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Information for Physicians

Screen for Green

Many Ohioans spend their weekends recreating in and around our state’s lakes, rivers and streams.  Few are aware of the potential for Harmful Algal Blooms (HABs) which could make them sick.

“Screen for Green” is a new Ohio Department of Health program to help busy providers like you identify potential patients with HABs exposure.

HABs are groups of cyanobacteria which can produce illness causing toxins. Symptoms can include gastrointestinal (nausea), neurologic (dizziness) and skin rashes. Severe disease can result in neuro, nephro- and hepatotoxicity depending on the toxin.

For patients presenting with ill-defined gastrointestinal, neuro or skin symptoms AND a recent history of recreating in a waterway, consider HABs toxin exposure. Refer to the “Screen for Green” algorithm and factsheet link below.  

The early identification and reporting of HABs illnesses to public health is critical to reducing additional HABs illnesses in affected recreational waters.  To report a HABs illness, contact the Local Health District Epidemiologist or the Ohio Department of Health.  

Treatment of HABs illness largely involves providing supportive care.

Below are some facts about HABs

  • HABs may occur in recreational waters throughout Ohio.

  • Cyanobacteria in HABs are typically green or red colored and can sometimes be seen on the water surface.

  • Cyanobacteria can migrate in the water column so any water depth can contain toxins.

  • Even if you don’t see a bloom or surface scum doesn’t mean that toxins aren’t present.

  • Even a small amount of swallowed HABs-contaminated water can cause symptoms.

  • Symptoms typically occur within 48 hours.

ODH operates a beach monitoring program that includes BeachGuard, a website listing public beaches and other recreational waters where known toxin advisories are posted around Ohio. Click here to access BeachGuard.

The Ohio Department of Natural Resources and Ohio Environmental Protection Agency monitor state-run beaches and boat ramps for HABs. Private waterways are not routinely monitored, although some voluntarily participate in BeachGuard.  More information on HABs monitoring can be found at the State of Ohio Algae webpage. Click here for Ohio EPA's Algae Information webpage.

Physician Resources

The links below provide helpful resources for physicians.