Pfiesteria piscicida is a dinoflagellate of the order Dinoflagellida. These are an order of minute plantlike, chiefly marine protozoan, organisms that have both plant and animal affinities. They are the suspected cause of a phenomena known as “red tide,” which results in the deaths of various marine life. Some species can secrete a powerful neurotoxin that can cause severe reactions in humans who eat infected shellfish. There are several thousand dinoflagellates that have been identified with about two dozen known to produce toxins.
The following is taken from The New York Times, August 27, 1996: “Like something out of a horror movie, the cell from hell attacks its victims in gruesome ways, frequently changing its body form with lightning speed. The unicellular animal, called Pfiesteria piscicida has at least 24 guises it can assume in the course of its lifetime. It can also masquerade as a plant or lie dormant for years in the absence of suitable prey. Armed with a voracious appetite and vast reproductive powers, the microscopic animal moves through coastal waters to kill fish and shellfish by the millions and to poison anglers and others, producing pain, narcosis, disorientation, nausea, fatigue, vomiting, memory loss, immune failure, and personality changes. Its toxins are so deadly that people who merely inhale its vapors can be badly hurt.”
This toxic microbe has caused massive fish kills, especially along the East coast of the US. More than a billion fish have died in North Carolina waters alone. For many years in North Carolina, pfeisteria was known as Gymnodinium aurantium. Apparently, it was a name coined by a lazy biologist who did not want to go through the tedious formality of naming the organism properly. Even though pfeisteria is not a new microorganism, it seems to have turned into a pathogen. One reason seems to be the vast increase in the pollution of waterways by animal waste, especially that of hogs. Large amounts of waste dumped into waterways curtail oxygen supplies, causing fish to suffocate while bacteria thrive. Along the Gulf of Mexico, south of Louisiana, there is a “dead zone” of nearly 7,000 square miles as a direct result of animal waste contamination. All over the country, the stories are the same, with “streams in Missouri” being “little more than open sewers,” says a former USDA food safety inspector.
The pfeisteria population explodes when too many such nutrients as nitrogen and phosphorus from animal waste, enter the water, resulting in an increase in plant formation in the water. This causes the pfeisteria population to explode, forming dense, colored “blooms” that exhaust the oxygen supply. If the population explosion is sudden enough, the species undergoes a change of its own, producing toxins. These blooms are called “red tides,” which poison the water supply. Fish, by the millions, are killed, as are the birds that feed on them. Shellfish often manage to survive, but are contaminated enough to cause severe illness in those eating them, including humans. Red tides baffle marine scientists for several reasons. While researchers knew what they were, they did not know what caused them, how to predict them, or how to stop them once they had begun. What has become apparent to many scientists is that they are increasing in frequency around the world.
The first record of a “red tide” is found in the Bible in Exodus “…and all the waters that were in the river were turned to blood. And the fish that were in the river died, and the river stank, and the Egyptians could not drink of the water of the river; and there was blood throughout all the land of Egypt”. When Captain George Vancouver and his crew landed in British Columbia in 1793, the Inuits told him that they did not eat shellfish after the tides glowed at night. It was later determined that the glow was caused by blooms of a phosphorescent dinoflagellate (pfeisteria) that produced a toxin so potent that a pin-size amount could kill a human being.
There are four routes of exposure to pfeisteria:
- eating infected fish or shellfish,
- skin contact of contaminated water,
- through an open sore,
- inhaling vapors.
In humans, symptoms include the following: sores, severe headaches, blurred vision, nausea, vomiting, difficulty breathing, kidney and liver failure, memory loss, and/or severe cognitive impairment. Water splashed on the face can leave a human being immediately disoriented with short term memory loss that can last for months. In fish, the organism eats away at the flesh, leaving gaping holes in their bodies. Their toxins can kill fish outright in a matter of minutes.