Amoeba & PAM
Naegleria fowleri and is a specific type of amoeba found in freshwater systems worldwide and is associated with a rare but fatal condition called primary amebic meningoencephailits (PAM). Infection in humans occurs when the amoeba enters the nasal passages and travels through the olfactory nerve to the brain. Normally, this microscopic protozoan lives in the sediment/water interface and feeds mostly on detritus (decayed organic material). When water temperatures are below 80º F (26º C), the organism resides in the sediment and does not usually pose any risk to swimmers. As the water warms above that mark, the amoeba changes into a free-swimming form that lives in the water column and is capable of causing the infection. Even in warm waters, infection is rare, but there are ways to further safeguard your health while using the local waterways. Swim in deeper clear water when possible, wear nose plugs or a scuba mask, and do not allow children to dive or play roughly in warm, shallow water areas. Although weather patterns can cause variations in water temperatures, our lakes are typically above 80 degrees from early June until early October. The City posts the beaches at Dinky Dock and Lake Baldwin Park with informational signs whenever water temperatures exceed 80 degrees.
Bacteria & Parasites
Bacterial infections ranging from ear infections, to gastrointestinal discomfort to skin infections can occur in almost any aquatic environment, even in poorly maintained pools and hot tubs. Ear infections seem to affect some people more than others. If you are prone to these infections ask your doctor to recommend an after swim ear wash and use it each time you get out of the water. (Applying a few drops of a 1:1 mix of white vinegar and rubbing alcohol to the ear canal after swimming can reduce the likelihood of a swimmer’s ear infection.) Gastrointestinal problems are usually related to ingestion of lake water, and can be caused by bacteria or protozoans. Most people know not to intentionally drink lake water, but accidentally swallowing a mouthful is not an uncommon occurrence. Generally these small amounts do not cause problems, and stomach discomfort might just as likely be from the picnic lunch as from the lake water but if you experience discomfort after swimming, a trip to the doctor may be the prudent thing to do. Skin infections from contact with natural waters are fairly uncommon, but can be severe in some cases. Do not swim if you have open cuts or scrapes, as these wounds provide easier access for harmful bacteria. Rinsing, or showering with potable water after a trip to the lake can help reduce the potential for infection. Pets and wild animals can carry parasites that are sometimes harmful to people. Typically infection occurs when a person is exposed to animal waste, either by accidentally ingesting contaminated soil or water, or by coming into contact with parasites that can burrow through bare skin, like hookworm. Preventing ingestion of lake water and wearing shoes while wading along the shore reduces the likelihood of infection.
Toxic algae refers to a group of single celled organisms known as cyanobacteria (formerly called blue-green algae). As reported in the news, some of these organisms are capable of producing a wide range of toxins ranging from liver and neurological toxins to agents that cause eye, skin (swimmer’s itch) or sinus irritations. Cyanobacteria levels in a lake are often tied to nutrient concentrations. In most cases, these are the same organisms responsible for green-looking water in our lakes. While there currently are no standards for cyanobacteria levels in place in the United States that limit recreational activities and fish consumption, Winter Park’s lakes usually have levels below what is considered potentially harmful. Swimmers should avoid water that looks excessively murky or that has a visible scum on the surface and rinse in cool tap water after swimming in the lake.
Alligators and other dangerous wildlife
Wild animals can be very beautiful and intriguing, and the desire to interact with them is often strong, and can be enhanced if the animals appear to be interested in, or unafraid of people. Intentionally interacting with wildlife, however, can be dangerous to humans and to the animals and in many cases, is against State law. Never feed wild animals of any kind. Feeding encourages them to lose their fear of humans which often leads to bites, scratches or other potentially dangerous injuries to people. Animals that become dependent on easy handouts can end up with serious health problems because the human food that replaces their natural diet rarely contains the specific nutritional content they need to remain healthy. In addition attracting animals with food to locations where people recreate increases the concentration of animal waste along shore.
