Changes in land management practices could lead to infectious diseases, researchers with the Menzies School of Health Research in Darwin, Australia say.
They have studied the soil bacteriums Burkholderia pseudomallei that
lives in tropical soil and is endemic in southeast Asia and northern Australia. It has been a common cause of fatal community-acquired bacterial pneumonia. In predisposed hosts such as those with diabetes, it can also lead to systemic sepsis, with mortality rates over 50 per cent.
The researchers found bacterium is associated with land management changes such as livestock husbandry or residential gardening. The study, published 20 January in the open-access journal PLoS Neglected Tropical Diseases
, sheds light on the environmental occurrence of this bacterium in the soil.
Through a large survey in the tropical Darwin area of Australia, the study's authors found that the environmental factors describing the soil habitat of B. pseudomallei
differed between undisturbed sites and environmentally manipulated areas. At undisturbed sites, B. pseudomallei
was primarily found in close proximity to streams and in grass-rich areas, whereas at environmentally disturbed sites, B. pseudomallei
was associated with the presence of livestock animals, lower soil pH and irrigation. Highest B. pseudomallei
counts were retrieved from paddocks, pens and kennels holding livestock and dogs.
"These findings raise concerns that B. pseudomallei
may spread due to the influence of land management changes," said study author Dr Mirjam Kaestli. "This would increase the risk of human and livestock exposure to these potentially deadly bacteria which are transmitted by contact with contaminated soil or surface water through cuts in the skin or inhalation."
In-depth analysis of the influence of anthropogenic factors upon B. pseudomallei
and further studies in other endemic areas are needed to confirm the results of this study.