2016–2018 One Health Harmful Algal Bloom System (OHHABS) Report: Supplemental Tables and Figures
These tables and figures provide supplemental information not published in Surveillance for harmful algal bloom events and associated human and animal illnesses—One Health Harmful Algal Bloom System, United States, 2016-2018 (MMWR Weekly).
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OHHABS Working Group
State and federal partners in the OHHABS Working Group from 2014 to 2016 informed development of the reporting system. State partners included Arizona, Florida, Illinois, Indiana, Iowa, Kansas, Maryland, Massachusetts, Michigan, Minnesota, New York, Ohio, Oregon, South Carolina, Virginia, Washington, and Wisconsin. Federal partners included the Agency for Toxic Substances and Disease Registry (ATSDR), National Oceanic and Atmospheric Administration (NOAA), National Park Service (NPS), U.S. Environmental Protection Agency (EPA), U.S. Food and Drug Administration (FDA), and United States Geological Survey (USGS), with support from the Great Lakes Restoration Initiative (GLRI).

OHHABS development timeline
CDC and partners began development of the system in 2014 and launched the system nationally in 2016. The OHHABS Working Group was formed in January 2014, with IT development beginning in March. In May 2015, CDC finalized the definitions used to classify harmful algal bloom (HAB) events and associated cases of illness in OHHABS. The system was piloted in August 2015 before the official launch in June 2016.

States reporting HAB events
A total of 18 states adopted OHHABS and voluntarily reported 421 HAB events during 2016–2018: Alaska, Arizona, California, Connecticut, Florida, Kansas, Maryland, Michigan, Minnesota, Nevada, New York, North Carolina, Ohio, Oregon, Pennsylvania, Utah, Virginia, Wisconsin.
Thirteen states reported human cases, animal cases, or both: Alaska, California, Florida, Kansas, Michigan, Minnesota, New York, Ohio, Oregon, Pennsylvania, Utah, Virginia, Wisconsin.
Ten states reported human cases: Alaska, California, Kansas, Minnesota, New York, Ohio, Oregon, Pennsylvania, Utah, Wisconsin.
Ten state reported animal cases: California, Florida, Kansas, Michigan, Minnesota, New York, Oregon, Utah, Virginia, Wisconsin.

Reported HAB events with associated human and animal cases
States submitted 421 HAB event reports into OHHABS for 2016–2018, including 312 HAB events that did not have any associated cases. There were 73 HAB events with associated human cases, 42 with associated animal cases, and 6 with associated human and animal cases. There were 389 cases of human illnesses and at least 413 cases of animal illnesses associated with reported HAB events. The cases of animal illness were reported as 55 single cases of illness, as well as nine groups of illness. The nine groups accounted for at least 358 animal illnesses.

Reported HAB events and cases by month, 2016–2018
Two separate HAB events produced peaks of human and animal cases, as seen in this figure. During July 2016, a large HAB event resulted in 199 human cases, and in May 2018 a large HAB event caused a die-off of 300 birds.
HAB event month was assigned based on available data, using the following hierarchy: 1) bloom observation date, 2) month of bloom notification, 3) earliest date of an associated human or animal case.
Human case month is the reported illness onset date. Animal cases were assigned months based on available data, using the following hierarchy: 1) illness onset date, 2) discovery date, 3) death date.

Animal cases reported to OHHABS by month, 2016–2018
In May 2018, a bloom event resulted in a large bird die-off of 300 individuals. Animal cases were assigned months based on available data, using the following hierarchy: 1) illness onset date, 2) discovery date, 3) death date.

Classification of reported HAB events and associated cases, 2016–2018
HAB events could be classified as either suspected or confirmed; HAB-associated cases of illness could be classified as either suspected, probable, or confirmed. The majority (88%) of the 421 reported HAB events were confirmed. The majority (88%) of the 389 reported human cases were probable. The majority (81%) of 413 reported animal cases were suspected. Case classification criteria are provided in the HAB event and case definitions pdf icon[PDF – 3 pages].

