EPA WARNS OF SWIMMING RELATED ILLNESSES

FROM:  U.S. ENVIRONMENTAL PROTECTION AGENCY 

Human Health

Most of the time when beaches are closed or advisories are issued, it's because the water has high levels of harmful microorganisms (or microbes) that come from untreated or partially treated sewage: bacteria, viruses, or parasites. We also use the word "pathogens" when they can cause disease in humans, animals, and plants.
Illnesses.

hildren, the elderly, and people with weakened immune systems are most likely to develop illnesses or infections after coming into contact with polluted water, usually while swimming. The most common illness is gastroenteritis, an inflammation of the stomach and the intestines that can cause symptoms like vomiting, headaches, and fever. Other minor illnesses include ear, eye, nose, and throat infections

Fortunately, while swimming-related illnesses are unpleasant, they are usually not very serious - they require little or no treatment or get better quickly upon treatment, and they have no long-term health effects. In very polluted water, however, swimmers can sometimes be exposed to more serious diseases like dysentery, hepatitis, cholera, and typhoid fever.

Most swimmers are exposed to waterborne pathogens when they swallow the water. People can get some infections simply from getting polluted water on their skin or in their eyes. In rare cases, swimmers can develop illnesses or infections if an open wound is exposed to polluted water.

Not all illnesses from a day at the beach are from swimming. Food poisoning from improperly refrigerated picnic lunches may also have some of the same symptoms as swimming-related illnesses, including stomachache, nausea, vomiting, and diarrhea.

It is also possible that people may come into contact with harmful chemicals in beach waters during or after major storms, especially if they swim near what we call “outfalls,” where sewer lines drain into the water. You can learn more about this by visiting our web site for stormwater.

Finally, the sun can hurt you if you're not careful. Overexposure can cause sunburn, and over time, it can lead to more serious problems like skin cancer. The sun can also dehydrate you and cause heat-related illnesses like heat exhaustion, muscle cramps, and heat stroke. Learn more about sun safety at our SunWise site or heat-related illnesses at the Centers for Disease Control and Prevention site.

How to Stay Safe

There are several things you can do to reduce the likelihood of getting sick from swimming at the beach. First, you should find out if the beach you want to go to is monitored regularly and posted for closures or swimming advisories. You are less likely to be exposed to polluted water at beaches that are monitored regularly and posted for health hazards.

In areas that are not monitored regularly, choose swimming sites in less developed areas with good water circulation, such as beaches at the ocean. If possible, avoid swimming at beaches where you can see discharge pipes or at urban beaches after a heavy rainfall.

To find out about the beaches you want to visit, contact the local beach manager.

Since most swimmers are exposed to pathogens by swallowing the water, you will be less likely to get sick if you wade or swim without putting your head under water.

THE WORLD OF MICRO-LOCOMOTION

FROM:  NATIONAL SCIENCE FOUNDATION 

Microorganisms: Studying the mechanics of their locomotion

Research has potential for improvements in treating diseases and reproductive health and creating new drug delivery systems

Bacteria often must swim through intricate environments in the human body to get where they need to go. How they do it is what fascinates Henry Fu.

"A microbiologist might look at the biology, or biochemical pathways," says Fu, an assistant professor of mechanical engineering at the University of Nevada, Reno. "I am focused on the mechanics, rather than the biology."

Fu's goal is to understand the locomotion of bacteria and other microorganisms, such as sperm and protists, when they swim through such complex substances as mucus or bodily tissues. While both do contain fluid, they are more complicated than water, and bacteria almost certainly need different forces to navigate through them.

"People have tried to understand how they swim through regular water for a very long time, probably 50 or 60 years, but I want to know how this swimming is modified when they are swimming through things more complicated than water, like mucus," says the National Science Foundation (NSF)-funded scientist. "Mucus is more viscous and has elastic properties. People think of mucous as smooth and continuous, but it has a network of fibers. I'm looking at how those fibers interact with the microorganisms."

His work potentially has broad implications in the treatment of diseases, for example, in figuring out ways to block infection by halting a bacterium's movement, even after it has entered the body, such as in Lyme disease, where "bacteria have to burrow through your tissues to get to your bloodstream," Fu says. "Understanding how they do that could be potentially important in order to stop them."

The research also could prove valuable in reproductive health, where "the properties of mucus can affect the likelihood of fertilization," Fu says. "This could be important in treating infertility or contraception, when you could make it easier--or harder--for the sperm to move."

Researchers also could apply mechanical engineering lessons learned toward creating new drug delivery systems, such as nano-robots that could carry chemotherapy through the body to target a growing tumor.

Microorganisms swim by moving parts of their bodies. For example, many swimming bacteria have a tail-like flagellum, which rotates like a propeller, pushing them forward, while some algae have two flagella that "they can use like breast stroke," Fu says. "Part of what I am looking at is how they translate this motion into propelling themselves in the direction of where they want to go."

His research mostly is theoretical--in the computer and with pen and paper--designing models of these swimmers to see how they behave in different environments, and with variations to their swimming motions.

"What we do as modeling is based on well-known fundamental physics laws," he explains. "We could tell the computer the shape of a bacterium and its swimming motion, or how it is rotating, and the properties of the material or fluid it is moving in. We then ask it how it will move, and how much force and energy it will take. We might also ask what might happen if the flagellum or cell had a different shape."

Fu is conducting his research under an NSF Faculty Early Career Development (CAREER) award, which he received in June 2013. The award supports junior faculty who exemplify the role of teacher-scholars through outstanding research, excellent education, and the integration of education and research within the context of the mission of their organization. He is receiving $400,003 over five years.

As part of the grant's educational component, he plans to create "Move Like a Microbe," a simulation of microscale microbial locomotion that "will bring the research to life for the public, and K-12 students, by providing a hands-on demonstration of how microorganisms are able to swim, and explain the consequences of microbial locomotion in everyday life," he says.

"Because microorganism are so small and because what they experience in a fluid environment is different from what we expect, this demonstration helps put them in the shoes of a microorganism," he adds. "They can control it, and make it swim, and feel the forces that the microorganism feels--and they will be learning about what it's like to try to swim when you're a tiny thing."

-- Marlene Cimons, National Science Foundation
Investigators
Henry Fu