Parasites

A fatal tropical disease has infected large numbers of foxhounds in the United States. Public health officials fear that humans may contract the disease if the dogs come into contact with sandflies, which transmit the parasite that causes leishmaniasis. Late last year, the Millbrook Hunt Club in New York State realized that many of its foxhounds were sick and dying. The dogs were losing their hair, they had skin lesions, swollen limbs and were wasting away. When vets analyzed fluid from the joints of one dog they found the leishmaniasis parasite.

ILLNESS, far more than bad government or crime, is what holds Africa back from development. AIDS and the revival of malaria come foremost in shortening life spans, destroying work forces, discouraging investment, fostering despair. Sun reporter Douglas Birch gave a riveting account Sunday of the suffering endured by Africans with malaria. He detailed the heroic effort to find a vaccine by physicians at the Walter Reed Army Institute of Research led by Dr. W. Ripley Ballou. Parasitic diseases in Africa -- sleeping sickness and river blindness, along with malaria, tuberculosis and AIDS -- have not attracted as many resources as they might.

Marine scientists have identified a new parasite in the Chesapeake Bay that may be a major factor in the sharp decline of the state's soft-shell clam population. The microscopic creature, which scientists dubbed Perkinsus Chesapeaki on Tuesday, is closely related to Perkinsus marinus, or Dermo, a pest that has devastated Chesapeake Bay oysters for the past 20 years. Dermo and Perkinsus Chesapeaki were found in clams taken from 10 sites in the upper bay between 1990 and 1998. Scientists studying the new parasite say they aren't sure whether it can kill soft-shell clams, the variety that Maryland clam dredgers rely on for their catch.

OXFORD -- A parasite that has been killing crabs from the Gulf of Mexico to Long Island Sound for more than a decade is a suspect in the decline of the commercial crab catch in Maryland's coastal bays.The parasite, known as Hematodinium (he-mat-a-DIN-ee-um) sp, threatened Georgia's $4-million-a-year crab industry this year and shut down crabbing on the Atlantic Ocean side of Virginia's eastern shore in 1991-1992. The commercial catch in Maryland's coastal bays was cut in half last year, the most recent year for which figures are available, and apparently declined again this year.

Scientists have detected the presence of the parasite that caused the largest outbreak of water-borne illness in U.S. history in oysters taken from commercially harvested beds in Chesapeake Bay and its tributaries.The oysters containing Cryptosporidium, which can cause vomiting and severe diarrhea, were taken from beds in the Wicomico, Nanticoke, Potomac and Patuxent rivers, Fishing Bay and Tangier Sound in the fall of 1997 and winter and fall of last year, the scientists reported.The scientists from the U.S. Department of Agriculture in Beltsville, the National Oceanographic and Atmospheric Administration laboratory at Oxford on the Eastern Shore, the Johns Hopkins University School of Public Health and the Centers for Disease Control in Atlanta reported their findings in the September/October issue of the CDC's journal, Emerging Infectious Diseases.

As many as 20 Walkersville households have reported symptoms that might be related to sewage-contaminated tap water, although no positive link to a recent sewer-line break has been established, Frederick County health officials said yesterday.Ellen B. Ristorcelli, director of nursing for the county Health Department, said her staff is collecting stool samples to test at a state laboratory for the presence of one of two microscopic parasites -- giardia or cryptosporidium.Contamination concerns stem from the June 18 break that spilled 900,000 gallons of raw sewage into the ground and contaminated the source of drinking water for more than 7,000 people in the Walkersville area.

Inexorably, tiny parasitic insects from Asia called woolly adelgids are punching deeply and destructively into the hemlock forests of the Eastern United States.Traveling about 30 miles a year or even faster lately, they have fanned out from Virginia to invade the hemlocks' heartland in northern New England and march down the Blue Ridge into North Carolina and westward into West Virginia.The adelgids advertise their presence on hemlock needles by depositing strings of little white egg sacs that look like artificial snow on a Christmas tree.

IN THIS country, major medical news usually consists of high-technology advances in treating big killers like cancer or heart disease. In many parts of the world, it takes far less sophistication to have lifesaving results."

Due to an editing error, an article Saturday about the role of oysters in controlling harmful algae such as Pfiesteria microorganisms misstated the view of three scientists. The three had spoken in another context, agreeing that Chesapeake Bay seafood appeared to be safe. They were Dr. Sandra E. Shumway of Southhampton College at Long Island University, Dr. Katherine Richardson of the Danish Institute for Fisheries Research and Dr. Patrick Gentien of the French Institute for Sea Research.

For many years my brother suffered with diarrhea. His doctor recently cured the diarrhea, by treating him for giardia. Since I have also had intermittent problems with diarrhea, I would like to know how giardia is diagnosed and treated.Chances are you don't have giardia and there is some other explanation for your symptoms. But it's worth checking out. Giardia lamblia is a protozoa, a single-celled animal, responsible for one of the most prevalent parasitic diseases in the world. In its life cycle the parasite exists in two forms or stages: cysts and trophozoites.