#swimmersitch

[higginslakesliceintime]

Swimmer’s Itch Control Under Way

What is Simmer’s Itch and how do you fix it?

Swimmer’s Itch has been a persistent problem on northern Michigan lakes for a number of years. In the past it has been treated with copper sulfate treatments, a method is now frowned upon because of its potential long term environmental impacts. There are now two proposed control programs under way – one championed by the Simmer’s Itch Partnership chaired by Jim Vondale who is now also president of HLPOA and one championed by Gerrish Township under the leadership of Frank Homola, Gerrish Township Supervisor.

The contractor for the first approach is SICon, LLC lead by Dr. Curtis Blankespoor who has a doctorate in parasitology from Cornell and who has been studying Swimmer’s since 1988 and who is now a professor at Calvin College, and by Ronald Reimink, a biologist with experience with Swimmer’s Itch and who is one of the founders of SICon. The total cost of their program is $225,000 per year over three years.

The second contractor is Steven Sendek, Northpoint Fisheries Management, LLC, and Dr. Mark Luttenton. Phd. Their proposed full program for 2015 has a cost of $82,000.

The Biology

Birds, specifically Mergansers, are the “definitive” hosts for the flat worm parasite, called avian schistosomes, that causes swimmers itch.  Avian schistosomes pass their eggs in the feces of their host. When these eggs pass into the lake, they hatch into larvae within an hour which drop to the bottom. Some find an intermediate host, a specific snail, where they reproduce asexually and then produce second larvae called a cercariae. As many as a thousand leave the snail, looking for a new avian host. Swimmer’s itch occurs when the cercariae accidentally penetrate into humans where they die. Reddened spots occur within hours and last for several days.

Back in October, Dr. Blankespoor made a presentation to an ad hoc group interested in Swimmer’s Itch. Here is a quick presentation on the biology based on material he provided.

Parasite: Trichobilharzia Stagnicola

Miracidia

Hatch fro eggs

Free-living

Lifespan approximately 48 hours

Negatively geotactic (drop to the bottom of the lake)

50 eggs per duck feces

Cercariae

Free-living

Life span approximately 48 hours

Positively geotactic (rise to surface)

Definitive Host: Common Mergansers

Life span up to 12 years

Migratory – summer breeders in Michigan

After hatch year, birds prospect for nests for one season

Males leave shortly after mating

Average brood of 9-12 eggs

Very wary birds with a low mortality

Daily range of 10 miles on the water

Defecate 20+ times per day. Feces are 5 grams

Hatch year birds have the highest parasite loads

Nests typically high in trees as much as a mile from the lake (per Cornell Ornithological Lab)

Intermediate Host: Stagnicola Emrginata

12-16 month life span – June through August of the following year

Eggs laid in spring, hatch in early June

·Prefer hard, sandy lake bottoms

Daily range of 100 feet

Infection rate less than 2%

Latency of infection 1 month

Infected snails shed 2000 cercariae per day

According to Cornell Ornithology Lab web site, “Common Mergansers are streamlined ducks that float gracefully down small rivers or shallow shorelines. The males are striking with clean white bodies, dark green heads, and a slender, serrated red bill.

The elegant gray-bodied females have rich, cinnamon heads with a short crest. In summer, look for them leading ducklings from eddy to eddy along streams or standing on a flat rock in the middle of the current. These large ducks nest in hollow trees; in winter they form flocks on larger bodies of water.

In northern forests Common Mergansers will take up residence in nest boxes near lakes or rivers, as long as the boxes are large with a large opening

SICon’s Program

SICon’s “Comprehensive Simmer’s Itch Control Program” proposes a 3-year effort which combines educational outreach, scientific research, and bird and snail control. The control program involves capturing and removing the parasite’s definitive host. Adult hosts are trapped, treated with an “antihelmintic drug” to kill any existing adult parasites living in its body, and/or relocating the birds to waterways where there are no receptive snail intermediate hosts. The total cost would be $225,000, per year or a total of $675,000.

The first year’s cost includes the following:

Off season preparation ($15,000)

Avian Shistosome Species Assessment (#30,000) – fee waived in 2015.

Bird Control Program ($195,000)

Snail Removal Project ($20,000) – fee waived in 2015

Educational Activities and Outreach Program ($10,000)

Boat Rental $5,000)

Lodging provided by client

Treatment of Nesting Sites and Eggs (Additional service at $1000 per nest, $1000 per egg)

The objective of the bird control program is to determine the location of common merganser nesting sites on or near the lake and to reduce the number of eggs deposited in the lake. The proposal states, “When nest prospecting and nesting, common mergansers exhibit persistent and stereotypic behaviors. Careful observations of these behaviors can lead on to the location of a female’s nesting site. GPS coordinates with video verification of all nests will be provided… Beginning around May 1, weekly bird surveys of Higgins Lake will be conducted and every effort will be made to trap and relocate as many after-hatch-year (AHY) common merganser birds and their broods as possible. Trapping methods will include SICon, LLC’s modified drive trap and other devices or methods developed during the off-season research and development phase….”

