Ants Can Cause Asthma, Allergies

Pharaoh Ants Blamed in 2 Asthma Cases

Medically Reviewed by Michael W. Smith, MD on February 05, 2005
From the WebMD Archives

Pharaoh Ants Blamed in 2 Asthma Cases

Feb. 25, 2005 -- Household ants can cause allergies and asthma.

Researchers say if you see ants in the house, then they should be taken into consideration if anyone has breathing problems.

Many insects (including cockroaches) have been reported to contribute to respiratory problems. Now, the pharaoh ant joins the ranks of suspect insects.

The tiny, yellow pharaoh ant came from the tropics but can now be found just about everywhere, having been carried throughout the inhabited world, say the researchers. The ants live indoors for warmth.

"Pharaoh ants nest in secluded spots and favor temperatures between 80-86 degrees Fahrenheit," according to the University of Nebraska web site.

"These ants are frequent house invaders, often found around kitchen and bathroom faucets where they obtain water."

Invasion of the Ants

Researchers Cheol-Woo Kim, MD, PhD, and colleagues found that pharaoh ants were responsible for asthma in two middle-aged women.

One 46-year-old woman had sneezed, coughed, and wheezed for a year. The other patient was 58 years old. Her coughing, wheezing, and chest discomfort had lasted a long time. For five years, she'd known she had asthma, with symptoms worsening every now and then.

Both women said they didn't smoke, own pets, or have mold problems at home. But they both said ants were present in their homes. Call it patients' intuition -- the women thought the ants were to blame for their breathing problems, even though they didn't think they'd been bitten or stung by an ant.

The doctors visited the women's homes to gather ants for analysis. In a lab, the researchers pulverized the ants, making ant extracts to test for allergic reactions.

Both women showed allergic reactions to the ant extract. But 10 healthy people and 10 other asthma patients didn't react to the ant extract.

The results show that pharaoh ants can cause respiratory allergies in sensitive patients, write the researchers. More work is needed to figure out exactly how this process works.

The research appears in February's Annals of Allergy, Asthma & Immunology. Kim works in the internal medicine department at the Inha University College of Medicine in Incheon, South Korea.

Ridding Your Home of Pharaoh Ants

Pharaoh ants may be the most difficult kind of building-invading ant to get rid of, according to Michigan State University's (MSU) web site.

"The best method of controlling pharaoh's ants from an established nest inside the home is to locate the nest and treat it directly with a residual insecticide that is registered for use inside homes," says the site.

"This strategy serves two purposes: It deals with the problem rather than the symptom [and] drastically reduce[s] pesticide use by eliminating unnecessary sprays."

A take-no-prisoners approach is required. "Unless you kill the whole colony, they will move to another location or split and establish several new colonies," says MSU. Because colonies tend to split, the University of Nebraska web site recommends baiting instead of residual insecticides.

Prevention also helps. The MSU web site recommends caulk, weather stripping, and other repairs to seal up gaps around doors, windows, and pipes.

"Check your roof for water damage under shingles and the slashing around chimneys, standpipes, and other roof and bathroom vents."

If you see ants in your workplace, take care if you bring work materials home. "It doesn't take many individuals to start a 'transplanted' colony," says the MSU web site.

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SOURCES: Kim, C., Annals of Allergy, Asthma & Immunology, February 2005; vol 94: pp 301-306. University of Nebraska Cooperative Extension in Lancaster County, "Ant Identification." Michigan State University Department of Entomology, "Pharaoh's Ant."

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