Animals that become a nuisance or threat to humans usually end up being destroyed, so if you love animals and wildlife, it best to observe from a distance. In lakes, American alligators (Alligator mississippiensis) are of particular concern to many residents. To avoid confrontations always be aware of your surroundings when on or near waterways, and avoid densely overgrown areas. If you come across an alligator in the wild, you should calmly move away from the area. Feeding alligators any time of the year is illegal and dangerous. Feeding causes the animals to lose their natural fear of humans, and increases the frequency and severity of aggressive behavior.
During the months of spring, residents should be aware that alligators will become more active in area lakes as they begin mating and nesting. Alligators typically breed from April through June, and can become more aggressive during this period than they are the rest of the year. Males become increasingly territorial as the breeding season approaches, and often travel from lake to lake in search of mates. A large alligator can cover as much as twenty miles over land in a night, showing up unexpectedly in lakes that did not previously have any alligators. Most alligator aggression is channeled into threat displays intended to scare away potential rivals rather than into physical attacks. Male threat displays include raising their tail out of the water and/or bellowing (a low frequency growl that often causes the water around them to vibrate vigorously). Female alligators that are guarding nests or young often will open their mouths to warn off anyone who gets too close, and may even run out of the water with their mouths open to scare off intruders. Alligators that are cornered, or feel physically threatened, may hiss loudly. This hissing often precedes a defensive attack.
Dogs and cats are similar in size to the natural prey of alligators. Therefore, allowing pets to swim, exercise, or drink in areas that may contain alligators is a risk to their safety. In addition, do not swim with your dog as swimming dogs often attract the interest of hungry alligators.
Alligators that threaten humans or pets, or do not exhibit fear of people (do not leave an area when people approach, or actually come closer) should be reported to the Florida Fish and Wildlife Conservation Commission. State law prohibits the killing, harassing, feeding, handling, or possession of alligators. The nuisance alligator hotline number is 866-392-4286 (866-FWC-GATOR). Please be aware that alligators removed under this program are typically destroyed, and that larger animals may be killed on site for safety reasons.
Many harmless watersnakes (Nerodia spp.) are frequently confused with the less common but venomous cottonmouth or water moccasin (Agkistrodon piscivorus). While both kinds of snakes share the same semi-aquatic habitat, the concern for humans is the bite from the cottonmouth as it requires immediate medical intervention. Both can be seen basking in the sun during the hottest parts of the day, but cottonmouths do most of their foraging for food at night. They prey on fish, small turtles, juvenile alligators, birds, mammals, and lizards. Unlike water snakes that swim mostly under the water, the body of the cottonmouth is easily recognized when swimming as most of the body is above the water’s surface. Water snakes will often flee if approached on the ground or in a tree, whereas the cottonmouth tends to stand its ground and display its white open mouth as a warning to potential predators. Despite its aggressive reputation, research indicates that cottonmouths will rarely bite unless handled or stepped on. These reptiles play a critical role in controlling the population of many disease-carrying rodents and are an important part of our native Florida ecosystem. If you encounter a snake along the shore or while swimming or boating, it is best to leave it alone and give it space.
While the City of Winter Park is not heavily industrialized, there is still a lot of commercial land use within the watershed and runoff in these basins directly affects our lakes. Most of the pollution our lakes receive includes fertilizers, grass clippings, litter, oil/grease, etc. Many of these types of pollution are directly related to the use and/or disposal of these products by local residents. For example, lawn clippings should be bagged and hauled away, or applied to flowerbeds as mulch. This reduces the likelihood that they will wash into our lakes and contribute nutrients that will accelerate algal growth. Litter that isn’t properly disposed in refuse containers washes in with stormwater runoff and contributes harmful chemicals as it decomposes in the lake. While Winter Park has installed numerous stormwater retrofit structures underground to capture and remove pollution before it washes into the lake, it is still important to make sure that waste is disposed of in its proper place.
Pollution also enters our waterways from the atmosphere in rainfall. Mercury normally cycles between air, land, and water and is a natural component of earth’s crust, but about 2/3 of the mercury content in our atmosphere results from the burning of fossil fuels, mining and waste incineration. Because Florida’s climate and industry make it susceptible to mercury contamination of fish, over 300 fresh water lakes and rivers have a “limited” or “no consumption of recreationally caught fish” designation to protect human health.