Danielle M. Eriksen: Cyanobacteria is a danger to dogs

  • Danielle Eriksen’s dog, Quinn, dives into the water in pursuit of a toy. Danielle M. Eriksen

For the Monitor
Published: 8/20/2016 12:05:06 AM

My dogs love swimming. The oppressive heat this summer has found me loading them in the car many evenings to take them to a local watering hole for a quick dip. I’m not alone – there are often other people there with dogs as well. As summer nears its end and the drought continues, it’s important for dog owners to be aware – a deadly threat may be lurking in those inviting lakes and ponds.

Cyanobacteria, also known as blue-green algae, grow in any type of water, including freshwater lakes and ponds, rivers and streams, and marine water and estuaries. These bacteria are usually too small to be seen, but when conditions are favorable they sometimes form visible colonies, called harmful algal blooms, or HABs.

HABs typically occur in warm, slow-moving or standing water bodies that are rich in nutrients, such as fertilizer.

Several species of cyanobacteria produce powerful toxins, known as cyanotoxins, which can affect the nervous system, liver and skin of humans and animals.

Exposure can be caused by contact with skin and mucous membranes, ingestion or inhalation. Dogs are at greater risk of ingesting the toxins because they will drink the contaminated water and lick the algae off their fur.

Symptoms of exposure in humans can include nausea and vomiting, irritation of the skin and mucous membranes, trouble breathing, tingling in fingers and toes, and allergic responses. Studies indicate that long-term exposure may cause chronic liver and gastrointestinal problems, and possibly even cancer.

Signs of exposure in dogs can include difficulty breathing, salivation, vomiting, lethargy, excessive urination, diarrhea or seizures. Dogs have been known to die within 30 minutes of exposure.

It’s important to note that not all algae are toxic; in fact, some forms of algae are vital components to aquatic ecosystems. Likewise, not all toxic algae are visibly “blue green.”

July was the warmest month on record for the entire globe since record keeping began in 1880, and it’s no secret that New Hampshire is currently experiencing a significant drought. The heat and dryness provide prime conditions for HABs, because the bacteria prefer warmer water and the drought is causing more water to be stagnant, as inflow and outflow streams have dried up.

The Environmental Protection Agency website notes that the effects of climate change may cause harmful algal blooms to occur more often, and states that “algal blooms endanger human health, the environment and economies across the United States.”

The New Hampshire Department of Environmental Services website states that it monitors 170 freshwater public bathing beaches and 16 coastal beaches on a regular basis.

Unfortunately, my favorite spot to take my dogs isn’t one of them. At the time of this writing in mid-August, the New Hampshire Department of Environmental Services has cyanobacteria warnings on three different New Hampshire lakes. It’s a good idea to check the advisories if you regularly swim at any of these beaches.

Canine deaths from cyanotoxins are considered rare, but nevertheless, the danger is very real. One study published on the National Institutes of Health website reviewed 368 cases of cyanotoxin poisoning in dogs between 1920 and 2012, but states that, “The canine cyanotoxin poisoning events reviewed here likely represent a small fraction of cases that occur throughout the U.S. each year.”

That study then goes on to say, “The impacts of these cyanotoxins on domestic and wild animals are significantly under-recognized because many cases are misdiagnosed, few cases are biochemically confirmed, and even fewer are reported in the scientific literature or to animal health surveillance systems.”

Use caution when taking your dog swimming at any time, especially during the late summer months. Avoid water that is cloudy, has visible algae or a foul smell. If your dog inadvertently swims in questionable water, rinse it off immediately with clean water and do not allow it to lick its fur.

(Danielle M. Eriksen lives in Weare.) 

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