- A massive red tide off the beaches of southwest Florida
is causing an outbreak of wheezing and coughing among beachgoers, and new
evidence suggests that the effects of an airborne neurotoxin the tide produces
may be more harmful than health officials previously thought.
- Since early January 2005, a large algae bloom stretching
from the mouth of Tampa Bay to Sanibel Island has been releasing into the
air odorless toxins that waft onto beaches with every onshore wind. Red
tide occurs nearly every year, but this year's bloom is unusually persistent,
parking itself in coastal waters and failing to dissipate.
- Calls about the toxins have poured into hospitals, doctors'
offices, and poison control centers, and some doctors say the current algae
bloom is producing more reports of health difficulties than any other red
tide they can remember.
- ''It's awful -- you choke," said a visitor from
Massachusetts who was visiting Lido Beach in Sarasota last week with her
husband. ''As soon as we got here we started to cough."
- Florida tourism officials have long downplayed the human
respiratory effects of red tide, in part because exposure depends on shifting
winds and the toxins affect some people differently than others. But some
results from a 5-year, $6.5-million federally funded series of studies
by scientists and health officials being published next month show for
the 1st time that the events may be causing significant health problems.
- During a 3-month 2001 red tide event examined in the
study, Sarasota Memorial Hospital's emergency room admissions for respiratory
problems were 54 percent higher for people living along or visiting the
coast than during the same time period the next year, when there was no
red tide. There was no similar spike inland.
- The study also documents that beachgoers with chronic
respiratory problems have reduced lung capacity after even a short exposure
to red tide, although it's unclear how long the problems last.
- ''For years we've had anecdotal information this is happening,
but you can't decide public policy on anecdotes," said Barbara Kirkpatrick,
staff scientist at Mote Marine Laboratory in Sarasota and one of the lead
researchers of the study, which will be published in a series of 7 papers
in Environmental Health Perspectives. She wants state and local officials
to develop a visible warning system to alert beach visitors to red tides.
- Still, healthy people appear to be affected only temporarily;
their watery eyes and scratchy throats can be cured by simply going inside
an air-conditioned room or leaving the beach.
- Florida's version of red tide -- actually more green-brown
in appearance than red -- is a different organism from the one blamed for
the red tide that appears off the New England coast, which doesn't produce
an airborne toxin and is most dangerous to humans if they eat contaminated
- First documented in the 1800s, Florida's red tide is
caused by a naturally occurring single-celled organism, _Karenia brevis_,
and can stretch tens of miles wide and long. The current bloom is patchy,
but stretches about 50 miles north to south and about 20 miles from shore
in some places, according to researchers at Mote. For reasons that are
not entirely understood, the organism multiplies and accumulates in the
Gulf of Mexico almost every year, reaching concentrations that discolor
the water with the tiny plants' pigments. The neurotoxin is released when
the fragile cells die -- and also perhaps when they are smashed in the
surf. Red tide does not normally occur on Florida's East Coast.
- This year's outbreak has killed thousands of fish, many
of which could be seen last week speckling the shoreline along the Siesta
Key and Lido beaches. At least 44 endangered manatees are believed to have
died from exposure to the algae, according to wildlife officials. People
who eat seafood contaminated by the neurotoxin can become ill. Still, swimming
is allowed and most people report few adverse reactions.
- Whether the blooms have been getting worse or are persisting
longer are matters of debate among environmental researchers in this state,
where tourism is a major industry. Some studies have suggested sewage and
other runoff might be to blame. Florida wildlife officials say no evidence
exists to show that the blooms are increasing in frequency or lasting longer.
''We haven't seen an increase in the duration or frequency of red tides,"
said Cynthia Heil, a scientist with the Florida Fish and Wildlife Research
- State officials also say it's unclear whether this year's
bloom has caused more medical problems.
- Symptoms associated with exposure to red tide's neurotoxins
can mimic the start of a cold, change with variable winds, and affect different
people in different ways. Several doctors who deal with red tide complaints
say that they always see an uptick in emergency room visits and calls during
red tide, but that sometimes it can be hard to sort out which complaints
are truly related to red tide and which are separate respiratory events.
- ''Still, I've heard about more difficulties this year
than any year in recent memory," said Dr. Terrence Kane, a pulmonologist
with Lung Associates of Sarasota who was one of the authors of the emergency
room admission study. ''There have been bad spells before, but they have
been relatively short-lived."
- How best to warn the public about red tide's respiratory
effects is a delicate subject in southwest Florida, where so many people's
livelihoods rely on tourism. Although Florida public health officials have
stepped up awareness campaigns in recent years with pamphlets and public
service messages that warn people with respiratory problems to stay away
from beaches during a red tide bloom, several first-time tourists to the
area said they were unaware why they were coughing during a particularly
gusty Wednesday night last week on Lido Beach.
- Because Florida does not close beaches during red tide
events, lifeguards often educate beach-goers. State public health officials
say they and Kirkpatrick are developing a pilot program to place beach
signs warning about the dangers.
- ''We do tell people to bring an inhaler if they are asthmatic,"
said Tamara Pigott, beach and shoreline project manager for Lee County
Visitor and Convention Bureau in Fort Myers. ''For most people, it's a
nuisance. It's not going to ruin their vacation."
- Kirkpatrick, along with Daniel Baden of the University
of North Carolina-Wilmington, lead investigator on the forthcoming study,
said there are still many unknowns about red tide, such as how long symptoms
can last and the potential for exposure to cause chronic and immune system
- ''You feel the effects before we have the ability to
measure them. It's happening at very low levels," said Baden. His
groups' research, funded largely by the National Institute of Environmental
Health Sciences with help from the Centers for Disease Control, is under
review for another 5 years of funding. ''We still need to learn more."
- Red tide is caused by several toxic algae. Depending
upon the toxin, it
- is also known as paralytic shellfish poisoning (PSP),
because it causes
- shellfish to be toxic for consumption. Generally the
effects in people are
- short-lived and not serious. - Mod.TG
- Patricia A. Doyle, PhD
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