Tuesday, January 20, 2009

Could Farming in the Tropics Promote a Killer Disease?

This is the premise being actively promoted in a new study of the disease meliodosis, based on results from the Northern Territory of Australia. Meliodosis is deadly........without active and well managed treatment you die. At least in the NT, there is a good quota of experience with the disease and mortality rates are now around 20%. Still, that is very high.

The disease also occurs in SE Asia in the tropics - Thailand, Laos, Malaysia etc, and is something to be mindful of when involved in agriculture in these areas.

Read the press release.........

Gardening and farming in the Australian tropics creates an environment "ideal" for the spread of a killer bacteria, a scientist has warned. Darwin-based researchers have worked to identify the soil types favoured by the bug Burkholderia pseudomallei, which is now at the centre of an outbreak of a pneumonia-like illness in the NT capital. Ten people have been infected, and two have died, from the illness Melioidosis since the wet season began late last year.

Dr Mirjam Kaestli says the bacteria was thought to favour damp soil and areas where there was standing water, but her research also found it thriving in household lawns and dry paddocks across rural Darwin. "These findings raise concerns that pseudomallei actually might spread due to the influence of our land management changes," says Dr Kaestli, who is a research fellow at the Tropical & Emerging Infectious Diseases Division at the Menzies School of Health Research. "Residential gardening and farming generates conditions which are ideal for the proliferation of these pseudomallei.

"We primarily found the bacteria in irrigated lawn areas like on residential properties ... also soil disturbance caused by livestock animals seem to increase survival chances for pseudomallei in areas otherwise not favourable."

It is thought the constant aeration of paddock soils from hoofs, along with raised acid levels from urine, encourage the growth of the bacteria.

The Royal Darwin Hospital treats up to 40 cases of melioidosis every wet season and, while it has a 20 per cent mortality rate this has halved over the past 15 years because of improved diagnosis and treatment. It is listed as an emerging disease, with cases rising in Thailand, and Dr Kaestli warns there were concerns the number would also increase in Australia.

Melioidosis cases have been detected as far down the eastern seaboard as Brisbane.

"Because we have seen this association with disturbed soil, and because there are more and more developing of previously undisturbed area, I would not be surprised if we are seeing higher numbers in the future," she said. People with type-2 diabetes, chronic lung and renal disease, heavy alcohol consumers or those who use of immunosuppressant drugs are known to carry an increased risk of contracting Melioidosis. Dr Kaestli said people in the tropical areas should take precautions by wearing shoes when working in the garden, washing their hands later with an anti-bacterial and taking extra care to keep cuts dirt free.

Her study is published in the journal PLoS Neglected Tropical Diseases.

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