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).
Note: To save these images, left-click, hold, and drag each image to the folder where you want to save it.
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.

Download the data: Reported HAB events with associated human and animal cases [XLS – 15 KB]
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.

Download the data: Reported HAB event and case occurrence by month, 2016-2018 [XLS – 15 KB]
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 – 3 pages].

Download the data: Classification of reported HAB events and cases, 2016-2018 [XLS – 16 KB]
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 – 3 pages].

Download the data: Classification of animal cases by type, 2016-2018 [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)*
Human Signs and Symptoms (n=389 cases)*
Human Signs and Symptoms (n=389 cases)*
n (%)§
n (%)§
n (%)§
Cardiopulmonary
Human Signs and Symptoms (n=389 cases)*
Cardiopulmonary
41 (11)
n (%)§
41 (11)
Cough
Human Signs and Symptoms (n=389 cases)*
Cough
18 (5)
n (%)§
18 (5)
Dyspnea (shortness of breath)
Human Signs and Symptoms (n=389 cases)*
Dyspnea (shortness of breath)
16 (4)
n (%)§
16 (4)
Difficulty breathing
Human Signs and Symptoms (n=389 cases)*
Difficulty breathing
8 (2)
n (%)§
8 (2)
Chest tightness
Human Signs and Symptoms (n=389 cases)*
Chest tightness
4 (1)
n (%)§
4 (1)
Chest pain
Human Signs and Symptoms (n=389 cases)*
Chest pain
3 (1)
n (%)§
3 (1)
Respiratory symptoms (nonspecific)
Human Signs and Symptoms (n=389 cases)*
Respiratory symptoms (nonspecific)
3 (1)
n (%)§
3 (1)
Respiratory irritation
Human Signs and Symptoms (n=389 cases)*
Respiratory irritation
1 (<1)
n (%)§
1 (<1)
Wheezing
Human Signs and Symptoms (n=389 cases)*
Wheezing
1 (<1)
n (%)§
1 (<1)
Tachycardia (rapid heartbeat)
Human Signs and Symptoms (n=389 cases)*
Tachycardia (rapid heartbeat)
1 (<1)
n (%)§
1 (<1)
Dermatologic
Human Signs and Symptoms (n=389 cases)*
Dermatologic
104 (27)
n (%)§
104 (27)
Rash
Human Signs and Symptoms (n=389 cases)*
Rash
57 (15)
n (%)§
57 (15)
Pruritus (itchy skin)
Human Signs and Symptoms (n=389 cases)*
Pruritus (itchy skin)
32 (8)
n (%)§
32 (8)
Erythema (redness)
Human Signs and Symptoms (n=389 cases)*
Erythema (redness)
8 (2)
n (%)§
8 (2)
Irritated skin
Human Signs and Symptoms (n=389 cases)*
Irritated skin
8 (2)
n (%)§
8 (2)
Skin burning/pain
Human Signs and Symptoms (n=389 cases)*
Skin burning/pain
7 (2)
n (%)§
7 (2)
Infected wound
Human Signs and Symptoms (n=389 cases)*
Infected wound
4 (1)
n (%)§
4 (1)
Skin blisters
Human Signs and Symptoms (n=389 cases)*
Skin blisters
3 (1)
n (%)§
3 (1)
Itchy welts
Human Signs and Symptoms (n=389 cases)*
Itchy welts
3 (1)
n (%)§
3 (1)
Bullous skin lesions (fluid filled blisters)
Human Signs and Symptoms (n=389 cases)*
Bullous skin lesions (fluid filled blisters)
2 (1)
n (%)§
2 (1)
Skin infection
Human Signs and Symptoms (n=389 cases)*
Skin infection
1 (<1)
n (%)§
1 (<1)
Urticaria (hives)
Human Signs and Symptoms (n=389 cases)*
Urticaria (hives)
1 (<1)
n (%)§
1 (<1)
Ear/Nose/Throat
Human Signs and Symptoms (n=389 cases)*
Ear/Nose/Throat
62 (16)
n (%)§
62 (16)
Throat, sore or pain
Human Signs and Symptoms (n=389 cases)*
Throat, sore or pain
29 (7)
n (%)§
29 (7)
Nasal, congestion (rhinitis)
Human Signs and Symptoms (n=389 cases)*