Because snails sustain their infections over the winter, the proposal points out that a significant reduction of the infection rate of snails will not be occur until 2017. They also state that it is “unrealistic to expect the elimination of all swimmer’s itch cases, as a complete eradication of avian schistosomes in an aquatic ecosystem is impossible.”

Northpoint (Sendek) Program

Northpoint’s “Comprehensive Action Plan to Address Swimmer’s Itch on Higgins Lake” focuses on actions to minimize the presence of common Merganser’s on the lake. Actions include hazing, and harassing birds to prevent them from frequenting the lake and a lethal take of up to twenty-five birds. Harassments will occur from ice-out to May 22 or until broods are noted.  

The proposal also includes the destruction of up to twenty five nests.  To simplify nest treatment, their objective is to create nesting sites through the use of nesting boxes at prime locations around the lake. The boxes would be sealed on May 22. Birds killed will be evaluated for the presence of avian schistosome. The boxes will be made by Gerrish staff and installed and monitored by Northpoint.

The program also includes assessment of snail infection rates, abundance of cercariae in the water, and merganser fecal samples. It also calls for the development of rapid assessment tools and methods to track host snail population genetics.

What’s Actually Being Done?

The Higgins Lake Swimmer’s Itch Organization (HLSIO) has been formed with a board to manage the Comprehensive Swimmer’s Itch Program. The Organization has filed for 501(c) (3) status and according to Jim Vondale has had its non-profit status approved by the IRS. Board members are: President Jim Vondale, Vice President Ken Dennings, Treasurer Ed Nellist, Secretary Bill Carey (Carey and Jaskowski), Neil Cooley (owner of Fred’s), Dale McDonald (The McDonald Group), and Bob Schneider (Chair Roscommon County Commission.) The HLPOA board has approved $15,000 from HLPOA funds to support the swimmer’s itch effort by HLSIO. Another $35,000 has been raised and more fund raising is expected. The remainder will have to be raised privately. According to Vondale, SICon has agreed to proceed event though the full funding is not yet in place.

Gerrish Township at this point is proceeding with the duck killing and harassment portion of the Northpoint proposal using $5,000 of its own funds and a $23,000 grant from the Higgins Lake Foundation. According to Jim Vondale, the Gerrish permit requires any ducks killed to be turned over to SICon for evaluation. He is hopeful that the Gerrish effort will not interfere with what SICon is doing and would like to see cooperation between the two efforts.

To the extent Gerrish and Lyon Townships get involved in long term funding, the most likely approach would be through special assessments on a per property basis. At issue is whether this would be assessed to lakefront owners only or town wide. Gerrish has 5,031 properties and Lyon has 3,435; Gerrish has about 900 lakefront properties and Lyon 359. If both participated and the cost was spread across all properties, the three year SICon proposal would coast $27 per year per property. The full Northpoint program would cost $82,000 per year or $10 per property per year.

Housing is being sought for the SICon group, especially for the period from May 15 to the end of July. Additionally, there is at least one board position open on the HLSIO board, possibly more. There is no representation from the north shore of the lake, so any suggestions for good candidates should be sent to one of the existing board members.

Some of us remember that Jamie Saxton (MSU grad student) and a couple of different co-researchers who stayed in Pinewoods for a couple of years, doing some of the original studies of the snails and problems with swimmers' itch. Clearly it's increasing, and it's terribly difficult to cure.  Some understandably have concerns that the SICOM program is trodding a path already traveled.

On the other hand, nothing has been tried before at the scale that is being proposed. Part of the response is that while a reduction in the number of swimmer’s itch cases is the most direct method of assessment of our control program, it is also the most costly and difficult. One would need trained medical professionals and a scientific approach to the assessment rather than the anecdotal evidence that is often quite bias. According to Curtis Blankespoor, “what has been documented, however, is that for the 3 years we worked on Glen Lake there was a significant reduction in both the number of common mergansers present on the lake and the prevalence of infection in snails.”

My personal feeling is that it’s too early to discount either approach and am happy to see them both proceeding. Hopefully, the two groups will find a way to cooperate.  A minor downside is that if successful, it makes it hard to attribute the source of the success.