**4. Settings Other Than Drinking Water, and the Range of Water-Related Diseases**

Drinking water is not the only route through which potentially contaminated water may affect individuals; bathing water is another important pathway. As argued above, modelling is challenging, and this is especially the case given the multiple number of potential exposure points. Water quality modelling is currently possible, and could be extended to include climate change. Warning the public about water risks in relation to bathing water is one way to address changing risks associated with climate change [49].

Infections can be related to exposure to natural and man-made recreational waters. These include thermal waters (amoebae, *Legionella*) [50], inland recreational fresh waters, ponds and lakes (cyanobacteria, *Pseudomonas aeruginosa* [51], enteric pathogens, *Leptospira* spp., *Trichobilharzia* spp. [52], *Schistosoma* spp. [53], *Vibrio* spp.) [54], wild swimming (enteric pathogens), coastal waters including sea sports, sea water pools, bathing beaches (dinoflagellates and diatoms, jelly-fish larvae, toxic seaweed, enteric pathogens) and the beach environment, including run-off from fields and sewers, beach sand, and so forth. Recreational exposure to man-made fresh water pools includes treated swimming pools (*Cryptosporidium*), natural pools (enteric pathogens), spa baths (*P. aeruginosa* [55], *Legionella* spp.), water parks (*Cryptosporidium* spp.), foot wash and foot spas (*Mycobacterium* spp. [56] and *P. aeruginosa* [57]) and inflatables (*P. aeruginosa*, *Aeromonas hydrophila* [58]).

Infections from working in water can include *Schistosoma* spp., *Burkholderia pseudomallei* [59] and wound infections from water (*Vibrio vulnificus* [60], *Mycobacterium* spp., [61] *B. pseudomallei* [62]). Water transmission in man-made systems and equipment includes hospital/medical uses of water, water for dialysis and hydration (cyanobacteria), water for washing and decontamination, hospital water systems, water transmission in intensive care (*P. aeruginosa*) [63–66], contaminated equipment including endoscope washers (*Mycobacterium* spp.) [67], humidifiers, taps and wash basins, showers (*Legionella* spp.) and water births [68–71]. A variety of industrial waters can contribute to respiratory infection, including cooling towers and thermally polluted waters (*Legionella* spp.).

The disposal of waste can contribute to water contamination, particularly chemical contamination, but also pathogens. Sewage disposal is the main source of human faecal contamination in developed countries and sewage treatment is designed to reduce this to a minimum. However, animal waste probably represents a larger input to the natural environment as a result of defecation on fields and run-off. In developing countries, human faeces are commonly deposited in the natural environment at defaecation sites or middens where the 'night soil' matures over time and some pathogens require this to become infectious (*Ascaris lumbricoides* [72], *Cyclospora cayetanensis*). There are also potential risks associated with water passing through waste burial sites, particularly mass graves associated with plague, smallpox or anthrax, and from water running from leather processing sites (*Bacillus anthracis*).

Water is important in agriculture and food production, and irrigation may be conducted with water that is not of potable quality. Where this is done for salad items and soft fruit that are eaten without further treatment, then outbreaks can occur [73,74]. Contaminated water used for washing and food processing can also cause outbreaks. Food retailers require water on the premises in order for staff to wash their hands. Water-related foodborne disease (water-based) includes helminths and other macro-parasites, ciguatera, shellfish dinoflagellate toxins and similar toxins [75]. As shellfish filter large volumes of water, there are common outbreaks associated with faecal pathogens (especially norovirus and *Vibrio cholerae* [76], *Vibrio parahaemolyticus* [76] and *Vibrio vulnificus* [76]). Many processed drinks and foods contain water, and infections are prevented by source water protection, filtration, heat treatment or preservative treatment and a matrix that prevents pathogenic organisms from multiplying.

Where water is in short supply, water washed diseases may occur [14]. This can be in desert areas where lack of water and chronic water shortages, together with flies resulting from poor waste disposal, can allow the transmission of enteric (shigellosis) and eye infections (*Chlamydia trachomatis*).

Vector borne diseases (mosquito-borne, tick-borne, fly-borne, triatomid bug) can be strongly influenced by weather and geographic parameters, are likely to change in distribution as a result of climate change and are difficult to predict accurately [77], but are not examined further in this paper.
