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EDITORS AND NEWS DIRECTORS: The University of Iowa will provide daily pollen counts beginning Monday, Aug. 10, and continuing throughout ragweed season. For daily counts, call the UI pollen count information line at (319) 335-7641 or access the UI pollen count website at

UI researcher says it's a bumper crop of ragweed this year

IOWA CITY, Iowa -- Allergy sufferers, take cover. There's a bumper crop of ragweed ready to start pollinating, according to John Weiler, M.D., professor of internal medicine at the University of Iowa College of Medicine and an allergy researcher.

Watery eyes, scratchy throats, runny noses and sneezing mark the beginning of ragweed season, a stretch of late summer dreaded by millions of people with allergies. Weiler said the traditional start of the ragweed season is about Aug. 10.

"I thought it might start a little earlier this year because of the early spring, but we're right on schedule," Weiler said.

Ragweed allergies -- also known as hay fever -- affect nearly 15 percent of Americans. Iowa and other Midwestern states offer ideal conditions for the ubiquitous ragweed plant, which releases its pollen into the air for about six weeks starting in mid-August.

"Every year is a good year for ragweed and a bad year for people with allergies," said Weiler. "The plant always grows well in Iowa, regardless of weather."

The chief culprits are actually two plants, Ambrosia artemisifolia, or common ragweed, and Ambrosia trifida, best known as giant ragweed or horseweed. Each year, more than 250,000 tons of their microscopic pollen grains are blown about the United States.

Starting Monday, Aug. 10, and continuing through the end of ragweed season in late September, the UI College of Medicine will offer daily pollen counts to help people with allergies gauge their symptoms. Those pollen counts will be posted on the World Wide Web at

A thin, transparent tube atop a building on the UI health science campus collects airborne pollen grains that are measured by researchers. Though daily counts record the amount of pollen detected over the previous 24 hours, they are usually a good indicator of current conditions.

A pollen count of 200 or less is said to fall into the "comfort zone," meaning that most people will be free of allergy symptoms. The "discomfort zone" includes counts from 220 to 1,000 and indicates that most people with ragweed allergy will feel its effects. Counts greater than 1,000 -- the "severe discomfort zone" -- mean serious symptoms in people who are most sensitive to ragweed and milder reactions in those who seldom experience symptoms at lower levels.

Allergies occur when the body's immune system overreacts to an otherwise harmless substance like ragweed pollen. Inhaled pollen adheres to antibodies produced by the body and triggers an immune reaction that causes respiratory symptoms, or allergic rhinitis. During ragweed season, some people allergic to the plant may also react to foods that contain similar proteins, including chamomile, cantaloupe, honeydew and watermelon.

Allergy symptoms can be severe, even incapacitating, and avoiding pollen on the worst days is the best way to prevent symptoms. "If possible, stay indoors in air-conditioned areas, particularly in the early morning when the ragweed plant produces most of its pollen," Weiler said. The safest times to venture outside are in late evening or after a rainfall.

Since ragweed pollen clings to hair and clothes, washing one's hair before bedtime may reduce symptoms, as can frequent vacuuming, dusting, and laundering bedding. Contact lenses can increase eye irritation, so people with ragweed allergies may want to avoid them on heavy pollen days.

Non-prescription antihistamines and nasal sprays may also provide relief, but relying on sprays can bring additional problems. When overused, sprays can cause swelling in the nose and mimic allergy symptoms. Physicians can prescribe stronger medications for people with the worst symptoms. For more information, consult your physician or other health care provider.

Weiler and other researchers at the UI are conducting two studies during ragweed season '98. In one, participants are invited to spend Saturday, Aug. 29, at Iowa City's City Park recording their allergy symptoms while testing a new allergy medication.

In the other study, participants will record their allergy symptoms and receive allergy treatments for one week. For more information, call 1-800-356-1659 or 356-1659 locally.