Lab Matters Fall 2017 | Page 6

environmental health

by Curtis Andrews, microbiogist laboratory manager, Alabama Department of Public Health-Mobile; Leanne Flewelling, PhD, research administrator II, Florida Fish and Wildlife Conservation Commission; Katherine Hubbard, PhD, research scientist, Florida Fish and Wildlife Conservation Commission; Blaine Rhodes, director, Office of Environmental Laboratory Sciences, Washington State Public Health Laboratories; Drew Sheehan, microbiologist, Alabama Department of Public Health-Mobile; and Sarah Wright, senior specialist, Environmental Laboratories

THE FOUR MOST COMMONLY TESTED TYPES OF MARINE TOXINS:

Algae Toxin Produced Potential Illness Location

Alexandrium *, Gymnodinium *, Pyrodinium bahemese saxitoxins

According to the US Centers for Disease Control and Prevention( CDC), all coastal states report some level of harmful algal blooms( HABs) in their marine waters every year. About 16 different marine alga can produce a wide variety of toxins.

These toxins can bioaccumulate in filterfeeding bivalve molluscan shellfish such as mussels, oysters, clams, scallops and geoducks, harm and kill marine animals, and potentially cause severe human illnesses or death. Human exposure to HAB toxins occurs primarily by eating contaminated shellfish, though some may be inhaled via wave aerosolization. Since the toxins are chemicals and not proteins, they do not break down when shellfish is cooked, pasteurized, frozen or canned. The US Food and Drug Administration’ s( FDA’ s) National Shellfish Sanitation Program establishes guidelines to ensure that shellfish are sanitary and safe for human consumption. CDC’ s Division of Laboratory Sciences Emergency Response Branch develops analytical methods to help identify people exposed to PSPs and other algal toxins. CDC has supported exposure investigations within the US through analysis of clinical samples and works with state and local laboratories to expand their capacity to respond.

The economic impact of HABs can be felt through commercial and recreational shellfish harvesting paralytic shellfish poisoning( PSP)

activities( valued at $ 1 billion or more in some states) and tourism. Many coastal states have well-established shellfish monitoring programs to protect public health and safety, ensuring these industries continue to flourish.

Alabama

Gulf of Mexico, Atlantic coast up to DE

Florida west coast, Atlantic northeast coast, Pacific coast

OR, TX, WA, Long Island Sound, Cape Cod( MA)

Pacific coast, Atlantic northeast coast, FL

* not all species within this genus produce the toxins Source: Woods Hole Oceanographic Institute

In 1991, the Alabama Department of Public Health began monitoring HAB biotoxins in shellfish growing areas along the Alabama Gulf Coast and at four to five regulated shellfish growing water sites. Two microbiologists routinely examine water samples microscopically to quantitate Karenia brevis, Pseudo-nitzschia and Dinophysis. These marine algae can bloom in large numbers and create the“ red tides” found in Gulf waters.

Due to the complex nature of the only FDA-approved method( mouse bioassay) to quantify brevetoxin levels, oyster samples are sent to the Florida Fish and Wildlife Conservation Commission’ s Fish and Wildlife Research Institute( FWC-FWRI). A review of Alabama’ s historical data suggests blooms of significant magnitude occur about every ten years and are most active in the fall months. The impact on Alabama Gulf Coast tourism and the shellfish industry is detailed in the 2015 article,“ Red tide invades Alabama waters, shuts down fall oyster harvest.”

WA PHL Analyst David Nguyen prepares blue mussel samples for extraction and analysis of three algal toxins( saxitoxins, domoic acid, okadaic acid) by shucking the shells from the edible portions. Photo: Shelley Lankford

Laboratory recommendations for starting or expanding a marine biotoxin program:

1. Identify the need for monitoring.

2. Collaborate with and determine responsibilities among state and federal partner agencies.

3. Train laboratory analysts to recognize target algal species and / or perform toxin testing.

4. Pick the most conservative and trusted technology available to perform the toxin tests. You can stand a few false positives, but you cannot have ANY false negatives.

5. Develop a multi-disciplinary response plan for each potential biotoxin affecting your state’ s marine areas.

Florida

Florida’ s state biotoxin testing program is a partnership between the Florida Department of Agriculture and Consumer Services( FDACS), the shellfish harvest area management authority, and FWC-FWRI, which provides technical support through statewide HAB monitoring and biotoxin testing. Analytes tested as part of the $ 2.7 million / year program include ASP, NSP, and PSP toxins. The eight-person program also partners with the National Oceanic and Atmospheric Administration and