Classification of reported HAB-associated animal cases, by type, 2016–2018
HAB-associated animal cases of illness could be classified as either suspected, probable, or confirmed. The majority (99%) of 319 reported wildlife cases were suspected. The majority (60%) of the 52 reported domestic pet cases were probable. The majority (81%) of the 42 reported livestock cases were probable. Case classification criteria are located in the HAB event and case definitions pdf icon[PDF – 3 pages].

Download the data: Classification of animal cases by type, 2016-2018 excel icon[XLS – 16 KB]
Reported signs and symptoms in 389 human cases of HAB-associated illness during 2016–2018 were classified primarily based on the organ system affected. “Generalized” refers to constitutional signs and symptoms such as headache, fever, or lethargy. Some signs and symptoms classified as neurologic may present in other systems (e.g., ophthalmologic). Gastrointestinal, generalized, and dermatologic were the most frequently reported categories.
Human Signs and Symptoms (n=389 cases)*
n (%)§
Human Signs and Symptoms (n=389 cases)*
Cardiopulmonary
n (%)§
41 (11)
Human Signs and Symptoms (n=389 cases)*
Cough
n (%)§
18 (5)
Human Signs and Symptoms (n=389 cases)*
Dyspnea (shortness of breath)
n (%)§
16 (4)
Human Signs and Symptoms (n=389 cases)*
Difficulty breathing
n (%)§
8 (2)
Human Signs and Symptoms (n=389 cases)*
Chest tightness
n (%)§
4 (1)
Human Signs and Symptoms (n=389 cases)*
Chest pain
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Respiratory symptoms (nonspecific)
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Respiratory irritation
n (%)§
1 (<1)
Human Signs and Symptoms (n=389 cases)*
Wheezing
n (%)§
1 (<1)
Human Signs and Symptoms (n=389 cases)*
Tachycardia (rapid heartbeat)
n (%)§
1 (<1)
Human Signs and Symptoms (n=389 cases)*
Dermatologic
n (%)§
104 (27)
Human Signs and Symptoms (n=389 cases)*
Rash
n (%)§
57 (15)
Human Signs and Symptoms (n=389 cases)*
Pruritus (itchy skin)
n (%)§
32 (8)
Human Signs and Symptoms (n=389 cases)*
Erythema (redness)
n (%)§
8 (2)
Human Signs and Symptoms (n=389 cases)*
Irritated skin
n (%)§
8 (2)
Human Signs and Symptoms (n=389 cases)*
Skin burning/pain
n (%)§
7 (2)
Human Signs and Symptoms (n=389 cases)*
Infected wound
n (%)§
4 (1)
Human Signs and Symptoms (n=389 cases)*
Skin blisters
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Itchy welts
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Bullous skin lesions (fluid filled blisters)
n (%)§
2 (1)
Human Signs and Symptoms (n=389 cases)*
Skin infection
n (%)§
1 (<1)
Human Signs and Symptoms (n=389 cases)*
Urticaria (hives)
n (%)§
1 (<1)
Human Signs and Symptoms (n=389 cases)*
Ear/Nose/Throat
n (%)§
62 (16)
Human Signs and Symptoms (n=389 cases)*
Throat, sore or pain
n (%)§
29 (7)
Human Signs and Symptoms (n=389 cases)*
Nasal, congestion (rhinitis)
n (%)§
19 (5)
Human Signs and Symptoms (n=389 cases)*
Throat, irritation
n (%)§
12 (3)
Human Signs and Symptoms (n=389 cases)*
Nasal, coryza (runny nose)
n (%)§
9 (2)
Human Signs and Symptoms (n=389 cases)*
Ears, ache or pain
n (%)§
4 (1)
Human Signs and Symptoms (n=389 cases)*
Sneezing
n (%)§
4 (1)
Human Signs and Symptoms (n=389 cases)*
Oral, sores
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Oral, numbness
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Oral, swelling
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Tongue, swollen
