Swimming is a pleasurable sport which makes one feel cool, refreshed and energetic. But there are certain health hazards associated with it. One can get sick due to swimming in lakes or swimming pools due to various kinds of microbes present in water. Water is contaminated due to faecal matter, and urine of humans, birds and animals and also by washing and cleaning activities. Germs get access to the body during swimming, wading or bathing in water bodies by water entering the mouth— swallowed or entering the gut— water entering the nose and from there, to air sinuses. It enters directly in the ears, from where germs can reach the brain. They can enter the body through a pre-existing wound or sore. Chlorine present in treated water causes inflammation of the skin, nasal and ear mucosa, that is, protective inner linings, thus disrupting them and making them more prone to infection. One can get problems related to the ear, brain, skin, intestinal infections and systemic disease. Infections can be bacterial like Escherichia coli, Shigellosis. These can cause acute or recurrent diarrhoea which may be liquid and or with blood and mucous, with abdominal cramps, bloating, nausea, vomiting, one or more of these symptoms. Severe diarrhoea can be fatal due to renal failure and or shock. Diagnosis is based on identifying causative germs, treatment is by suitable antibiotics. Pseudomonas leads to resistant ear and skin infections, manifested by ear pain, discharge, fever and skin eruptions. It is diagnosed microscopically and is treatable by suitable antibiotics. Simple upper respiratory tract infections like cold and cough can occur due to swimming. Bacterial infections can spread from nose to sinuses causing sinusitis manifesting as persistent headache. The brain can be infected via the ear causing serious illness. Spirochaetal infection like leptospirosis occurs due to swimming in water contaminated by urine of animals. There is fever, jaundice, body ache, rash and petechial spots on the skin. Diagnosis is made by identifying the organism and treatment is by antibiotics. Protozoal infections — Giardiasis— is caused due to swimming in contaminated water; causes repeated are acute or chronic diarrhoea, a bloating sensation in the abdomen, malabsorption and malnutrition. The protozoa are easily identified in stool samples and are treatable. Amoebic meningoencephalitis is a rare infection caused by naegleria fowleri, colloquially known as the “brain-eating amoeba” and enters the nose by inhalation of contaminated water, reaches the brain and damages brain tissue. Infection leads to loss of smell, headache, mental disturbances and or paralysis of body parts. It usually is not detected in the early stages and is often fatal. Viral infections like hepatitis A can occur due to ingestion of contaminated water, others include, jaundice, loss of appetite, vomiting and enlargement of liver. Fungal infection can occur due to dampness caused by swimming. Moist areas of the body like the armpits and genitals are more prone to it, manifested by skin rashes and itching and treatable by anti-fungal medications. Parasitic infection like Cryptosporidium parvum is asymptomatic initially but can spread to other body parts, manifesting as malaise, fever, anorexia, and or vomiting. The eggs passed are resistant to chemical disinfectants and can be excreted for several days after patient feels better. Schistosomiasis occurs due to swimming in water infested with snails. The larvae released by snails penetrate human skin. Initially it causes itching. Gradually they multiply and reach other visceral organs causing damage to the liver, kidney and other body parts. Diagnosis is made by microscopic examination of larvae in stool or urine samples. It is treatable in early stages but once liver and kidney damage occurs, treatment is difficult. Keep mouth closed or if open avoid swallowing. Spit out any water ingested as soon as possible. Avoid urinating or spitting while inside the water. Take a shower with clean fresh water immediately after. Rinse your mouth and eyes with fresh water. Avoid swimming if you have a cold, cough, sore, blister or wound somewhere on your body. Dr Rachna Pande, Specialist, internal medicine rachna212002@yahoo.co.uk