Cyanobacteria
the common name for cyanobacteria is blue-green algae. However, cyanobacteria are related more closely
to bacteria than to algae.
Scientists have called cyanobacteria the origin of plants, and have credited cyanobacteria with providing nitrogen
fertilizer for rice and beans.
Freshwater CyanoHABs can use up the oxygen and block the sunlight that other organisms need to live. They also can
produce powerful toxins that affect the brain and liver of animals and humans. Because of concerns about CyanoHABs,
which can grow in drinking water and recreational water, the U.S. Environmental Protection Agency (EPA) has added
cyanobacteria to its Drinking Water Contaminant Candidate List. This list identifies organisms and toxins that EPA
considers to be priorities for investigation.
Humans can be exposed to cyanobacterial toxins by drinking water that contains the toxins, swimming in water that
contains high concentrations of cyanobacterial cells, or breathing air that contains cyanobacterial cells or toxins (while
watering a lawn with contaminated water, for example).
Health effects associated with exposure to high concentrations of cyanobacterial toxins include:
stomach and intestinal illness;
trouble breathing;
allergic responses;
skin irritation;
liver damage; and
neurotoxic reactions, such as tingling fingers and toes.
Scientists are exploring the human health effects associated with long-term exposure to low levels of cyanobacterial
toxins. Some studies have suggested that such exposure could be associated with chronic illnesses, such as liver
cancer and digestive-system cancer.
http://www.cdc.gov/hab/cyanobacteria/about.htm
Some cyanobacteria that can form CyanoHABs produce toxins that are among the most powerful natural poisons
known. These toxins have no known antidotes. CyanoHABs can make people, their pets, and other animals sick. Often,
the first sign that an HAB exists is a sick dog that has been swimming in an algae-filled pond. Children are at higher risk
than adults for illness from CyanoHABs because they weigh less and can get a relatively larger dose of toxin.
Cyanotoxins Cyanotoxins are a diverse group of chemical substances that are categorized by their specific toxic effects
as follows: Neurotoxins affect the nervous system. Anatoxin-a Anatoxin-a(s) Saxitoxin Neosaxitoxin Hepatotoxins
affect the liver. Microcystins Nodularins Cylindrospermopsin Tumor promoters are chemicals that can increase tumor
growth. Microcystins Lipopolysaccharides are chemicals that can affect the gastrointestinal system. See Table 1
[opens in new window] for a list of cyanotoxins and their specific toxic mechanisms, their effects, the symptoms they
cause, and treatments for poisoning.
How you could be exposed to CyanoHABs and cyanotoxins Drinking water that comes from a lake or reservoir with a
CyanoHAB. Drinking untreated water. Engaging in recreational activities in waters with CyanoHABs. Inhaling aerosols
from water-related activities such as jet-skiing or boating. Inhaling aerosols when watering lawns, irrigating
golf-courses, etc. with pond water. Using cyanobacteria-based dietary supplements that are contaminated with
microcystins. Receiving dialysis (this has been documented only in Brazil).
Types of illnesses people and animals can get from exposure to CyanoHABs
Getting it 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 (i.e., increased serum levels of liver enzymes). Symptoms of liver poisoning may takes hours or days to
show up in people or animals. Symptoms include abdominal pain, diarrhea, and vomiting.
Kidney toxicity.
Neurotoxicity. These symptoms can appear within 15 to 20 minutes after exposure. 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.
http://www.cdc.gov/hab/cyanobacteria/facts.htm#exposure