Veterinarian Outreach Letter from Interagency Working Group on Harmful Algal Bloom Related Illnesses

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To: California Veterinarians

From: Interagency Working Group on Harmful Algal Bloom Related Illnesses

The purpose of this letter is to bring attention to the upcoming harmful algal bloom (HAB) season and to offer assistance for responding to HAB-related illnesses in animals.  We are also requesting your assistance with reporting HAB-related animal illnesses to the state centralized system shown below.

The occurrence of HABs appears to be increasing in inland waters of California, which has led to an increase in the public’s concern regarding potential health impacts to humans and animals, particularly dogs.  HABs are responsible for illnesses and deaths of dogs, livestock, and wildlife every year in California.  In 2017, state and local agencies posted 141 public health alerts at waterbodies throughout California. Reported HAB-related incidents last year included 25 domestic animal deaths, numerous fish and wildlife incidents, and 8 human incidents. Most blooms occur in spring to fall, but can begin earlier or continue year-round in some locations. The first indication of a HAB-related hazard in a local waterbody often originates from animal owners and veterinarians.

Resources are available to assist veterinarians to respond to incidents of suspected HAB-related illness in animals.  The California Water Boards provide limited funding for confirmatory testing of HAB-related poisonings in canines, and can assist with HAB identification and early response in suspected exposure areas.  State or local agencies can post warning signs at hazardous waterbodies to prevent additional animal poisonings.

Please use one of the following options to report HAB-related animal illnesses and mortalities (suspected or confirmed) to the centralized state database.  Your reports will alert us of your need for assistance and will expedite state efforts to track the frequency, distribution and impacts of HABs in California:

Reporting a HAB-related animal incident through any of the options above will trigger a multi-agency coordination effort consisting of the following:

  • The California Water Boards will contact your office to coordinate the available assistance for confirmatory testing in canines. They will also gather information on the suspected exposure area in order to investigate the associated waterbody and coordinate with other government agencies involved in HAB response.
  • The California Environmental Health Tracking Program (CEHTP) at the California Department of Public Health (CDPH) or the Office of Environmental Health Hazard Assessment (OEHHA) will contact your office to request additional health information on the affected animal. CDPH is implementing California’s HAB-related human and animal illness reporting to the Centers for Disease Control (CDC) One Health Harmful Algal Bloom System (OHHABS).
  • If the reported illness involves fish or wildlife, OEHHA will inform the California Department of Fish and Wildlife (CDFW) and assist in collecting the relevant data. 

Veterinarians are encouraged to review the factsheet from the California Cyanobacteria and Harmful Algal Bloom (CCHAB) Network that provides technical information on assessing exposure history, evaluating clinical signs, pursuing diagnosis and confirmatory testing, and patient management in potential HAB-related animal illnesses.  The CDC provides a HABs animal safety poster designed for animal owners.  Symptoms of HAB-related illness in animals are also available from the CDC.  An up-to-date map of known HAB occurrences in California, as well as other important HAB-related information, are available through the California HABs Portal.  These resources focus on inland HABs occurring in freshwater, estuarine and lagoon environments.  For information on HABs in coastal marine areas, refer to CDPH’s Marine Biotoxin Monitoring Program and CalHABMAP.

Resources for responding to HABs are extremely limited throughout the state. Our agencies are attempting to coordinate and support a HAB response involving multiple agencies at several levels of government in order to protect the public and the environment from the adverse impacts of HABs. Additionally, data collection and tracking are valuable tools for estimating the impact of HABs and identifying efforts that would help to address HABs statewide. 

Please contact the staff listed below with feedback or questions relating to these plans.

CEHTP: Susan Paulukonis (; 510-620-3667)

OEHHA: Beckye Stanton (; 916-322-2088) and Reggie Linville (; 916-327-7336)

State Water Resources Control Board: Marisa VanDyke (; 916-322-8431) and Ali Dunn (; 916-319-8458);

CDFW: Stella McMillin (; 916-358-2954) and Krysta Rogers (; 916-358-1662)