TAMPA, Fla., March 29 (UPI) -- A biology professor at the University of South Florida has determined that many of the manatees that died in the past year were infected by a water-pollution-related parasite.
My Lien Dao examined 10 dead manatees, an endangered species, and found microsporidia in their lungs, livers, kidneys spleens and lymph nodes.
She said Friday the organism was not the sole cause of death but was part of the problem.
"We can say it is a contributing factor in all 10 deaths but we cannot say they died just from the microsporidia," she said.
Identification of a kind of microsporidia known to infect humans and other non-marine mammals suggested the possibility of water pollution from sewer runoff, she said.
State and federal wildlife officials say 325 manatees were found dead last year and many of them had wounds inflicted by watercraft propellers. Last year was the second most deadly year for manatees.
Officials said 81of the animals' deaths were caused by boaters, 30 by last year's cold winter weather, and the cause was listed as undetermined in 108 cases.
"Open wounds inflicted by watercraft propellers may add to the problem as they open the door to massive infection and rapid spreading of the microorganism to various organs and tissues," Dao said.
She said she found the single-cell organism in all 10 carcasses she examined.
"When you have 10 out of 10, that's a scary thing. This is a big ecological problem," she said.
"This was the first time that the same infections disease was found in all the animals tested."
She is worried about the fate of the manatees because the organism is released in the urine and feces of infected individuals, and is likely to spread to the entire manatee community swimming and ingesting microsporidia in contaminated water.
The single-cell parasites can cause diarrhea in healthy humans. But with people with weak immune systems -- AIDS victims, young children and the elderly -- it can invade other organs. That can lead to a variety of problems including pneumonia.
"It's really like a silent killer," Dao said.
She said the organism was also found in the bodies of a baby dolphin and a baby sperm whale found dead in Florida waters.
