An article in the newspaper a few weeks ago noted there had been an outbreak of cyanobacteria on a New Hampshire lake, which was closed to swimming for a week.
I originally wrote about this topic a few years ago when it came to my attention that toxic algae can be fatal to dogs, other animals and people. Even though most of us have been unaware of this problem, the first instance of cyanobacteria in New Hampshire was as long ago as 1960. Because it can be extremely dangerous, and the heat and humidity of summer create the bacteria season, this seems like a good time to reprise part of that column:
An email alert from the "Whole Dog Journal" (www.whole-dog-journal.com) read: "Freshwater ponds, lakes and streams could be deadly to your water dog if they contain toxins borne by blue-green algae [Cyanobacteria].
"If the water where your dog swims looks cloudy, with a green or blue-green cast, you should suspect a dangerous overgrowth of blue-green algae, and prevent your dog from ingesting the water.
"Whole Dog Journal has confirmed a report from a Michigan dog owner whose nine-month-old Border Collie died shortly after swimming in a pond near Fenton, Missouri."
The article went on to say, "The emergency vet told the dog's owner that he had recently seen other dogs die of blue-green algae toxicity - a condition that can kill pets, livestock, and people who drink the contaminated water.
'Had I ever heard of the danger of blue-green algae, I never would have allowed my dogs to swim in that or any other pond; I would have bought a pool,' the owner told Whole Dog Journal."
When the man contacted Michigan's Department of Natural Resources looking for more information about the algae, the article says "he was told that the toxic blooms rarely occur except in late summer, and not to either panic or panic other people.
'Had someone else panicked, we wouldn't be having this conversation right now,' the grieving owner told the state representative.
"Dog owners should be aware that toxic algae blooms usually occur in late summer or early fall, but can occur at any time. They can occur in marine, estuarine, and (especially) fresh water.
The latter are of the greatest concern to dog owners, as dogs are commonly taken to ponds, lakes, and reservoirs in the summer for recreation, exercise, and cooling - and they routinely drink the water. Some of these algae blooms look like foam, scum, or mats on the surface of the water.
The blooms can be blue, bright green, brown, or red ('red tide' is perhaps the best-known so-called 'harmful algal bloom') - but some blooms may not affect the appearance of the water. The water may or may not smell bad. As a further difficulty to dog owners trying to protect their dogs, not all algal blooms are toxic!"
After I read this article, I contacted the N.H. Department of Environmental Services at the time to ask whether New Hampshire dog owners need to be aware of this.
We sure do! A few years ago, a horse died after drinking toxic water from a pond in Pittsfield. In fact, New Hampshire was the first state in the nation to issue public beach advisories. This is a worldwide problem. In 1998, the World Health Organization published a drinking water guideline value for one cyanotoxin.
According to the current DES website: "Cyanobacteria occur naturally in waterbodies throughout the world. However, when excess nutrients enter the water, cyanobacteria cell concentration may increase.
Once a bloom or surface scum forms, cyanobacteria can present a potential health risk to humans and pets. DES advises against swimming in any waters experiencing a cyanobacteria bloom, and pets and children especially should not make contact with the water."
Anyone who suspects a cyanobacteria bloom should call the DES cyanobacteria hotline at 419-9229 and, if possible, collect a water sample with a clean bottle or zip-type plastic bag while wearing gloves, or at least take a photo of the bloom.
The DES says the sample should be labeled with the location, date, time and contact information and placed on ice until it can be transferred to the DES Limnology Center for analysis.
The bottom line is we need to be extremely cautious. Before taking your dog (or children) swimming, you can check for updates on current advisories that may be in effect on the DES website: www2.des.state.nh.us/Advisories/Beaches.
Gail Fisher, author of "The Thinking Dog," runs All Dogs Gym & Inn in Manchester. To suggest a topic for this column, email firstname.lastname@example.org or write c/o All Dogs Gym, 505 Sheffield Road, Manchester, NH 03103. You'll find past columns on her website.