Turning up the heat on health and climate change

With the scientific community agreeing the Earth is warming, climate change and what to do about it are topics of wide debate.

While some of the climate change impacts are widely known, including drought, melting glaciers, coastal erosion and the bleaching of coral reefs, including Australia’s World Heritage listed Great Barrier Reef, researchers are also exploring the impacts of climate change on our health.

Alumna Dr Adriana Milazzo, Senior Lecturer and epidemiologist at the University of Adelaide, says there are a number of infectious diseases that are “climate driven.”

“Malaria is one, along with Salmonella, Cholera and Campylobacter bacterial infections, which causes gastroenteritis. In Australia, Ross River virus, which is a mosquito borne disease is also sensitive to climate change,” said Adriana.

Adriana’s PhD looked at the relationship between heatwaves and risk of Salmonella infection in South Australia and found that, “overall, reported incidence of Salmonella poisoning is 34 per cent higher during heatwaves.”

“Bacterial infectious agents such as Salmonella that cause foodborne disease are sensitive to temperature variability, and in warmer temperatures the rate of replication is high,” said Adriana.

“We found that sustained elevation in temperatures can affect transmission of Salmonella infection directly, by both the multiplication of bacteria in the environment and in food, and indirectly with changes in people’s eating behaviour. For example, people are more likely to eat outside and have barbeques during summer.”

In the study, participants were asked questions around their food handling and storage practices. Adriana said while it was no surprise to find that many people didn’t know the correct temperature at which to set their refrigerator, what was interesting was people’s food safety practices.

“There were different practices around use of chopping boards for example. Some people used the same chopping board for raw meat and other food. “There were also great differences in how people washed their boards. Most people used hot soapy water, but then there were others who used lemons, or wiped them down,” Adriana said.

How some people defrosted raw meat was also a concern, with some leaving meat out to thaw at room temperature for more than four hours.

“There was a high proportion of people who did that, which is an issue because if there is bacteria in the raw food, it will multiple and grow when it’s hot,” said Adriana. In addition to examining the impact of climate change on food borne infections, researchers are also examining the impact of climate change on vector borne diseases – infectious diseases transmitted to humans and animals by ‘blooding anthropods.’ In humans, these are mainly diseases transmitted by mosquitos, including Malaria and, in Australia, Ross River virus.

“In southern parts of Australia like South Australia, increases in Ross River virus infection in humans is seasonal. It’s driven by warmer ambient temperature and also rainfall. So if there is a lot of rainfall and there’s flooding in particular areas, then we find potential increases in Ross River virus because mosquitos like to breed in stagnant waters,” said Adriana.

Ross River has some long-term impacts on human health including aching joints, chronic fatigue and painful/swollen joints. Adriana says prevention is “around making sure you cover up and you use repellent, and making sure that there isn’t any stagnant water lying around for mosquito breeding.”

In other research, Adriana is looking at heatwave policies in schools, to ultimately determine whether there should be a national policy and what a good policy looks like.

Adriana’s expertise in infectious diseases has also been called on to help monitor and mitigate the spread of COVID-19. She has been working on developing training material for COVID-19 contact tracing. On another project, she is looking at the public health interventions for COVID-19 applied in South Australia and Victoria, and doing a comparison of the trajectory of cases.

“What COVID-19 has done is highlight the importance of public health, and climate change is a public health issue. I am hopeful that climate change will be taken more seriously.

“We are doing some great work in South Australia around adaptation and heat messaging – getting the early warning systems out. But I think we need that kind of commitment, that political will higher up, including reducing emissions,” said Adriana.

Hear more about University of Adelaide researchers’ work in climate change and other fields on the Discovery Pod Podcast, where leading experts from the University of Adelaide discuss solutions to society's most pressing challenges. 

Food summer safety tips

• Make sure your fridge is clean, uncluttered and set at 5°C or less.
• Prepare food near to the time it is going to be served.
• Defrost foods in the fridge or the microwave, not on the kitchen bench.
• Put leftovers in the fridge as soon as they stop steaming.
• Never leave food in a hot car.
• Take insulated cooler bags to the shops to carry home chilled and frozen foods.
• Immediately pack chilled and frozen foods in the fridge and freezer when you get home.
• Don't leave food out for too long (never more than two hours out of the fridge).
• Keep leftovers in fridge and eat within two-three days.
• Use a different chopping board for chopping meat.
• Wash chopping boards in hot soapy water.

Sourced from Dr Adriana Milazzo and the SA Health website.

Story by Kelly Brown.