This is a very dangerous disease because of the very low amount of contact required for infection, as well as the potential for severe health consequences. E. coli is thought to be the cause of over 90% of all cases of diarrhea-associated hemolytic uremic syndrome, a condition that mostly affects young children and causes acute renal failure. This disease is most commonly contracted from swimming in contaminated fresh waters, although even chlorinated waters can still contain E. coli if it is not properly sanitized.
Hepatitis A is caused by a virus, so it does not respond to antibiotics, making it harder to get rid of once it is contracted. It can be contracted by eating contaminated foods or swimming in contaminated waters, but it becomes significantly more of a risk in places where large numbers of people congregate, especially if there is inadequate sanitation.
Also known as Norwalk virus and epidemic viral gastroenteropathy, this disease has been linked to outbreaks on many cruise ship lines. More specifically, this virus has been linked to transmission through hot tubs and spas in most outbreaks of the disease.
A particularly dangerous disease, schistosomiasis is also referred to as “snail fever” because it is contracted by swimming in lakes or ponds where snails are plentiful. Initially, the symptoms will include diarrhea and abdominal pain, but they can eventually lead to reduced liver functioning and in extreme cases, colorectal cancer.
Also known as Canicola fever, Weil disease, hemorrhagic jaundice, mud fever, and Swineherd disease, leptospirosis is a bacterial disease that is the result of waters being contaminated by the urine or domestic and wild animals. It is characterized by fever, chills, severe myalgia, jaundice, rash, and hemorrhage into the skin or mucous membranes.
This disease is an infection that primarily affects the small intestine. Although it can remain asymptomatic, giardiasis also has the potential to lead to intestinal disorders such as chronic diarrhea, steatorrhea, abdominal cramps, bloating, weight loss, and malabsorption of fats and vitamins. This disease more commonly affects children and is most often the result of drinking or swimming in poorly sanitized waters, but it can also be found in contaminated swimming pools.
This disease is caused by the Shigella species, and it is most commonly contracted by swimming in pools and spas. Shigellosis is characterized by fever, nausea, vomiting, cramps, and diarrhea, and it takes a very low dose (10-100 organisms) of consumption to cause these symptoms.
Pseudomonas is most commonly associated with “swimmer’s ear,” as well as some skin infections. This bacteria thrives in warm water environments, such as hot tubs and spas. When in the form of a skin infection, it looks like a rash that resembles chicken pox. These symptoms can be the result of swimming in contaminated waters such as hot tubs, whirlpools, spas, and water parks.
Cryptosporidiosis is the result of a parasitic infection, and it can affect more than 45 other vertebrate animals besides humans. Since it is common for the infection to be asymptomatic, it makes it easier to spread the disease to others. When symptoms do become present, they usually include diarrhea, severe abdominal cramping, malaise, fever, anorexia, and vomiting. Since it is spread through the fecal-oral route, this disease can be found in any form of contaminated water that has not been sanitized properly.
Naegleriasis and Acanthamoebiasis
These organisms, commonly referred to as "free-living bacterias," have been linked to infections of the eyes and skin. For people who wear contact lenses, exposure through a spa or hot hub has been the source of corneal infections, though most of the time, the infection is spread through lakes and ponds. Even so, people who wear contact lenses should take precaution by not wearing their lenses while swimming.