Skip all navigation Skip to page navigation

DHHS Home | A-Z Site Map | Divisions | About Us | Contacts

NC Department of Health and Human Services
NC Division of Public Health
N.C. Public Health Home


Protecting Children & Dogs

Cyanobacteria (blue-green algae) are naturally-occurring microscopic algae that often grow in fresh bodies of water such as lakes, ponds and canals. Like plants, they can use the sun as an energy source. Small numbers of cyanobacteria can explosively grow into large numbers very quickly. This rapid increase is called a bloom. The bloom can become harmful to people, pets, livestock, and aquatic plants and animals by producing toxins, shading light, and clogging gills in fish. (Learn more about cyanobacteria.)

Toxins produced by cyanobacteria can affect the kidneys, gastrointestinal tract, liver, and nervous system of people, pets, livestock and other animals. Children and dogs are the most vulnerable to the effects of cyanobacterial toxins. Dogs are especially susceptible to cyanotoxins that attack the nervous system. Deaths of dogs associated with cyanobacteria have been identified in North Carolina. Inadvertently, dogs can also alert us to possible adverse human health effects due to harmful algal blooms.

By nature, dogs often play and wade in shallow areas of a pond or lake where algal blooms tend to concentrate due to wind and water currents, and where the toxins can become concentrated. Dogs usually become exposed to the toxins by drinking bloom waters or eating the algae. Algal toxins can be lethal to a dog.

Young children also play and wade in the shallow areas of ponds and lakes, and are exposed to toxins by ingesting bloom waters containing toxin. Due to their size, children may have adverse health effects from smaller amounts of toxin than would affect an adult. No reports of adverse health effects in children associated with cyanobacterial blooms have been identified in North Carolina. That may be because people generally avoid bloom waters, while many animals do not.

N.C. DHHS recommends the following steps to safeguard pets and children from harmful cyanobacterial (blue-green algal) blooms:

  • Keep children and pets away from waters that appear discolored or scummy.
  • Do not handle or touch large accumulations ("scums" or mats) of algae.
  • Do not water ski or jet ski over algal mats.
  • Do not use scummy water for cleaning or irrigation.
  • If you accidently come into contact with an algal bloom, wash thoroughly.
  • If your pet appears to stumble, stagger, or collapse after being in a pond, lake or river, seek veterinary care immediately.
  • If your child appears ill after being in waters containing a bloom, seek medical care immediately.
  • If you are unsure whether or not a bloom is present, it is best to stay out of the water.

For Additional Information