For more information, contact Dr. Suzanne Jenkins, 804-786-6261
Virginia Department of Health Urges Swimmers to Avoid Red Tides and Fish Kills
(Richmond, Va.) -- The Virginia Department of Health is warning people to avoid swimming in or contact with bodies of water in which red tides or dead fish are present. This precaution follows a fish kill in a Maryland tributary of the Chesapeake Bay involving more than 10,000 fish. The section of the Pokomoke River affected by the kill is bordered by Somerset County, Md., to the west and Accomack County, Va., to the east. The kill was reported near the Maryland shore around 10 a.m. on August 6.
The cause of this fish kill is unknown, and water and fish samples are being analyzed. A water sample in May showed possible evidence of a Pfiesteria-like organism, but Pfiesteria has not been found in any other samples. The Pokomoke has been monitored for the past several months for the presence of the newly discovered dinoflagellate Pfiesteria, which has a complicated life cycle of at least 15 life stages. In a few stages it can produce a poison that attacks fish. It has been associated with "fish kills" in the Neuse River in North Carolina.
A dinoflagellate is a microscopic organism that sometimes behaves like a plant and sometimes like an animal. In general, when dinoflagellates reproduce to huge numbers they can cause a discoloration of the water, often referred to as a "red tide." However, Pfiesteria is not associated with a significant dis- coloration of the water. Most red tides do not directly harm humans or fish, however, when the organisms die, oxygen in the water is reduced which can result in fish dying. Red tides occur commonly in Virginia waters, but the kind that are dangerous to humans have never been identified here.
"If you can see discoloration in the water, it's not Pfiesteria, but there's the potential for harm and it's prudent not to have any contact with the water," said Dr. Suzanne Jenkins, assistant state epidemiologist. "If there's something that's causing massive fish kills, you probably don't want to have any contact with that water either."
There has been no conclusive evidence of human illness associated with exposure to Pfiesteria. In other states, some people working with this organism in the laboratory and some commercial fishermen have reported headaches, memory loss, nausea, respiratory illness, and skin rashes after contact with Pfiesteria-infested water, but the relationship between Pfiesteria and human illness is unclear.
"So far, we've had no confirmed cases of Virginians becoming ill from exposure to Pocomoke River water," said State Health Commissioner Randolph L. Gordon, M.D., M.P.H. "However, our Accomack County Health Department has asked its local physicians to inform us of any patients whose illnesses might be linked to the river."
The Virginia Department of Health recommends the following:
The Virginia Department of Health and the Accomack County Health Department are working closely with the Maryland Department of Health to identify the cause of this fish kill.