Legionellosis (Legionella): caused by Legionella bacteria, this is an infectious disease that can be caught by anyone, but elderly gardeners and those with a suppressed immune system are most vulnerable. There are two types to which gardeners may be exposed: Legionella longbeachae, occuring in soil and compost, which can lead to a respiratory disease; and the more common L. pneumonophila, which leads to a type of pneumonia known as legionnaires disease. The latter form occurs naturally at low levels in watercourses but can multiply in standing water to potentially harmful levels when the water temperature is between 20°C to 45°C.
Bioaerosols: these are airborne micro-organisms including spores, bacteria and fungi (e.g. Aspergillus fumigatus) that are naturally present in decomposing material. Gardeners are most likely to breathe these in when turning compost, especially in warm weather. People with an existing chest conditions such as asthma or bronchitis or those prone to allergies are most at risk.
Tetanus: the tetanus bacterium can enter through cuts or wounds. Since gardeners regularly handle thorny plants, soil or manure, they are at a higher risk of being infected than non-gardeners.
Weil’s disease (Leptospirosis): this is a disease humans can catch from rats through water or wet vegetation contaminated with rat urine. Rats also transmit salmonella.
Plant hazards: as well as some plants being poisonous, there are also a number of plants whose sap or hairs can cause skin blistering, burns, rashes or breathing difficulties.