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Nasal inflammation
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Dysphasia (difficulty swallowing)
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Gastrointestinal
n (%)§
262 (69)
Human Signs and Symptoms (n=389 cases)*
Diarrhea
n (%)§
153 (39)
Human Signs and Symptoms (n=389 cases)*
Nausea
n (%)§
139 (36)
Human Signs and Symptoms (n=389 cases)*
Vomiting¶
n (%)§
116 (30)
Human Signs and Symptoms (n=389 cases)*
Abdominal pain (tenderness)
n (%)§
75 (19)
Human Signs and Symptoms (n=389 cases)*
Abdominal cramps
n (%)§
27 (7)
Human Signs and Symptoms (n=389 cases)*
Bloody stools
n (%)§
4 (1)
Human Signs and Symptoms (n=389 cases)*
Gas/bloating
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Generalized
n (%)§
169 (43)
Human Signs and Symptoms (n=389 cases)*
Headache
n (%)§
105 (27)
Human Signs and Symptoms (n=389 cases)*
Fever
n (%)§
51 (13)
Human Signs and Symptoms (n=389 cases)*
Fatigue
n (%)§
29 (7)
Human Signs and Symptoms (n=389 cases)*
Anorexia (loss of appetite)
n (%)§
16 (4)
Human Signs and Symptoms (n=389 cases)*
Lethargy (lack of energy, tiredness)
n (%)§
16 (4)
Human Signs and Symptoms (n=389 cases)*
Chills
n (%)§
13 (3)
Human Signs and Symptoms (n=389 cases)*
Pain (general)
n (%)§
10 (3)
Human Signs and Symptoms (n=389 cases)*
Body ache
n (%)§
8 (2)
Human Signs and Symptoms (n=389 cases)*
Malaise (general discomfort)
n (%)§
7 (2)
Human Signs and Symptoms (n=389 cases)*
Night sweats
n (%)§
5 (1)
Human Signs and Symptoms (n=389 cases)*
Faintness (lightheadedness)
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Pallor
n (%)§
2 (1)
Human Signs and Symptoms (n=389 cases)*
Hot flash(es)
n (%)§
2 (1)
Human Signs and Symptoms (n=389 cases)*
Flushing (face or body)
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Sweating
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Flu-like symptoms
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Genitourinary
n (%)§
6 (2)
Human Signs and Symptoms (n=389 cases)*
Dysuria (pain with urination)
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Dark urine
n (%)§
2 (1)
Human Signs and Symptoms (n=389 cases)*
Hematuria (blood in urine)
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Musculoskeletal
n (%)§
13 (3)
Human Signs and Symptoms (n=389 cases)*
Muscle pain
n (%)§
10 (3)
Human Signs and Symptoms (n=389 cases)*
Arthralgia (joint pain)
n (%)§
5 (1)
Human Signs and Symptoms (n=389 cases)*
Muscle fatigue
n (%)§
2 (1)
Human Signs and Symptoms (n=389 cases)*
Backache
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Muscle cramps
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Neurologic
n (%)§
56 (14)
Human Signs and Symptoms (n=389 cases)*
Dizziness
n (%)§
34 (9)
Human Signs and Symptoms (n=389 cases)*
Paresthesia (tingling sensation)
n (%)§
17 (4)
Human Signs and Symptoms (n=389 cases)*
Weakness
n (%)§
15 (4)
Human Signs and Symptoms (n=389 cases)*
Ataxia (loss of coordination)
n (%)§
5 (1)
Human Signs and Symptoms (n=389 cases)*
Temperature reversal (hot-cold reversal)
n (%)§
5 (1)
Human Signs and Symptoms (n=389 cases)*
Confusion
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Neurological symptoms (nonspecific)
n (%)§
2 (1)
Human Signs and Symptoms (n=389 cases)*
Seizures
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Ascending paralysis
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Ophthalmologic
