Human Health and HABs

FAQs for Human Health in Recreational Waters

How can I or my family be exposed to HABs?

lake swimming

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?

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:

man fly fishing

  • 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;
  • agitation;
  • 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

Resources for Medical Professionals

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.

RESOURCES:

For general information on HABs please refer to the HABs FAQ webpage

(07/29/2024)