Fact Sheet: Blue-Green Algae/Cyanobacteria Harmful Algal Bloom (HABs) Physician Reference

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Blue-Green Algae/Cyanobacteria Harmful Algal Bloom (HABs) Physician Reference

From the Ohio Department of Health Bureau of Environmental Health – Health Assessment Section – “To protect and improve the health of all Ohioans”

The Public Health Issue:

This summer Ohio’s local health departments, local physician offices, Poison Control Centers and the state health department have received reports of illness from people who have claimed to have had contact with HAB-contaminated water. Several of Ohio’s inland lakes have experienced cyanobacteria blue-green algae blooms, commonly referred to as Harmful Algal Blooms (HABs). Depending on the genera, water conditions, and other factors, neurotoxins, hepatotoxins, cytotoxins, dermatotoxins and gastrointestinal toxins can be produced by cyanobacteria. These toxins are released to the water as the bacteria die. Water samples from various Ohio lakes have detected the presence of microcystin, anatoxin-a, cylindrospermopsin and saxitoxin. Both humans and animals can experience illness from exposure to these toxins during recreational activities and other water uses.

Exposure and Clinical Presentation:

Route of Exposure	Symptoms/Signs	Time to symptom onset*	Differential Diagnosis
Swallowing water contaminated with cyanobacteria or toxins	Hepatotoxins (microcystins, cylindrospermopsin) Elevated ALT, GGT Gastroenteritis Acute hepatitis Kidney damage Malaise Headache Anorexia	Minutes to hours	Other hepatotoxin poisoning, other microbial infections/toxins
Swallowing water contaminated with cyanobacteria or toxins	Neurotoxins (anatoxin-a, anatoxin-a[s], saxitoxin) Paresthesia Tremor Fasciculations Hypersalivation Diarrhea Ataxia Motor weakness Respiratory & muscular paralysis	Minutes to hours	Pesticide poisoning, other toxin poisoning
Skin contact with water contaminated with cyanobacteria or toxins or contact with animals contaminated with cyanobacteria	Dermal toxins (Lyngbyatoxins, lipopolysaccharide endotoxins) Rash, hives Skin blistering Allergic reactions	Minutes to hours	Other dermal allergens. non-allergic urticaria, photosensitivity reactions
Inhaling aerosolized droplets contaminated with cyanobacteria or toxins	Upper respiratory irritation Rhinitis Possibe allergic reaction	Unknown, but likely an acute reaction	Other airborne allergens, upper respiratory infection, flu
*Symptom onset times are primarily extrapolations from laboratory animal data and events.

Diagnosis and Lab Testing:

Currently there is no laboratory diagnostic testing which can confirm the presence of cyanotoxins in human clinical specimens. In the absence of laboratory confirmation, presumptive diagnosis can be made based upon exposure history, clinical signs and symptoms, and ruling out other diagnoses. In cases where exposure to hepatotoxins is suspected, a standard liver panel is recommended (AST (SGOT), ALT, ALP, GGT, albumin and bilirubin). Tests for ruling out other diagnoses should also be performed.

Case Definition

CDC case definition summary for selected toxins (for complete description see CDC Proposed Case Definitions for Algal Toxin-related Diseases)

Suspect Case Exposure to water with a confirmed algal bloom AND onset of associated signs and symptoms within a reasonable time after exposure AND without identification of another cause of illness.
Probable Case Meets criteria for Suspect Case AND there is laboratory documentation of a HAB toxin(s) in the water.
Confirmed Case Meets criteria for a Probable Case combined with professional judgment based on medical review.

Freshwater Cyanotoxins	Type of Toxin	Causative organism	Vector
Anatoxin-a	Neurotoxin	Anabaena spp. Aphanizomenon spp. Planktothrix spp.	Contaminated fresh water
Anatoxin-a(s)	Neurotoxin	Anabaena flos-aquae	Contaminated fresh water
Cylindrospermopsin	Hepatotoxin	Cylindrospermopsis raciborskii, Aphanizomenon ovalisporum	Contaminated fresh water and possibly fish
Lyngbyatoxin	Dermal toxin	Lyngbya spp.	Contaminated fresh or marine waters
Microcystins	Hepatotoxin	M. aeruginosa Anabaena spp. Planktothrix spp.	Contaminated fresh water
Saxitoxins	Neurotoxin	Anabaena circinalis Lyngbya wollei	Contaminated fresh water

Treatment and Patient Management:

Symptomatic, supportive care. There are currently no known antidotes for exposures to the group of toxins associated with cyanobacteria. Follow-up laboratory testing as indicated.

Patient Education

Community education outreach efforts are currently being pursued by the state agencies involved addressing Ohio HABs. Please refer to the following links for more information regarding Harmful Algal Blooms:

HAB Case Reporting Requirements

Pursuant to Ohio Administrative Code (OAC) Chapter 3701-3-02 and the ODH Infectious Disease Control Manual healthcare providers are required to submit reports of human illness related to exposure to HABs to the local health district where the ill individual resides. Reports are to be made under Class C – “waterborne disease outbreaks; report single cases of toxin poisoning associated with exposure to water with a confirmed algal bloom by the end of the next business day to the local public health department where the patient resides.”

WHO must report? Healthcare providers (physicians, hospitals, infection control professionals, local public health providers) with knowledge of a case or suspect case of HAB exposure and illness are required to report.
WHAT must be reported? Healthcare providers must submit the HAB-related human illness form to the local health district where the ill individual resides.
WHEN must a report be made? Class C – must be sent by the end of the next business day to the local public health department where the patient resides.
WHERE must the report be made? Healthcare providers should send the case information the local health jurisdiction in which the case or suspected case was believed to take place.
A listing of local health departments may be found at: odh.ohio.gov

ODH, with assistance from the Centers for Disease Control and Prevention, has developed case definitions and the following human illness reporting form for HAB-related illnesses:

HAB-related human illness report:
www.odh.ohio.gov

Animal Illness:
Reports of suspected domestic animal illness associated with exposure to HAB should be reported to the Local Health District. Local health districts receiving reports from veterinarians should contact the ODH Zoonotic Disease Program (ZDP) at 614-752-1029, select option two (2). Completed animal illness report forms can be faxed to the ODH ZDP at 614-644-1057.