Nasal, congestion (rhinitis)
19 (5)
n (%)§
19 (5)
Throat, irritation
Human Signs and Symptoms (n=389 cases)*
Throat, irritation
12 (3)
n (%)§
12 (3)
Nasal, coryza (runny nose)
Human Signs and Symptoms (n=389 cases)*
Nasal, coryza (runny nose)
9 (2)
n (%)§
9 (2)
Ears, ache or pain
Human Signs and Symptoms (n=389 cases)*
Ears, ache or pain
4 (1)
n (%)§
4 (1)
Sneezing
Human Signs and Symptoms (n=389 cases)*
Sneezing
4 (1)
n (%)§
4 (1)
Oral, sores
Human Signs and Symptoms (n=389 cases)*
Oral, sores
3 (1)
n (%)§
3 (1)
Oral, numbness
Human Signs and Symptoms (n=389 cases)*
Oral, numbness
1(<1)
n (%)§
1(<1)
Oral, swelling
Human Signs and Symptoms (n=389 cases)*
Oral, swelling
1(<1)
n (%)§
1(<1)
Tongue, swollen
Human Signs and Symptoms (n=389 cases)*
Tongue, swollen
1(<1)
n (%)§
1(<1)
Nasal inflammation
Human Signs and Symptoms (n=389 cases)*
Nasal inflammation
1(<1)
n (%)§
1(<1)
Dysphasia (difficulty swallowing)
Human Signs and Symptoms (n=389 cases)*
Dysphasia (difficulty swallowing)
1(<1)
n (%)§
1(<1)
Gastrointestinal
Human Signs and Symptoms (n=389 cases)*
Gastrointestinal
262 (69)
n (%)§
262 (69)
Diarrhea
Human Signs and Symptoms (n=389 cases)*
Diarrhea
153 (39)
n (%)§
153 (39)
Nausea
Human Signs and Symptoms (n=389 cases)*
Nausea
139 (36)
n (%)§
139 (36)
Vomiting¶
Human Signs and Symptoms (n=389 cases)*
Vomiting¶
116 (30)
n (%)§
116 (30)
Abdominal pain (tenderness)
Human Signs and Symptoms (n=389 cases)*
Abdominal pain (tenderness)
75 (19)
n (%)§
75 (19)
Abdominal cramps
Human Signs and Symptoms (n=389 cases)*
Abdominal cramps
27 (7)
n (%)§
27 (7)
Bloody stools
Human Signs and Symptoms (n=389 cases)*
Bloody stools
4 (1)
n (%)§
4 (1)
Gas/bloating
Human Signs and Symptoms (n=389 cases)*
Gas/bloating
3 (1)
n (%)§
3 (1)
Generalized
Human Signs and Symptoms (n=389 cases)*
Generalized
169 (43)
n (%)§
169 (43)
Headache
Human Signs and Symptoms (n=389 cases)*
Headache
105 (27)
n (%)§
105 (27)
Fever
Human Signs and Symptoms (n=389 cases)*
Fever
51 (13)
n (%)§
51 (13)
Fatigue
Human Signs and Symptoms (n=389 cases)*
Fatigue
29 (7)
n (%)§
29 (7)
Anorexia (loss of appetite)
Human Signs and Symptoms (n=389 cases)*
Anorexia (loss of appetite)
16 (4)
n (%)§
16 (4)
Lethargy (lack of energy, tiredness)
Human Signs and Symptoms (n=389 cases)*
Lethargy (lack of energy, tiredness)
16 (4)
n (%)§
16 (4)
Chills
Human Signs and Symptoms (n=389 cases)*
Chills
13 (3)
n (%)§
13 (3)
Pain (general)
Human Signs and Symptoms (n=389 cases)*
Pain (general)
10 (3)
n (%)§
10 (3)
Body ache
Human Signs and Symptoms (n=389 cases)*
Body ache
8 (2)
n (%)§
8 (2)
Malaise (general discomfort)
Human Signs and Symptoms (n=389 cases)*
Malaise (general discomfort)
7 (2)
n (%)§
7 (2)
Night sweats
Human Signs and Symptoms (n=389 cases)*
Night sweats
5 (1)
n (%)§
5 (1)
Faintness (lightheadedness)
Human Signs and Symptoms (n=389 cases)*
Faintness (lightheadedness)
3 (1)
n (%)§
3 (1)
Pallor
Human Signs and Symptoms (n=389 cases)*
Pallor
2 (1)
n (%)§
2 (1)
Hot flash(es)
Human Signs and Symptoms (n=389 cases)*
Hot flash(es)
2 (1)
n (%)§
2 (1)
Flushing (face or body)
Human Signs and Symptoms (n=389 cases)*
Flushing (face or body)
1(<1)
n (%)§
1(<1)
Sweating
Human Signs and Symptoms (n=389 cases)*
Sweating
1(<1)
n (%)§
1(<1)
Flu-like symptoms
Human Signs and Symptoms (n=389 cases)*
Flu-like symptoms
1(<1)
n (%)§
1(<1)
