HAB-related Illness Tracking in California

What are HAB-related Illnesses?

Cyanobacteria (also known as blue-green algae) and algae occur in freshwater and estuarine waterbodies. When these organisms pose a risk to humans, animals, and the environment, they are referred to as harmful algal blooms (HABs).  Humans and animals can become sick after eating or contacting cyanobacteria, water contaminated with cyanotoxins, or algal mats.  Cyanotoxins may also accumulate in fish and shellfish. Symptoms may occur within minutes or days following exposure and may include:

  • irritation of skin, ears, eyes, nose, or throat
  • abnormal breathing (coughing, wheezing, asthma-like symptoms)
  • vomiting, diarrhea, abdominal pain,
  • headaches, agitation, weakness
  • seizures and death (in animals)

How can I report a HAB-related Illnesses?

Please report any suspected HAB or potential HAB-related illness by any of these methods: 

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How can I protect myself, my family, and my pets from HAB-related illness?

Learn more on the CA HABs Portal:

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Who is tracking HAB-related Illnesses in California?

The Interagency HAB-related Illness Workgroup has investigated and tracked potential HAB-related illnesses in humans and animals throughout California. The workgroup includes staff from the Office of Environmental Health Hazard Assessment, the State Water Resources Control Board, the California Department of Public Health (CDPH), and the California Department of Fish and Wildlife. All potential illnesses undergo further evaluation of the available environmental and health related information, and those considered HAB-related are included in final summaries (as noted below). The information presented on this web page can be downloaded as a factsheet (PDF).

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How many HAB-related Illnesses have been reported for California?

In 2018 - 2019, CDPH has reported 41 HAB-related cases from California to the Centers for Disease Control and Prevention’s (CDC) One Health Harmful Algal Bloom System (OHHABS). A summary of HAB-related illness by year and type of organism impacted is provided in the table below.

Table 1. Total Reports to OHHABS 2018 - 2019

Organism

2018

2019

Total to date (2018 & 2019)

Dog

4

5

9

Livestock

0

0

0

Wildlife

3

2

5

Fish

4

8

12

Human

8

7

15

TOTAL

19

22

41

In which counties did these reported HAB-related illnesses occur?

The map below displays the counties in which HAB-related illnesses from California (reported to OHHABS) have occurred for both years combined. Illnesses are grouped by human only, human and animal (domestic or wild), or animal only.

California map of HAB-related Illnesses

How are HAB-related illnesses being tracked across the United States?

The CDC’s OHHABS is a voluntary reporting system available to state and territorial public health departments and their designated environmental health or animal health partners. It collects data on individual human and animal cases of illnesses from HAB-associated exposures, as well as environmental data about HABs. OHHABS is an example of One Health surveillance. One Health is an approach that recognizes that human, animal, and environmental health are interconnected, and that human health, animal health, and environmental health communities can more effectively address many linked health challenges by working together.


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