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April 2005 According to a report in ProMED Mail, the red tide outbreak off the coast of Florida is causing problems for more than just Manatees and other marine life (see Darwin, March 2005). Beach lovers visiting the Southwest Florida shores are complaining of wheezing, coughing and other respiratory problems, suggesting that airborne red tide, a neurotoxin, may be more harmful to humans than previously thought. The large algae bloom of Karenia brevis dinoflagellate, the cause of red tide, has stretched from Tampa Bay to Sanibel Island. The organism releases a toxin that paralyzes the respiratory system of marine life, and can become air borne from waves, wind and boat propellers. Breathing the air borne toxin can cause respiratory symptoms in people, too. However, it is believed these are mild, self-limited problems. Red tide occurs just about every year in Florida, but this year’s outbreak has been unusually persistent, officials said. According to the report in ProMED mail, respiratory complaints have been made to hospitals, doctor’s offices and poison control centers, although state tourism officials have downplayed the effects. However, a study done by Lora E. Fleming and colleagues show that patients with asthma showed a small but statistically significant decrease in forced expiratory volume in 1 second (FEV1) and peak expiratory flow after exposure to red tide toxin. This study to showed objective measurements of adverse health effects from exposure to air borne red tide toxin. The study looked at 59 people with physician-diagnosed asthma, who were taking their normal asthma medications. The patients were examined before and after a one-hour visit to a Florida beach on days with and without red tide. The researchers took nose and throat swabs, performed spirometry and the patients filled out a brief symptom questionnaire. Patients reported more symptoms after red tide exposure, the researchers said in their abstract. (www.niehs.nih.gov) Another study from Sarasota Memorial Hospital looked at a three-month period in 2001 and found that emergency room admissions for respiratory problems were 54% higher for people living along or visiting the coast than during the same time period without red tide, according to the ProMED mail report by Beth Daley, which originally appeared in the Boston Globe. The Mote Marine Laboratory recommends that people living near the red tide beaches should keep their windows closed, the air condition or heat on, and check the unit’s filter. Check the marine forecast: offshore winds mean fewer red tide toxins; people with chronic lung disease should be vigilant about using their medications; and seek medical attention if symptoms worsen. Alongshore samples recently collected from the bloom area contained very low to medium concentrations of K. brevis, according to the Florida Fish and Wildlife Research Institute. No positive counts were found south of Sarasota Bay. Dead fish were reported at the end of March early offshore of Fort Myers. Dead fish and birds (two pelicans) were also reported in lower Tampa Bay. Forty-one dead manatees have been found since March 4. In addition, the Fish and Wildlife Research Institute released figures about manatee deaths from 2004. There were 276 deaths, a drop from the 370 recorded for 2003. Of the 2003 deaths, 96 may have succumbed to red tide exposure. In 2004, only four manatees are suspected to have died from red tide. – Marie Rosenthal PreMED-mail, the Program for monitoring Emerging Diseases, is a program of the International Society for Infectious Diseases. For information and free subscription, go to www.promedmail.org. |
