Thursday, 23 March 2017

The climate change debate in Australia often focusses on temperature, rainfall and sea levels, but......

There’s more to climate change impacts than living in a markedly hotter, drier continent being nibbled at the edges by encroaching oceans or battered by storms - and it isn’t only the very real threats to the natural environment, biodiversity and water security.

There’s the risk of an increased incidence of disease outbreaks in humans and animals and, the economic and social costs rising levels of disease bring to families, communities, local economies and the nation.

The Sydney Morning Herald, 30 April 2015:

A range of tropical diseases will become more widespread in Australia due to climate change, including a dramatic increase in mosquito-borne illnesses, scientists warn. Their research has prompted leading doctors to call for a co-ordinated response from the federal and state governments to the pending crisis. 

In a paper released on Thursday, the Australian Academy of Science said diseases currently confined to the tropics would be unlocked and travel south. The incubation period for mosquito-borne diseases such as dengue would also be shortened.

Rising temperatures and changes to water availability were also likely to increase the prevalence of food and water-borne diseases. The scientists forecast an increased risk of respiratory diseases as more people spend time indoors to avoid extreme heat, and population density increases due to population growth.

"A clear problem facing Australia as it prepares to deal with the problem of the rise in infectious illnesses triggered by climate change is its lack of a single centre through which information about communicable diseases can be co-ordinated and disseminated," the paper said.

Excerpt from Australian Academy of Science report mentioned in the April 2015 news article:

Changes in disease burden anticipated in Australia’s future climate are:
* Vector-borne diseases (e.g. dengue, chikungunya) Breeding of vectors like the mosquito will probably alter because of ecosystem change and this will increase Australia’s susceptibility to outbreaks of vector-borne diseases. The expansion of disease ranges will put rising numbers at risk, while reductions in incubation times for vector-borne viruses will worsen the problem.
* Food-borne diseases (e.g. infections with E. coli, Campylobacter, Salmonella) Rising temperatures, changes to water supply and extreme weather events are likely to increase the incidence of human food-borne diseases. In addition, more prevalent animal bacterial infection and associated bio-security costs may disrupt food and livestock export markets. Increasing incidence of food-borne diseases could reduce the productive workforce.
* Water-borne diseases (e.g. Giardia, cholera) Changes to water availability and higher temperatures will increase the prevalence of water-borne diseases, while replication rates of bacteria will increase as temperatures rise, reaching higher densities and posing greater risk to more people.
* Respiratory diseases (e.g. influenza, whooping cough) As temperatures rise, more people will spend time indoors to avoid the extreme heat, increasing the risk they will pass on respiratory diseases. This problem will be exacerbated by changes in seasons, extension of peak transmission periods, and rises in human population density due to population growth. The displacement of people from other regions as a result of climate change will also increase the rate at which new diseases are brought into Australia and could add to population density.
* Zoonotic diseases (e.g. Hendra, leptospirosis) Climate change will alter the density and movement of both wild animals and livestock in Australia and affect human–animal contact patterns. This could promote transmission of existing zoonotic disease or increase the risk of novel diseases emerging., 5 August 2016:

A FLESH-eating ulcer that can result in limb amputations has made its way to Melbourne’s southeast suburbs, The Age reports.

The Buruli ulcer has hit record levels in Victoria with 45 cases reported this year. The disease has recently spread to inner Melbourne suburbs such as Bentleigh, Hampton and Cheltenham.

It’s believed the ulcer, also known as the Bairnsdale ulcer, can be contracted by contact with bodies of water, mosquitoes and even possums. However the exact mode of transmission remains unknown to researchers.

The disease eats at the skin and capillaries and can lead to gangrene if left untreated, resulting in amputation in extreme cases. It most commonly affects exposed skin areas such as arms and legs.

It was first recorded in Bairnsdale, Victoria in the 1930s, but has more recently been detected in the Mornington and Bellarine Peninsulas.
Austin Hospital’s Professor Paul Johnson told The Age the number of cases was “rapidly increasing. You’ve got this tropical disease in coastal temperate Melbourne.”

The Sydney Morning Herald, 2 September 2016:

Dozens of Australians have been infected with the Zika virus this year and there are concerns more will contract it while travelling in Asia where cases are proliferating.
On Friday, federal health authorities urged Australians to be careful while travelling to Zika affected areas, including Singapore where infections are soaring.

The Sydney Morning Herald, 14 January 2017:

Dengue fever cases in Australia reached a 20-year high last year, driven by travellers being infected in tropical areas such as Bali and bringing the virus back with them.

More than 2000 cases of the mosquito-borne disease were confirmed in Australia last year, federal Health Department data shows….

Microbiology professor Cameron Simmons, of the Peter Doherty Institute, said dengue fever was endemic (constantly being transmitted) throughout much of south-east Asia and the western Pacific, which were popular destinations for Australian travellers.

"Dengue has been a problem globally for 20 years, and in the last 10 years we have seen epidemic spread of the virus through many countries in our neighbourhood," he said. "The chance of travellers being infected may well be increasing."

ABC News, 9 February 2017:

Ross River virus cases are spiking in parts of Victoria and New South Wales this summer.

The Murrumbidgee Local Health District, which stretches from Albury to central-west New South Wales, has seen 264 reported cases of the mosquito-borne virus since the start of December.

It is a significant increase compared to other years — there were 96 cases across New South Wales over the same period in 2015-16.

Health authorities also are concerned about a potential increase in Barmah Forest virus and Sindbis virus.

"We're seeing a marked increase on what we would normally see," director of public health Tracey Oakman said.

"In January for [the health district] we had 148 cases, and in the month before we had 116, and that's a lot higher than what we would normally see.

There were 622 Ross River virus notifications across the whole of New South Wales in 2016, with 202 in December.

In January, there were 317 cases across the state.

Victoria had 314 diagnosed cases of the virus last year, and so far this year has had 548 cases up until Tuesday.

Heavy spring rainfall across north-east Victoria and southern New South Wales is one of the main contributing factors to the rise of Ross River fever cases.

The Australian, 12 March 2017:

A Victorian farm is in quarantine after a suspected case of deadly anthrax disease, the second case in the area in just over a week.
Agriculture Victoria confirmed on Saturday that a farm in Nyah, in the state’s northwest, has been quarantined and a suspected infected carcass destroyed. Results from testing are expected on Sunday and an Agriculture Victoria team will remain at the property until “no further infected animals are detected”. All at-risk animals have also been vaccinated.
The latest suspected case comes after a 34 sheep died at a Swan Hill farm on March 3, with testing confirming anthrax was present in one of the sheep. Anthrax is a bacterial infection commonly found in the soil during hot, dry conditions and it causes a rapid death once animals are affected. [my highlighting]

U.S. Centers for Disease Control and Prevention, What is anthrax?:
Anthrax is a serious infectious disease caused by gram-positive, rod-shaped bacteria known as Bacillus anthracis. Anthrax can be found naturally in soil and commonly affects domestic and wild animals around the world…..people can get sick with anthrax if they come in contact with infected animals or contaminated animal products. Contact with anthrax can cause severe illness in both humans and animals.
Anthrax is not contagious, which means you can’t catch it like the cold or flu.
People get infected with anthrax when spores get into the body. When anthrax spores get inside the body, they can be “activated.” When they become active, the bacteria can multiply, spread out in the body, produce toxins (poisons), and cause severe illness.
This can happen when people breathe in spores, eat food or drink water that is contaminated with spores, or get spores in a cut or scrape in the skin.

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