n (%)§
30 (8)
Human Signs and Symptoms (n=389 cases)*
Eye irritation
n (%)§
14 (4)
Human Signs and Symptoms (n=389 cases)*
Blurred vision
n (%)§
5 (1)
Human Signs and Symptoms (n=389 cases)*
Eye burning
n (%)§
4 (1)
Human Signs and Symptoms (n=389 cases)*
Conjunctivitis (pinkeye)
n (%)§
4 (1)
Human Signs and Symptoms (n=389 cases)*
Periorbital edema (swelling)
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Eye pain
n (%)§
3 (1)
Human Signs and Symptoms (n=389 cases)*
Eye redness
n (%)§
2 (1)
Human Signs and Symptoms (n=389 cases)*
Watery eyes
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Eye symptoms (nonspecific)
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Other
n (%)§
30 (8)
Human Signs and Symptoms (n=389 cases)*
Other
n (%)§
28 (7)
Human Signs and Symptoms (n=389 cases)*
Dry mouth
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Anaphylaxis
n (%)§
1(<1)
Human Signs and Symptoms (n=389 cases)*
Unknown
n (%)§
9 (2)
∗ 67% of cases still experienced symptoms at the time of interview.
§ Percentages may exceed 100% because multiple options could be selected.
¶ Includes one report of hematemesis (bloody vomitus).
Reported signs in 92 animal cases of HAB-associated illness during 2016–2018 were classified primarily based on the organ system affected. “Generalized” refers to constitutional signs such as weakness, lethargy, or anorexia. Some signs classified as neurologic may present in other systems (e.g., ophthalmologic).
Animal Signs*
n (%)§
Animal Signs*
Cardiopulmonary
n (%)§
7 (8)
Animal Signs*
Shock
n (%)§
1 (1)
Animal Signs*
Hypotension
n (%)§
1 (1)
Animal Signs*
Labored breathing
n (%)§
1 (1)
Animal Signs*
Wheezing
n (%)§
1 (1)
Animal Signs*
Cyanosis/pale mucous membrane
n (%)§
1 (1)
Animal Signs*
Respiratory arrest
n (%)§
1 (1)
Animal Signs*
Dermatologic
n (%)§
2 (2)
Animal Signs*
Itching
n (%)§
2 (2)
Animal Signs*
Ear/Nose/Throat
n (%)§
1 (1)
Animal Signs*
Ear irritation
n (%)§
1 (1)
Animal Signs*
Gastrointestinal
n (%)§
50 (54)
Animal Signs*
Diarrhea
n (%)§
26 (28)
Animal Signs*
Vomiting
n (%)§
24 (26)
Animal Signs*
Liver failure
n (%)§
2 (2)
Animal Signs*
Painful abdomen (on palpitation)
n (%)§
1 (1)
Animal Signs*
Jaundice
n (%)§
1 (1)
Animal Signs*
Tucked abdomen (arched back)
n (%)§
1 (1)
Animal Signs*
Generalized
n (%)§
59 (64)
Animal Signs*
Lethargy
n (%)§
15 (16)
Animal Signs*
Anorexia (loss of appetite)
n (%)§
10 (11)
Animal Signs*
Weakness
n (%)§
6 (7)
Animal Signs*
Collapse (unable to stand)
n (%)§
4 (4)
Animal Signs*
Dehydration (refusing water)
n (%)§
2 (2)
Animal Signs*
Stumbling
n (%)§
1 (1)
Animal Signs*
Whining or abnormal vocalization
n (%)§
1 (1)
Animal Signs*
Hematologic
n (%)§
1 (1)
Animal Signs*
Unexplained bleeding
n (%)§
1 (1)
Animal Signs*
Neurologic
n (%)§
13 (14)
Animal Signs*
Seizure/Convulsions
n (%)§
6 (7)
Animal Signs*
Ataxia (stumbling, loss of balance)
n (%)§
3 (3)
Animal Signs*
Behavior change
n (%)§
2 (2)
Animal Signs*
Paralysis
n (%)§
2 (2)
Animal Signs*
Opisthotonos (severe hyperextension)
n (%)§
1 (1)
Animal Signs*
Stupor (decreased consciousness, unresponsiveness)
n (%)§
1 (1)
Animal Signs*
Other
n (%)§
3 (3)
Animal Signs*
Other
n (%)§
3 (3)
∗ Summarized for the subset of reports with data available.
§ Percentages may exceed 100% because multiple options could be selected.
Download the data: Animal HAB-associated illnesses signs excel icon[XLS – 19 KB]