Genitourinary
Human Signs and Symptoms (n=389 cases)*
Genitourinary
6 (2)
n (%)§
6 (2)
Dysuria (pain with urination)
Human Signs and Symptoms (n=389 cases)*
Dysuria (pain with urination)
3 (1)
n (%)§
3 (1)
Dark urine
Human Signs and Symptoms (n=389 cases)*
Dark urine
2 (1)
n (%)§
2 (1)
Hematuria (blood in urine)
Human Signs and Symptoms (n=389 cases)*
Hematuria (blood in urine)
1(<1)
n (%)§
1(<1)
Musculoskeletal
Human Signs and Symptoms (n=389 cases)*
Musculoskeletal
13 (3)
n (%)§
13 (3)
Muscle pain
Human Signs and Symptoms (n=389 cases)*
Muscle pain
10 (3)
n (%)§
10 (3)
Arthralgia (joint pain)
Human Signs and Symptoms (n=389 cases)*
Arthralgia (joint pain)
5 (1)
n (%)§
5 (1)
Muscle fatigue
Human Signs and Symptoms (n=389 cases)*
Muscle fatigue
2 (1)
n (%)§
2 (1)
Backache
Human Signs and Symptoms (n=389 cases)*
Backache
1(<1)
n (%)§
1(<1)
Muscle cramps
Human Signs and Symptoms (n=389 cases)*
Muscle cramps
1(<1)
n (%)§
1(<1)
Neurologic
Human Signs and Symptoms (n=389 cases)*
Neurologic
56 (14)
n (%)§
56 (14)
Dizziness
Human Signs and Symptoms (n=389 cases)*
Dizziness
34 (9)
n (%)§
34 (9)
Paresthesia (tingling sensation)
Human Signs and Symptoms (n=389 cases)*
Paresthesia (tingling sensation)
17 (4)
n (%)§
17 (4)
Weakness
Human Signs and Symptoms (n=389 cases)*
Weakness
15 (4)
n (%)§
15 (4)
Ataxia (loss of coordination)
Human Signs and Symptoms (n=389 cases)*
Ataxia (loss of coordination)
5 (1)
n (%)§
5 (1)
Temperature reversal (hot-cold reversal)
Human Signs and Symptoms (n=389 cases)*
Temperature reversal (hot-cold reversal)
5 (1)
n (%)§
5 (1)
Confusion
Human Signs and Symptoms (n=389 cases)*
Confusion
3 (1)
n (%)§
3 (1)
Neurological symptoms (nonspecific)
Human Signs and Symptoms (n=389 cases)*
Neurological symptoms (nonspecific)
2 (1)
n (%)§
2 (1)
Seizures
Human Signs and Symptoms (n=389 cases)*
Seizures
1(<1)
n (%)§
1(<1)
Ascending paralysis
Human Signs and Symptoms (n=389 cases)*
Ascending paralysis
1(<1)
n (%)§
1(<1)
Ophthalmologic
Human Signs and Symptoms (n=389 cases)*
Ophthalmologic
30 (8)
n (%)§
30 (8)
Eye irritation
Human Signs and Symptoms (n=389 cases)*
Eye irritation
14 (4)
n (%)§
14 (4)
Blurred vision
Human Signs and Symptoms (n=389 cases)*
Blurred vision
5 (1)
n (%)§
5 (1)
Eye burning
Human Signs and Symptoms (n=389 cases)*
Eye burning
4 (1)
n (%)§
4 (1)
Conjunctivitis (pinkeye)
Human Signs and Symptoms (n=389 cases)*
Conjunctivitis (pinkeye)
4 (1)
n (%)§
4 (1)
Periorbital edema (swelling)
Human Signs and Symptoms (n=389 cases)*
Periorbital edema (swelling)
3 (1)
n (%)§
3 (1)
Eye pain
Human Signs and Symptoms (n=389 cases)*
Eye pain
3 (1)
n (%)§
3 (1)
Eye redness
Human Signs and Symptoms (n=389 cases)*
Eye redness
2 (1)
n (%)§
2 (1)
Watery eyes
Human Signs and Symptoms (n=389 cases)*
Watery eyes
1(<1)
n (%)§
1(<1)
Eye symptoms (nonspecific)
Human Signs and Symptoms (n=389 cases)*
Eye symptoms (nonspecific)
1(<1)
n (%)§
1(<1)
Other
Human Signs and Symptoms (n=389 cases)*
Other
30 (8)
n (%)§
30 (8)
Other
Human Signs and Symptoms (n=389 cases)*
Other
28 (7)
n (%)§
28 (7)
Dry mouth
Human Signs and Symptoms (n=389 cases)*
Dry mouth
1(<1)
n (%)§
1(<1)
Anaphylaxis
Human Signs and Symptoms (n=389 cases)*
Anaphylaxis
1(<1)
n (%)§
1(<1)
Unknown
Human Signs and Symptoms (n=389 cases)*
Unknown
9 (2)
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).
