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 development
HAB Events and Cases

Human Signs and Symptoms
Animals Signs

OHHABS Development

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 Map working groups for 2014-2016 with state partners, and federal partner logos including the EPA, NOAA, ATSDR, USGS, FDA, Great Lakes Restoration, and the National Parks Service.

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.

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HAB Events and Cases

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.

Map of the United States showing the 18 states that reported to OHHABS during 2016 to 2018.

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.

Figure showing reported HAB events (n-421) with associated human (n=73) and animal cases (n=42)

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.

Graph of reported HAB events and cases by month. Animal cases spiked in May, human cases spiked in July, and HAB events spiked in July.

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.

Graph showing reported HAB event and case occurrence by month; HABs occurred May to November, with domestic animal cases spiking in July, wildlife animal cases spiking in May, and livestock animal cases spiking in June.

Download the data: Reported HAB-associated animal case occurrence by month, 2016-2018 [XLS – 15 KB]

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].

Graph of HAB event and case classification; most HAB events were confirmed (n=370), human cases probable (n=341), and animal cases suspected (n=333).

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].

Graph of animal case classification; most wildlife cases were suspected (n=317), and most pet (n=31) and livestock (n=34) cases were probable.

Download the data: Classification of animal cases by type, 2016-2018 [XLS – 16 KB]

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Human Signs and Symptoms

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.