heat events and the adverse impacts on older people has been extensively discussed in research. Remarkably, very little attention has been paid to the role of urban greenery in reducing heat stress for seniors.

Older people are particularly at risk of heat stress. Pre-existing medical conditions and limited mobility increase their vulnerability. Deaths of older people increase during extreme heat events.

The physical features of urban areas shape the capacity of older adults to engage in many activities when it’s hot. These include vegetation volume and coverage, thermal design, and the extent of shading in public areas and walkways. Increasing urban greenery may offer a way to improve older people’s comfort and social experience.




Read more:
Building cool cities for a hot future


Ageing adds urgency to greening

It is expected 20% of the global population will be older than 60 by 2050. The figure for Australia is even higher, at 23%. This means that by 2050 around one in four Australians will be more vulnerable to extreme heat.

Older people are more vulnerable to heat stress.
PorporLing/Shutterstock

Climate change may make the problem worse by fuelling even more extreme heat events.

Planning our urban centres to meet the needs of a rapidly ageing population is a matter of urgency. Urban greening to reduce their vulnerability to heat stress should be central to this agenda. It can also improve people’s quality of life, reduce social isolation and loneliness, and ease the burden on health systems.

An important task is matching the design of communities with the needs of an ageing population. Where older adults live and the quality of their local areas strongly influence their lived experiences. Yet recent research found the experiences of seniors were often not accounted for in research on neighbourhood design.




Read more:
Eight simple changes to our neighbourhoods can help us age well


What about aged care?

People face choices about where they live as they age. The common choices are to “age in place” or to move into aged care.

Ageing in place includes living in one’s own home or co-habiting with relatives or friends. Around 90% of Australian seniors choose this option, with the remainder opting for aged-care facilities.

If one in ten Australian seniors live in aged-care facilities, it is clear these should be designed to minimise heat stress. This isn’t just good for residents; it may also benefit operators by lowering health-care and electricity costs.

While these facilities are purpose-built for older people, many in Australia were built well over a decade ago, when heat stress was not such a large concern. Many more facilities are being built now and will be into the future. Yet it is uncertain whether they are being actively designed to reduce the impacts of heat.




Read more:
Australian cities are lagging behind in greening up their buildings


What has our research found?

We recently conducted a focus group to investigate this issue. Participants were senior managers from four large corporate providers of aged care in Australia. We investigated if and how providers try to minimise heat stress through design. We also sought to understand the rationales used to support these design approaches.

Several participants reported on refurbishments that they expect will have cooling effects. Cited design approaches included green roofs and walls, as well as sensory gardens. Other expected benefits included reducing anxiety and improving the mental health of residents.

The fact that single design interventions could produce multiple benefits improved the potential for corporate buy-in. Participants expected that increasing green space and green cover would give their facilities a competitive advantage by attracting more clients and providing a better working environment for staff.

Participants also reported on challenges of including greening in their projects. For example, the benefits of trees were weighed against concerns about roots disrupting footpaths and becoming trip hazards. Species selection was another concern, with fears that inappropriate plants could die and undermine support for greening programs.

Our research suggests that more can be done to make cities hospitable for older people, especially during extreme heat. Urban greening is a start. Encouraging aged-care providers to adopt green infrastructure will have benefits. But we should also consider reforms to planning systems and urban design to better protect older people who choose to age in place.




Read more:
If planners understand it’s cool to green cities, what’s stopping them?


The Conversation


Claudia Baldwin, Associate Professor, Urban Design and Town Planning, Sustainability Research Centre, University of the Sunshine Coast; Jason Byrne, Professor of Human Geography and Planning, University of Tasmania, and Tony Matthews, Senior Lecturer in Urban and Environmental Planning, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.