Download the data: Human HAB-associated illnesses signs and symptoms [XLS – 20 KB]
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*
Animal Signs*
Animal Signs*
n (%)§
n (%)§
n (%)§
Cardiopulmonary
Animal Signs*
Cardiopulmonary
7 (8)
n (%)§
7 (8)
Shock
Animal Signs*
Shock
1 (1)
n (%)§
1 (1)
Hypotension
Animal Signs*
Hypotension
1 (1)
n (%)§
1 (1)
Labored breathing
Animal Signs*
Labored breathing
1 (1)
n (%)§
1 (1)
Wheezing
Animal Signs*
Wheezing
1 (1)
n (%)§
1 (1)
Cyanosis/pale mucous membrane
Animal Signs*
Cyanosis/pale mucous membrane
1 (1)
n (%)§
1 (1)
Respiratory arrest
Animal Signs*
Respiratory arrest
1 (1)
n (%)§
1 (1)
Dermatologic
Animal Signs*
Dermatologic
2 (2)
n (%)§
2 (2)
Itching
Animal Signs*
Itching
2 (2)
n (%)§
2 (2)
Ear/Nose/Throat
Animal Signs*
Ear/Nose/Throat
1 (1)
n (%)§
1 (1)
Ear irritation
Animal Signs*
Ear irritation
1 (1)
n (%)§
1 (1)
Gastrointestinal
Animal Signs*
Gastrointestinal
50 (54)
n (%)§
50 (54)
Diarrhea
Animal Signs*
Diarrhea
26 (28)
n (%)§
26 (28)
Vomiting
Animal Signs*
Vomiting
24 (26)
n (%)§
24 (26)
Liver failure
Animal Signs*
Liver failure
2 (2)
n (%)§
2 (2)
Painful abdomen (on palpitation)
Animal Signs*
Painful abdomen (on palpitation)
1 (1)
n (%)§
1 (1)
Jaundice
Animal Signs*
Jaundice
1 (1)
n (%)§
1 (1)
Tucked abdomen (arched back)
Animal Signs*
Tucked abdomen (arched back)
1 (1)
n (%)§
1 (1)
Generalized
Animal Signs*
Generalized
59 (64)
n (%)§
59 (64)
Lethargy
Animal Signs*
Lethargy
15 (16)
n (%)§
15 (16)
Anorexia (loss of appetite)
Animal Signs*
Anorexia (loss of appetite)
10 (11)
n (%)§
10 (11)
Weakness
Animal Signs*
Weakness
6 (7)
n (%)§
6 (7)
Collapse (unable to stand)
Animal Signs*
Collapse (unable to stand)
4 (4)
n (%)§
4 (4)
Dehydration (refusing water)
Animal Signs*
Dehydration (refusing water)
2 (2)
n (%)§
2 (2)
Stumbling
Animal Signs*
Stumbling
1 (1)
n (%)§
1 (1)
Whining or abnormal vocalization
Animal Signs*
Whining or abnormal vocalization
1 (1)
n (%)§
1 (1)
Hematologic
Animal Signs*
Hematologic
1 (1)
n (%)§
1 (1)
Unexplained bleeding
Animal Signs*
Unexplained bleeding
1 (1)
n (%)§
1 (1)
Neurologic
Animal Signs*
Neurologic
13 (14)
n (%)§
13 (14)
Seizure/Convulsions
Animal Signs*
Seizure/Convulsions
6 (7)
n (%)§
6 (7)
Ataxia (stumbling, loss of balance)
Animal Signs*
Ataxia (stumbling, loss of balance)
3 (3)
n (%)§
3 (3)
Behavior change
Animal Signs*
Behavior change
2 (2)
n (%)§
2 (2)
Paralysis
Animal Signs*
Paralysis
2 (2)
n (%)§
2 (2)
Opisthotonos (severe hyperextension)
Animal Signs*
Opisthotonos (severe hyperextension)
1 (1)
n (%)§
1 (1)
Stupor (decreased consciousness, unresponsiveness)
Animal Signs*
Stupor (decreased consciousness, unresponsiveness)
1 (1)
n (%)§
1 (1)
Other
Animal Signs*
Other
3 (3)
n (%)§
3 (3)
Other
Animal Signs*
Other
3 (3)
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 [XLS – 19 KB]