Risks From Water
Swimming
A variety of infections (e.g., skin, ear, eye, respiratory, neurologic, and diarrhoeal infections) have been linked to wading or swimming in the ocean, freshwater lakes and rivers, and swimming pools, particularly if the swimmer's head is submerged. Water may be contaminated by other people and from sewage, animal wastes, and wastewater run-off. Diarrhoea and other serious waterborne infections can be spread when disease-causing organisms from human or animal feces are introduced into the water. Travellers who swim should be advised to avoid beaches that may be contaminated with human sewage or dog feces.
Accidentally swallowing small amounts of faecally contaminated water can cause illness. Travellers should be warned to try to avoid swallowing water while engaging in aquatic activities. Generally, for infectious disease prevention, pools that contain chlorinated water can be considered safe places to swim if the disinfectant levels and pH are properly maintained. However, some organisms (e.g., Cryptosporidium, Giardia, hepatitis A, and Norovirus) have moderate to very high resistance to chlorine levels commonly found in chlorinated swimming pools, so travellers also should avoid swallowing chlorinated swimming pool water. All travellers who have diarrhoea should refrain from swimming to avoid contaminating recreational water.
Travellers should be advised to avoid swimming or wading with open cuts or abrasions that might serve as entry points for pathogens. In certain areas, fatal primary amebic meningoencephalitis has occurred after swimming in warm freshwater lakes or rivers, thermally polluted areas around industrial complexes, and hot springs, so travellers should avoid submerging the head and should wear nose plugs when entering untreated water to prevent water getting up the nose. Travellers should also be advised to avoid wading or swimming in freshwater streams, canals, and lakes in schistosomiasis-endemic areas of the Caribbean, South America, Africa, and Asia (see Map 4-10, Geographic distribution of schistosomiasis), or in bodies of water that may be contaminated with urine from animals infected with Leptospira.
Risks from drinking
