Poor water quality, what potential illness awaits you in the pool?

“I regularly encounter patients during my after-hours house visits that present with allergic reactions, viral and bacterial infections causing problems with the ears, throat, lungs, eyes, skin, and overall wellbeing. Many of these patients have reported participating in swimming activities both recreational and organised lessons in the last 48 hours of my consultation”.

Dr Molly Gorman, NSW Australia

Dr Gorman also noted that she had recently examined a mature woman that presented with severe lung malfunction, and after several examinations, it appeared that the damage to her lungs was what is typically seen by that of a long-term chain smoker. When the woman was questioned further it was identified that in fact she had never been a smoker but had been a swim instructor for the past 20 years in an indoor swimming facility.

When swimming in a pool with poor water quality the potential for infections and the types of illnesses that can be contracted are listed below:

  • Parasites
  • Cryptosporidium

Symptoms include watery diarrhoea, stomach cramps, nausea and vomiting, possibly leading to dehydration.
Millions of Cryptosporidium parasites can be released from an infected human or animal, according to the CDC.

According to Faculty of Medicine, Universiti Teknologi MARA, the reported prevalence of Cryptosporidium among patients with Gastroenteritis is 1% to 4% in Europe and North America and 1% to 37% in Africa, Asia, Australia, and South and Central America.


This germ is found in the fecal matter of a person who has been infected by Giardia. It has a tough outer shell that allows it to survive for up to 45 minutes even in properly chlorinated pools. Giardia is a common cause of recreational water illness (disease caused by germs spread through pool water) in the United States and can cause prolonged diarrhoea (for 1–2 weeks). It can make anyone sick.

Giardia is spread by swallowing water that has been contaminated with fecal matter containing Giardia.

Swallowing even a small amount of pool water that has been contaminated with the Giardia germ can make you sick.

During the past 2 decades, Cryptosporidium spp. and Giardia sp. have been associated with increasing outbreaks of swimming-associated gastrointestinal illness in the United States.

Escherichia coli (E coli)

Some kinds of E. coli can cause diarrhoea, while others cause urinary tract infections, respiratory illness and Pneumonia, and other illnesses.

Escherichia coli (E. coli) bacteria normally live in the intestines of people and animals.

The time between ingesting the STEC bacteria and feeling sick is called the “incubation period.” The incubation period is usually 3-4 days after the exposure but may be as short as 1 day or as long as 10 days. The symptoms often begin slowly with mild belly pain or non-bloody diarrhoea that worsens over several days. HUS, if it occurs, develops an average 7 days after the first symptoms, when the diarrhoea is improving.

Pseudomonas Aeruginosa

Pseudomonas aeruginosa accounts for many episodes of infections associated with attendance at swimming pools. The genus Pseudomonas includes free-living bacteria that are highly versatile and able to adapt to different environments and conditions. It is responsible for a series of diseases ranging from skin and eye infections in healthy individuals to serious life-threatening illnesses in burn, surgical, or immunocompromised subjects, often sustained by multi-drug resistant strains.
Folliculitus and ear infections which are caused by Pseudomonas aeruginosa.

This organism is responsible for skin (follicle) and mucous membrane infections and ear infections, particularly in kids, which tend to be difficult to treat. The organism proliferates very quickly in pools when the water temperature is greater than 26C and when disinfection levels are not maintained at all times. This organism also causes outbreaks in heated spa pools.

Due to its ability to form a biofilm on virtually all surfaces, Pseudomonas aeruginosa can survive in treated water with residual chlorine levels < 1 mg/L, in distilled water, and in disinfectant solutions, and it shows high resistance to mechanical cleaning processes.


This is a type of Gastroenteritis (also known as ‘gastro’) caused by Shigella bacteria. Only small numbers of Shigella bacteria are sufficient to cause an infection.

Symptoms may include:

  • Diarrhea (sometimes with blood or mucus)
  • Fever
  • Vomiting
  • Stomach cramps


Noroviruses are a group of viruses that can cause Gastroenteritis (inflammation of the stomach and intestines) with diarrhoea, stomach pain and vomiting. Common names used for Gastroenteritis due to Norovirus are ‘gastric flu’ or ‘stomach flu’, ‘winter vomiting’ and ‘viral gastro’. Apr 9, 2018

Hepatitis A

Since this virus is primarily transmitted via fecal matter, this is the hepatitis strain that could become a problem in a swimming pool.

A self-limiting viral infection of the liver, hepatitis A typically does not cause chronic disease. While hepatitis A causes liver inflammation, most people’s livers can fully recover without any long-term damage. However, people already afflicted with chronic liver disease are more susceptible to serious illness as a result of hepatitis A infection. Since this disease is caused by a virus, it does not respond to antibiotics.

The most common symptoms of Hepatitis A include:

  • Nausea, vomiting, diarrhoea
  • Low-grade fever and loss of appetite
  • Rash
  • Fatigue
  • Jaundice and dark urine
  • Liver pain


There are growing rates of people attending swimming pools for recreational, rehabilitative treatment or sport, especially in tropical area. Dermatophytosis, which is the most common fungal cutaneous infection, is a communicable disease mainly transmitted by human sources and swimming pools have high potential to transfer this infection.

Saprophytic fungi and yeast organisms have potential pathogenecity for Candidiasis, Otomycosis, Asthma and allergies (5, 9, 14).
Although susceptible persons may be infected from different places it should be noted that pool environments contribute to the spread of these agents.

Written by John Morrison BSc

2560 1536 HealthySwim

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