Watch For Toxic Blue-Green Algae
US - Among the problems arising from this summer’s extended heat wave is the potential for toxic blue-green algae to show up in lakes and ponds.
26 July 2011
4 minute read
“Blue-green algae is typically only a problem during the hottest part of the summer,” said Kansas State University veterinarian Larry Hollis. “It appears that we are seeing an increase in cases this year because of the extended heat period and/or lack of additional rain.”
As in much of the country, July temperatures in Kansas have soared near or above 100 degrees for numerous consecutive days.
The algae are toxic to humans, as well as animals. Livestock species often serve as sentinels for human illness, said Mr Hollis, who specialises in beef cattle care with K-State Research and Extension.
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.
Most of the samples the diagnostic lab has tested so far this summer have had BGA present, sometimes in very high numbers, Mr Hollis said.
Cyanobacteria, also known as blue-green algae, are prominent in Kansas waters. And, under certain conditions, harmful algal blooms (also called HABs) produce toxins that pose a health risk to people and animals, according to the Kansas Department of Health and Environment. The toxins have been responsible for several dogs’ death.
These blooms are an emerging public health issue in Kansas. In 2010, public health advisories or warnings were issued for public waters in seven counties, due to HABs.
So far in 2011, the KDHE has received reports of at least two cases of human illness, due to contact with HABs. An interactive by-county Kansas map displays the lakes currently implicated by HAB reports.
Cyanobacteria and their toxins in fresh waters have been associated with human and animal illness in at least 36 US states. The greatest risk of adverse human health effects is after exposure through ingestion or inhalation of water droplets and cyanobacterial cells during recreational activities, such as swimming and water skiing. Skin contact with high concentrations of cyanobacteria, independent of the level of toxins, may also cause adverse health effects.
Human health effects can vary and are dependent upon the type of toxin and route of exposure. The most common complaints after recreational exposure include vomiting, diarrhea, skin rashes, eye irritation and respiratory symptoms.
Cyanobacterial toxins are classified in two categories: hepatotoxins and neurotoxins. The most common in Kansas is Mycrocystis species, which produce hepatotoxins. But, blooms of Anabaena spp., which produce neurotoxins, have been identified recently.
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 an animal survives the initial phase of liver failure, neurological dysfunction that’s secondary to liver failure is possible. 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.
No specific antidote is available, according to KDHE. Handlers should bathe animals’ contaminated skin, but wear protective clothing and gloves to prevent their own skin contact. Livestock producers and pet owners also should contact their veterinarian if they think an animal has been exposed to BGA. The prognosis is poor for animals that develop severe liver failure.
The basis for diagnosis in animals is usually clinical signs and the presence of cyanobacteria in water the animal has contacted. 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.
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