Should you avoid the water?

A fisherman’s photos of a nasty case of swimmer’s itch, allegedly contracted at Cape Henlopen State Park, are getting a lot of attention on social media.

Floyd Morton, a Georgetown mechanic, was wading in the Delaware Bay between the park’s fishing pier and The Point on the evening of Friday, Sept. 22. The 49-year-old had been in and out of the water, using a net to catch bait, for about ten minutes when he felt a familiar tingling sensation on his feet and ankles.

“I’ve had [swimmer’s itch] before so I knew what it felt like. I went and wiped myself down with some antiseptic,” Morton said. “But it was too late.”

Morton had contracted swimmer's itch, also known as clam digger’s itch, or more properly as cercarial dermatitis.

The parasite

According to the U.S. Centers for Disease Control and Prevention, cercarial dermatitis is caused by a parasite and is unrelated to environmental pollution.

The parasite has a complex life cycle and only affects humans at a certain stage.

The adult parasite lives in the blood of birds like ducks, geese and gulls and some mammals, such as muskrats and raccoons. The adults produce eggs that are then passed in the feces of infected animals and often land and hatch in the water. The hatched larvae are microscopic and often overpowered by the tide or other factors, which is why you’re more likely to encounter them in still water.

The hatched larvae seek out a certain species of snail, which they infect and grow in. Eventually, the parasite leaves the snail and searches for a bird or mammal in which to continue its lifecycle.

It’s at this point that the parasite can infect humans - when they mistake us for a suitable host. The parasite will burrow into human skin, causing a rash and discomfort, but then die very quickly.

You can contract cercariae dermatitis across the globe, in salt and fresh water. In fact, it occurs more often in fresh water. It cannot be contracted from properly chlorinated swimming pools.

To avoid the parasite, the CDC recommends you don’t feed birds in or around swimming areas and don’t go in or near marshy areas without proper protection, i.e., boots or waders.

Professor Jonathan Cohen at the University of Delaware’s College of Earth, Ocean and Environment said there may be factors that increase the prevalence of the parasite at certain times and in certain places.

“The fall migration of birds is thought to increase presence of [the parasite] that causes swimmer's itch,” Cohen said. “Low tide, calm water and sun may also be related.”

So you’ve got swimmer’s itch

It’s important to rinse off as soon as possible after leaving a body of water, regardless of how your skin feels. There are many things in the water that could cause a reaction.

“Quite a few marine organisms can cause skin irritation to swimmers,” said Cohen.

If you’re in the water and you feel a tingling, itching or burning sensation on your skin, get out and rinse off immediately and then towel yourself dry to prevent any further contraction. However, keep in mind that it’s possible that one could contract cercariae dermatitis and not notice any symptoms for several days.

The tell-tale cercariae dermatitis rash usually appears within 12 hours. The small, reddish pimples may develop into small blisters, and they will likely be very itchy. Avoid scratching, as that could lead to an infection. Swimmer’s itch usually runs its course in a few days, but can last up to two weeks.

According to the CDC, most cases of swimmer's itch do not require medical attention. Over-the-counter corticosteroid cream, cool compresses and Epsom salt baths are usually enough to soothe symptoms.  Cercariae dermatitis is not contagious.

How concerned should you be?

“We have a problem in this area,” Morton said. “Since 1999, this is the third time I’ve been infected.”

Each of Morton’s swimmer’s itch incidents occurred in the bay between the pier and The Point at Cape Henlopen during the fall season. After his most recent problem, he posted pictures of his pocked feet and legs to a Facebook page he runs, Delaware Brethren of the Coast. That post went somewhat viral, garnering over 700,000 views.

For unknown reasons, Facebook removed the post a few days after it went up. However, Morton continued to photograph his symptoms and create new posts, and people lamented their own experiences with parasite.

“People say I’m making sensationalist claims, but people need to know about this. The park needs to post permanent signs, big signs,” Morton said.

Other people in the fishing community disagreed.

“I’m not worried about it,” said guru Rich King. “I’m more worried about chiggers.”

Cape Henlopen State Park Manager Grant Melville has been with the park for two summer seasons and said Morton’s was the first case of cercariae dermatitis he’d heard of there. Park officials have since posted a single sign warning swimmers about the incident.

In October 1991, about 30 students on a field trip to Cape Henlopen State Park developed symptoms of cercariae dermatitis after wading in the water. The Delaware Division of Public Health conducted a study to assess the outbreak and merely recommended to park officials that they advise people in the area to wear protective clothing in the water for the next two months.

According to the CDC, many factors must be present for swimmer’s itch to become a problem in any one area, and there is no way to know how long the area may be unsafe. However, larvae usually don’t survive any longer than 24 hours after leaving the snail.