Warming ocean temperatures will bring a slew of environmental
changes, and one negative consequence may be an increase in
ciguatera fish poisoning in people who dine on reef fish.
To counter an expected rise in cases in the Caribbean, the Emerging
Pathogens Institute (EPI) at the University of Florida is teaming
up with partners in the U.S. Virgin Islands to launch a Ciguatera
Fish Poisoning Monitoring project. Partners include the University
of the Virgin Islands, the University of Maryland School of
Medicine, Woods Hole Oceanographic Institution, Schneider Regional
Medical Center on St. Thomas, the Food and Drug Administration
Dauphin Island Lab and Florida State University.
Ciguatera poisoning is caused by a chemical assemblage of
naturally-occurring toxins, called ciguatoxins, which are produced
by microscopic photosynthetic organisms that live on seaweed and
other surfaces within reef communities. When herbivorous fish eat
seaweed or algae, they consume the organisms too, and the
ciguatoxins accrue in the fish's flesh.
The toxins build up over time in predatory reef fish that feed
higher up the food chain. People who rely on reef fish as a staple
protein in their diet are at risk for contracting ciguatera
poisoning. It is thought that climate change and warming oceans
will trigger an increase in harmful algal blooms, with an
associated uptick in cases of ciguatera fish poisonings in people
who eat fish that feed at affected reefs.
A news conference announcing the start of the Ciguatera Fish
Poisoning Monitoring project, and providing more details, will be
held in Chase Auditorium (Business building room 110) on the St.
Thomas campus of the University of the Virgin Islands on Friday,
Dec. 4 at 11 a.m. EPI director Dr. Glenn Morris, will give a short
presentation on the project, and there will be time for questions.
Dr. Don Anderson of the Woods Hole Oceanographic Institution will
also speak about the Gambierdiscus cells that are the source of the
ciguatera toxin. Dr. Clayton Wheatley, the chief Emergency Medicine
physician at the Schneider Regional Medical Center, will discuss
poisoning symptoms.
The study includes reef surveys to better understand why and where
Gambierdiscus occurs, and what causes its persistence or
overabundance in certain marine communities. For example, warmer
ocean temperatures may provide environmental conditions conducive
to its growth. But human-caused reef disturbances such as dredging,
freshwater runoff, sewage pollution and ship groundings may also
play a role in increasing the abundance or distribution of
Gambierdiscus. Environmental factors can also alter the patterns of
ciguatera fish poisoning, such as pollution and reef damage from
storms or coral beaching. Monthly surveys will target two sites
south of St. Thomas, an area known to shelter fish that produce
ciguatera fish poisoning and fish will be tested for detection of
internal toxins.
On land, project staff will work with emergency room doctors at the
Schneider Regional Medical Center to track cases of ciguatera
poisoning in people admitted for treatment. Staff will also survey
local residents and tourists for incidences of ciguatera poisoning
to capture cases where people may not have sought medical
treatment. The goal of these efforts is to establish the "normal"
background levels of ciguatera poisoning, so as to discern if the
rates are increasing and what environmental factors are
correlated.
Reef fish known to be potential carriers of ciguatoxins include:
barracuda, black grouper, blackfin snapper, cubera snapper, dog
snapper, greater amberjack, hogfish, horse-eye jack, king mackerel,
and yellowfin grouper, according to the CDC.
Classic symptoms of ciguatera poisoning appear within hours to a
few days after eating infected fish, and they include
electric-shock-like or painful sensation upon exposure to hot and
cold, as well as nausea or vomiting. Neurologic symptoms such as
intense itching and tingling fingers or toes are also typical.
Treatments are available, and the symptoms may pass within a few
days to six months.
Ciguatera poisoning is an under-reported public health problem.
Some scientists estimate that there are 50,000 to 500,000
poisonings globally each year. In the Virgin Islands and Puerto
Rico, it's thought that as many 20,000 to 40,000 illnesses occur
annually. The annual incidence rate may approach 10 percent of
local island populations. Unfortunately, ciguatera fish poisoning
may disproportionately affect certain demographic groups, with
subsistence fishermen more susceptible.
Lessons from French Polynesia show a strong correlation between
warming ocean waters and an uptick in ciguatera fish poisoning in
people. However, data are scarce for the Caribbean. And because the
effects of global climate change will vary regionally, the EPI and
its partners believe that it is important to get ahead of this
problem and better understand the regional ocean ecosystem in the
Caribbean in order to predict and understand how ciguatera fish
poisonings may change in the future.
Ciguatera poisoning is a major public health problem in the Virgin
Islands, Puerto Rico and the Florida Keys. It is also problematic
in Hawaii and island protectorates in the South Pacific.
The EPI and its partners desire a high level of communication about
this project with local stakeholders, including: residents,
fishermen, medical professionals and government officials. All
those who experience symptoms that may be ciguatera-related are
urged to contact their medical professionals so the team can
register the incident and obtain data about the source of the fish,
its toxicity and the nature of the illness. The public,
stakeholders and local media are encouraged to attend the news
conference.
SOURCE LIST:
For news conference logistics:
University of the Virgin Islands: Patrice Johnson (Director of
Public Relations, Univ. of Virgin Islands): pjohnso@uvi.edu, (340) 693-1058.
MEDIA, PLEASE RSVP TO PATRICE IF YOU PLAN TO ATTEND.
For research/project questions:
UF/Emerging Pathogens Institute: Dr. Morris (Principal
Investigator) jgmorris@epi.ufl.edu,
(352) 273-7526
For medical questions:
Schneider Regional Medical Center: Sam Topp, (340) 776-8311 ext.
2315