Harmful Algal Blooms: Cyanobacteria: Cyanobacteria and CyanoHABs Facts | CDC HSB

http://www.cdc.gov/hab/cyanobacteria/facts.htm[10/31/2010 8:44:05 AM]

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NCEH › HABs › Cyanobacteria › Cyanobacteria and CyanoHABs Facts

FACTS ABOUT CYANOBACTERIA AND

CYANOBACTERIAL HARMFUL ALGAL

BLOOMS

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Cyanobacteria (blue-green algae)

Cyanobacterial blooms and how they form

What a cyanobacterial bloom looks like

Cyanobacterial harmful algal blooms (CyanoHABs)

Other effects of fresh-water CyanoHABs

Species of cyanobacteria that form CyanoHABs in fresh water

Cyanotoxins

How you could be exposed to CyanoHABs and cyanotoxins

Types of illnesses people and animals can get from exposure

to CyanoHABs

Testing for cyanobacterial toxins

How to protect yourself, your family, and your pets from

exposure to CyanoHABs

How to treat people or animals that have been exposed to

cyanobacterial toxins

How to help reduce the occurrence of CyanoHABs

How to get more information about cyanobacteria

References

Cyanobacteria (blue-green algae)

Cyanobacteria, also known as blue-green algae, grow in any type of

water and are photosynthetic (use sunlight to create food and

support life). Cyanobacteria live in terrestrial, fresh, brackish, or

marine water. They usually are too small to be seen, but sometimes

can form visible colonies, called an algal bloom. Cyanobacteria

have been found among the oldest fossils on earth and are one of

the largest groups of bacteria. Cyanobacteria have been linked to

human and animal illnesses around the world, including North and

South America, Africa, Australia, Europe, Scandinavia, and China.

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Cyanobacterial blooms and how they form

Cyanobacterial blooms (a kind of algal bloom) occur when

organisms that are normally present grow exuberantly. Within a few

days, an bloom of cyanobacteria can cause clear water to become

cloudy. The blooms usually float to the surface and can be many

inches thick, especially near the shoreline. Cyanobacterial blooms

can form in warm, slow-moving waters that are rich in nutrients

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such as fertilizer runoff or septic tank overflows. Blooms can occur

at any time, but most often occur in late summer or early fall.

They can occur in marine, estuarine, and fresh waters, but the

blooms of greatest concern are the ones that occur in fresh water,

such as drinking water reservoirs or recreational waters.

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What a cyanobacterial bloom looks like

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.

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Cyanobacterial harmful algal blooms (CyanoHABs)

CyanoHABs are algae blooms that threaten people, animals, or the

environment. They are dangerous for many reasons:

Dense CyanoHABs can block sunlight and use up all the

oxygen in the water, killing other plants and animals.

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.

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Other effects of fresh-water CyanoHABs

CyanoHABs can make drinking water smell and taste bad.

They can make recreational areas unpleasant.

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Species of cyanobacteria that form CyanoHABs in

fresh water

Microcystis aeruginosa

Anabaena circinalis

Anabaena flos-aquae

Aphanizomenon flos-aquae

Cylindrospermopsis raciborskii.

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Cyanotoxins

Cyanotoxins are a diverse group of chemical substances that are

categorized by their specific toxic effects as follows:

Neurotoxins affect the nervous system.
Harmful Algal Blooms: Cyanobacteria: Cyanobacteria and CyanoHABs Facts | CDC HSB

http://www.cdc.gov/hab/cyanobacteria/facts.htm[10/31/2010 8:44:05 AM]

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.

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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 jetskiing or boating.

Inhaling aerosols when watering lawns, irrigating golfcourses, etc. with pond water.

Using cyanobacteria-based dietary supplements that are

contaminated with microcystins.

Receiving dialysis (this has been documented only in Brazil).

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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
Harmful Algal Blooms: Cyanobacteria: Cyanobacteria and CyanoHABs Facts | CDC HSB

http://www.cdc.gov/hab/cyanobacteria/facts.htm[10/31/2010 8:44:05 AM]

death. People may have numb lips, tingling fingers

and toes, or they may feel dizzy.

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Testing for cyanobacterial toxins

Most of the toxins require specialized testing that can take

weeks.

Some kits are available to test for microcystins on site.

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How to protect yourself, your family, and your pets

from exposure to CyanoHABs

Don’t swim, water ski, or boat in areas where the water is

discolored or where you see foam, scum, or mats of algae

on the water.

If you do swim in water that might have a CyanoHAB, rinse

off with fresh water as soon as possible.

Don’t let pets or livestock swim in or drink from areas where

the water is discolored or where you see foam, scum, or

mats of algae on the water.

If pets (especially dogs) swim in scummy water, rinse them

off immediately—do not let them lick the algae (and toxins)

off their fur.

