Human Health and HABs
- Frequently Asked Questions (FAQs) for Human Health in Recreational Waters and Drinking Water
- Resources for Medical Professionals
How can I or my family be exposed to HABs?
Human exposure to HABs (cyanobacteria and/or associated cyanotoxins) most commonly occurs through ingestion or skin contact with contaminated water. Inhalation of spray or mist coming off water with high cyanotoxin concentrations may also contribute to exposure during activities such as water-or jet-skiing. Cyanotoxins may also accumulate in fish and shellfish. Children are considered more susceptible to effects from cyanotoxin than adults.
How can I keep myself and my family safe from HABs?
- Check if a waterbody has a reported bloom by checking the HAB Reports Map, contacting the waterbody manager, and looking for posted advisory signs.
- Check to see if the water has a scum or is discolored.
- Practice Healthy Water Habits at your local lake, river, or stream!
- Report any suspected HAB or potential HAB-related illness.
What are signs of possible exposure to cyanobacterial or cyanotoxins in people?
The following symptoms may occur within 48 hours of exposure to a waterbody with a suspected or confirmed algal bloom:
- sore throat or congestion;
- coughing, wheezing, or difficulty breathing;
- red, or itchy skin, or a rash;
- skin blisters or hives;
- earache or irritated eyes;
- diarrhea or vomiting;
- headache; and/or,
- abdominal pain.
If people show symptoms of cyanotoxin and/or cyanobacteria exposure after contact with water, or with scums or mats of algae, they should receive immediate medical attention. Additional resources are available from the Centers for Disease Control and Prevention (CDC), and by contacting the California Poison Control Center (1-800-222-1222). See the HAB-related Illness Tracking webpage for information on previously reported human illnesses related to HABs in California.
Can cyanobacteria impact people even if cyanotoxins are not detected in a water body?
Yes, cyanobacteria themselves can adversely impact people and animals, regardless of the presence of cyanotoxins. Exposure of skin to elevated amounts of cyanobacteria cells (such as in discolored water, scum, or mats) has been associated with dermal effects such as skin rashes, ear and eye infections, and gastrointestinal distress. Avoid water that has a scum or is discolored and practice Healthy Water Habits
Medical professionals can be alerted to look for signs of cyanotoxin exposure in other patients, especially if these facilities are located near water where HABs may be present. Medical professionals should be encouraged to report any suspected or confirmed cases of cyanotoxin exposure to the local health department and to the HAB Portal bloom incident form. See the HAB-related Illness Tracking webpage for information on previously reported human illnesses related to HABs in California.
- CDPH HAB Information for Physicians
- HAB-related Illness Tracking factsheet
- 2019 Bloom Season Outreach Letter to Local Health Officers and Environmental Health Directors from Interagency Working Group on Harmful Algal Bloom Related Illnesses (July 2019)
- 2018 Bloom Season Outreach Letter to Local Health Officers from Interagency Working Group on Harmful Algal Bloom Related Illnesses (April 2018)
- CDC Physician Reference Card
- USEPA Health Effects from Cyanotoxins
- USEPA HABs Infographics to educate the public on HAB basics (customized for California)