Amanda Teixeira
Blue-green algae can be life-threatening for dogs. Read here about the health risk that blue-green algae pose for animals and humans, how you can recognize infested waters and blue-green algae poisoning in your dog, and how you can protect your dog from blue-green algae.
On a walk, dog owners allow their three dogs to go swimming in a pond. Less than fifteen minutes later, a dog suffers severe seizures. The owners immediately take him to the veterinary clinic. Once there, the second of the three dogs begins to show signs of a seizure. Shortly thereafter, the third dog also falls ill and the liver begins to fail. All three dogs die the very next day. The reason for this tragic incident: the pond in which the dogs were bathing was infested with toxic blue-green algae.
What happened in North Carolina in the USA has also happened in Germany: 20 dogs have been poisoned by blue-green algae in Lake Tegel in the past five years, 17 of them have died, as the BZ reports. In 2021, a dog died as a result of blue-green algae poisoning.
What are blue-green algae and when are they toxic?
Blue-green algae are bacteria with a blue-greenish color. Hence the scientific name cyanobacteria. They are the oldest organisms on earth and can be found in every ecosystem. They produce oxygen and use it to supply the creatures in the water.
Not all blue-green algae are toxic: “Only some of the cyanobacteria species produce poisons (toxins), which at certain concentrations can affect the health of humans and warm-blooded animals risk cannot be ruled out,” says the website of the Baden-Württemberg State Institute for the Environment.
It becomes particularly problematic at high temperatures or when large quantities of agricultural waste products end up in water bodies. Because that favors the mass reproduction of blue-green algae. When it blooms, usually in August, the blue-green algae float on the surface of the water like a green carpet. If there is a heavy infestation with blue-green algae, the toxic effect is very high and very dangerous, especially for animals and children.
What health risk do blue-green algae pose for animals and humans?
Blue-green algae are toxic. Bathing in heavily overgrown waters is harmful to animals, children and adults.
Adults who swallow too much contaminated water while bathing can get away with irritation of the skin, mucous membranes and conjunctiva, as well as diarrhea and vomiting. In the worst case, however, it can lead to fever, liver damage, paralysis of the respiratory muscles or even damage to the nervous system. Small children who swallow too much contaminated water are at risk of death!
Animals are also at risk: Dogs that eat the remains of the blue-green algae washed ashore or even just lick them off their fur can be fatal, as the current cases in the USA and the cases in Berlin last year show.
Which bodies of water are affected?
When temperatures rise, the blue-green algae bloom increases rapidly. The individual federal states are responsible for monitoring bathing water. They control the waters and provide information online about relevant bans or issue warnings. In addition, bathers are informed directly at the waters with warnings about bathing bans.
How do I recognize a body of water with blue-green algae?
Relying solely on waterside warnings is not enough. Because the waters are only checked once a month. At high temperatures, however, the quality of the water can change very quickly. Therefore, pay attention to signs that indicate that a body of water is heavily infested with blue-green algae:
- Streaks and carpets in the water that shimmer blue-green are a clear sign of contamination by blue-green algae.
- Another sign of blue-green algae can also be a bad smell of rotten eggs, manure, and ammonia.
- If the infestation is so severe that you can no longer see your feet standing knee-deep in water, it can be very dangerous for animals and humans.
How do I protect my dog from blue-green algae poisoning?
There is only one sure way to protect your dog from poisoning with blue-green algae: If you have discovered blue-green algae in a body of water, then do not let your dog bathe there under any circumstances! This is the only way you can guarantee that your dog will not poison itself. For untroubled bathing pleasure, we also recommend:
- If you visit a body of water regularly on your walk, then always keep the responsible authority up to date on the water quality.
- It is essential to observe bathing bans and do not let your dog bathe in waters that have warnings about blue-green algae.
- Avoid bathing in places where there are many waterfowl.
- Put the dog on a leash in infested areas (especially warm, shallow, calm areas of lakes, ponds, and streams that get long exposure to sunlight).
- If the dog has already entered infested water, make sure that it does not lick its fur and paws.
- If your dog has bathed in a body of water during the walk, rinse it off thoroughly at home. This will prevent blue-green algae from getting stuck in the fur.
How do I recognize blue-green algae poisoning in dogs?
Many dog owners whose dogs suddenly become very ill and even die do not usually attribute this to bathing in a lake infested with blue-green algae. Rather, a severe infection or other causes are suspected. So watch out for the following symptoms in your dog:
- Lethargy, weakness and disorientation
- Pale mucous membranes
- Excessive salivation and tear production
- Muscle tremors, muscle rigidity, paralysis, seizures
- shortness of breath
- vomiting and diarrhea
- jaundice
- shock and unconsciousness
If you notice these symptoms after a bathing tour not long ago, then poisoning with blue-green algae is likely.
Blue-green algae poisoning is also very dangerous for cats, horses and birds. Once the animals have poisoned themselves, the course of the disease is dramatic and ends fatally in many cases.