Don’t irrigate lawns or golf courses with pond water that

looks scummy or smells bad.

Report any "musty" smell or taste in your drinking water to

your local water utility.

Respect any water-body closures announced by local public

health authorities.

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How to treat people or animals that have been

exposed to cyanobacterial toxins

Get medical treatment right away if you think you, your pet,

or your livestock might have been poisoned by

cyanobacterial toxins.

Remove people from exposure and give them supportive

treatment.

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How to help reduce the occurrence of CyanoHABs

Reduce nutrient loading of local ponds and lakes by using

only the recommended amounts of fertilizers and pesticides

on your yard.

Properly maintain your household septic system.

Maintain a buffer of natural vegetation around ponds and

lakes to filter incoming water.

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How to get more information about cyanobacteria

Federal

Centers for Disease Control and Prevention
Harmful Algal Blooms: Cyanobacteria: Cyanobacteria and CyanoHABs Facts | CDC HSB

http://www.cdc.gov/hab/cyanobacteria/facts.htm[10/31/2010 8:44:05 AM]

(CDC)

Harmful Algal Blooms (HABs) site

This site defines HABs; describes CDC’s HABsrelated activities; and provides links to data,

publications, and other HABs resources.

Cyanobacteria site

This site defines cyanobacteria; describes CDC’s

cyanobacteria-related activities; and provides links to

data, publications, and other cyanobacteria

resources.

Environmental Protection Agency (EPA)

Drinking Water Contaminant Candidate List site

[external link]

This site provides information about EPA’s list of

contaminants that are not regulated, occur in public

water systems, and may require regulation under the

Safe Drinking Water Act. Algae that can be harmful

are on this list.

International

State of Queensland Australia, HAB site [external link]

This site describes the state’s plans and procedures for

agency responding to HABs.

World Health Organization [external link]

This site provides links to drinking and recreational water

quality, including the impacts of cyanobacteria and

cyanobacterial toxins.

States

North Carolina Department of Health and Human

Services

Occupational and Environmental Epidemiology

program, HABs Site [external link]

This site gives an overview of North Carolina’s HAB

program and provides links to the state’s HABrelated surveillance, research, and education

activities.

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References

1. Carmichael WW, Beasley V, Bunner DL, Eloff JN, Falconer

IR, Gorham PR, et al. Naming of cyclic heptapeptide toxins

of cyanobacteria (blue-green algae). Toxicon. 1988;26:971-

3.

2. Carmichael, WW, Falconer IR. Diseases related to

freshwater blue-green algal toxins, and control measures. P.

187-209. In: Falconer I R (ed.). Algal Toxins in Seafood and

Drinking Water. London: Academic Press. 1993: pp187-209.

3. Dahlem AM, Hassan AS, Swanson SP, Carmichael WW,

Beasley VR. A model system for studying the bioavailability

of intestinally administered microcystin-LR, a hepatotoxic

peptide from the cyanobacterium Microcystis aeruginosa.
Harmful Algal Blooms: Cyanobacteria: Cyanobacteria and CyanoHABs Facts | CDC HSB

http://www.cdc.gov/hab/cyanobacteria/facts.htm[10/31/2010 8:44:05 AM]

Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta, GA 30333, U.S.A.

Tel: (404) 639-3311 • CDC Contact Center: 800-CDC-INFO • 888-232-6348 (TTY)

Department of Health

and Human Services

Pharmacol. Toxicol. 1989;64:177-81.

4. Falconer, IR, Beresford AM, Runnegar MT. 1983. Evidence

of liver damage by toxin from a bloom of blue-green algae,

Microcystis aeruginosa. Med J Aust. 1983;1: 511-4.

5. Hawkins PR, Chandrasena NR, Jones GJ, Humpage AR,

Falconer IR. Isolation and toxicity of Cylindrospermopsis

raciborskii from an ornamental lake. Toxicon. 1997;35:341-

346.

6. Humpage A R, Hardy SJ, Moore EJ, Froscio SM, Falconer

IR. Microcystins (cyanobacterial toxins) in drinking water

enhance the growth of aberrant crypt foci in the mouse

colon. J Toxicol Environ Health, Part A. 2000;61:155-65.

7. Kirpenko YA, Sirenko LA, KirpenkoNI. Some aspects

concerning remote after-effects of blue-green algal toxin

impact on warm-blooded animals. In: Carmichael WW (ed.).

The Water Environment, Algal Toxins and Health. New

York: Plenum, 1981: pp257-69.

8. Soong F S, Maynard E, Kirke K, Luke C. Illness associated

with blue-green algae. Med J Aust. 1992;156:67.

9. Turner PC, Gammie AJ, Hollinrake K, Codd GA (1990).

Pneumonia associated with contact with cyanobacteria. Br

Med J. 1990;300:1440-1.

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