What’s in Annapolis’ Water? Swimming Risk in the Chesapeake Bay
No one in Annapolis has not at some point wondered if it was safe to swim in the Chesapeake Bay. What are the risks of contracting disease from swimming in the Bay around Annapolis? Summertime is here and water-related activity is increasing — and the perfect time to review what you can get, from where and how to avoid getting any of it.
We begin at the end — how to avoid getting anything from Bay water. One can avoid many infections following these 5 simple rules:
1. Bookmark this site: http://www.aahealth.org/programs/env-hlth/rec-water/reports. Do not swim in the Bay before checking this site. We are very fortunate to live in one of the best counties (Anne Arundel) in one of the best states (Maryland) for monitoring water quality. In particular, the Anne Arundel County Health Department does an amazing job reporting out areas that are safe or not safe.
2. After rainfall of 1/2 inch or more, all Anne Arundel County beaches are under a no swimming/no direct water contact advisory for at least 48 hours. Also, do not swim in cloudy, murky water.
3. Do not swim in the Bay if you have an ear infection, a perforated eardrum, open cuts, scratches or skin lesions, or a compromised immune system.
4. Do not swim in water areas where there is a fish kill or where there are any dead animals or known algae bloom.
5. Try not to swallow water while swimming
If you follow those 5 simple rules, you lower your risk for getting a water-related disease dramatically.
Water Related Illnesses
The CDC uses the term Recreational water illnesses (RWIs). RWIs are caused by germs spread by swallowing, breathing in mists or aerosols of, or having contact with contaminated water in swimming pools, hot tubs, water parks, water play areas, interactive fountains, lakes, rivers, or oceans. (RWIs can also be caused by chemicals in the water or chemicals that evaporate from the water and cause indoor air quality problems.) RWIs can be a wide variety of infections, including intestinal, skin, ear, lungs, eye, nervous system and wound infections.
The most commonly reported RWI is diarrhea. Diarrheal illnesses can be caused by germs such as Crypto (short for Cryptosporidium), Giardia, Shigella, norovirus and E. coli O157:H7.
In 2009, the Chesapeake Bay Foundation published a PDF claiming, “The Chesapeake Bay in summer is like a warm pond with a broth of nutrients at the right temperature to breed algae and bacteria.” We’ll briefly explore a few of these now.
Vibrio (“Flesh Eating Bacteria”)
This bacterial infection is sometimes referred to in the news as the “Flesh-eating bacteria”. There are several species of Vibrio. Vibrio vulnificus causes severe skin ulcers, gangrene, and deadly blood infections in people who expose cuts to warm saltwater containing the bacteria, as well as gastrointestinal illnesses in people who eat tainted shellfish.
Another species, Vibrio parahaemolyticus, causes diarrhea, vomiting, and skin infections, but is seldom deadly.
The best known is Vibrio cholerae which causes cholera, a diarrheal disease now virtually eliminated from the United States.
Harmful Algal Blooms and Cyanobacteria
One toxin-producing form of algae, called blue-green algae, is not really algae at all, but rather a class of bacteria, called cyanobacteria. There are at least 35 types of algae in the Chesapeake Bay that produce toxins. The most well known, Blue-green (Microcystis), is the cause of most blooms and fish kills reported.
A 2008 study reported that between 2000 and 2006, 31 percent of the waters tested with blue-green algal (cyanobacteria) blooms had enough toxins to make them unsafe for children to swim in.
According to the World Health Organization, Cyanobacterial toxins are classified by how they affect the human body. Some will affect the liver, nervous system or intestinal systems. Some symptoms can include skin irritation, stomach cramps, vomiting, nausea, diarrhea, fever, sore throat, headache, muscle and joint pain, blisters of the mouth and liver damage. Swimmers in water containing cyanobacterial toxins may suffer allergic reactions, such as asthma, eye irritation, rashes, and blisters around the mouth and nose.
Mycobacterium marinum (M. Marinum)
Infections due to M. marinum usually follows a cut or trauma while in the water or exposure of traumatized skin to aquariums or natural bodies of
water. The average incubation period (time between being in the water and showing signs of infection) was 21 days (but the range was anywhere from 5 to 270 days).
M. marinum lesions are slow growing and typically affect the elbows, knees, and backs of feet and hands. The infection can look like either nodules (image left) or shallow ulcers (image right).
M. Marinum usually requires a very long course of antbiotics–sometimes for months and can take up to a year to resolve.
In future articles, we will discuss water-related infections that public pool users are at risk for.