Soil & public health

Soil & public health. IL Pepper, 19th World Congress of Soil Science, Brisbane, August, 2010.

Soil-associated infection can be thought of as:

• geoindiginous – native to soil
• geotreatable – inactivated if introduced to soil
• geotransportable – carried via soil e.g. septic tank systems

Three of the four major groups of microorganisms are involved:

1. Bacteria – Bacillus anthracis, Legionella longbeachae, Clostridium perfringens, Burkholderia pseudomallei
2. Fungi – Coccidioides immitis, Histoplasma capsulatum
3. Protozoa – Naegleria fowleri, Balamuthia mandrillaris

Viruses do not feature due to the lack of a human host in the soil. Examples of potentially geotransportable microorganisms include large movements of airborne dust such as the Mongolian dust cloud over the Sea of Japan. The list of biotreatable bacteria, helminths, protozoa and viruses is long since it includes the content of biosolid waste and waste waters e.g. adeno- and Norwalk viruses, Salmonella, E.coli O157:H7, microsporidia, Giardia & Ascaris.

Soil science and its microbial content has yielded antibiotics including penicillin and streptomycin, but soil also contains intrinsically antibiotic resistant bacteria.

• What we breathe: soil particles – fibrous mineral particles including asbestos, silica & radon
• What we drink - arsenic seeping into drinking water in Bangladesh, well design to avoid cholera and other water-borne infections, but benefits from Calcium, Magnesium & Fluoride micronutrients
• What we eat – benefits directly through nutrition, possibly affected by microbial growth kinetics, but potential exposure to geotransported microorganisms
• What we think – e.g. protozoal infections due to free-living amoebae, sporadic  & generally attributed to soil or surface exposure
• What medicates us – soil = treasure chest of natural products, endophytes, metagenomic analysis of soil, possible beneficial impact through microbial respiration on global warning, through carbon sequestration

The MicroGnome’s talk on Sinister Soils & Risky Rhizospheres followed immediately after Dr Pepper’s talk.

Notes by the MicroGnome.