Cattle cooling off in ponds can ingest toxic blue-green algae.
Cattle cooling off in ponds can ingest toxic blue-green algae.

We’ve been very hot and dry where I live in eastern Kansas, in addition to similar conditions across the Midwest and Great Plains. As I drive out to my horses I pass several cattle pastures with cattle up to their ears in farm ponds to cool off. I’ve been filling horse tanks every day because our ponds have receded and algae blooms are covering the water.

Blue-green algae (BGA) can be toxic to cattle, other animals and humans. Larry Hollis, DVM, Kansas State University, says, “Blue-green algae is typically only a problem during the hottest part of the summer. It appears that we are seeing an increase in cases this year because of the extended heat period and/or lack of additional rain.”

Cyanobacteria, also known as blue-green algae, grow in any type of water and are photosynthetic. Some cyanobacterial blooms can look like foam, scum, or mats on the surface of fresh water lakes and ponds. The blooms can be blue, bright green, brown, or red and may look like paint floating on the water. Some blooms may not affect the appearance of the water. As algae in a cyanobacterial bloom die, the water may smell bad.

Getting cyanobacteria on the skin may give people a rash, hives, or skin blisters (especially on the lips and under swimsuits). Inhaling water droplets from irrigation or water-related recreational activities can cause runny eyes and nose, a sore throat, asthma-like symptoms, or allergic reactions. Swallowing water that has cyanobacterial toxins in it can cause acute, severe gastroenteritis (including diarrhea and vomiting), liver toxicity, kidney toxicity and neurotoxicity. In dogs, the neurotoxins can cause salivation and other neurologic symptoms, including weakness, staggering, difficulty breathing, convulsions, and death. People may have numb lips, tingling fingers and toes, or they may feel dizzy.

Some animals become ill after swimming in contaminated waters and grooming their coat after it dries. The first signs of animals’ blue-green algae poisoning usually occur within 30 minutes of exposure and include vomiting and diarrhea. These symptoms are followed by progressively worsening signs of liver failure, such as anorexia, lethargy and depression. Jaundice, abdominal swelling and tenderness in the abdominal area may also occur. Blood values of liver enzymes are typically very high.

If a neurotoxin is involved, neurological signs can occur minutes to hours following exposure and may include tremors, salivation, seizures, weakness and respiratory paralysis. Acute deaths are possible if the toxin dose is high.

Livestock species often serve as sentinels for human illness, says Hollis.

So look out for yourself, your family as they take part in water activities, and livestock and pets as they venture to the pond for a drink.

Report cases when you can
The conditions have prompted the Kansas state public health veterinarian and the Kansas State University Veterinary Diagnostic Laboratory to issue a joint request to Kansas veterinarians, asking that they report suspected illness in animals due to BGA. Such reports go to the Kansas Department of Health and Environment Epidemiology Hotline at 1-877-427-7317, available 24 hours a day, 7 days a week.

Identification of cyanobacteria in water, stomach contents and hair coat samples is available at the Kansas State Veterinary Diagnostic Laboratory (KSVDL) in Manhattan. The laboratory can be contacted at 785-532-5678 to coordinate sample and specimen submission.

More information, including current public health advisories, warnings and instructions on how to report a suspected case of blue-green algae poisoning, is available at the KDHE website