Associate Professor Rob Siebers

As part of the He Kura Asthma Study, funded by the Health Research Council of New Zealand, researchers from the University of Otago, Wellington collected floor dust samples from 136 classrooms in 12 primary schools and analysed it for allergens from cats, cockroaches, horses and cows, dust mites and peanuts. Their study is published in the New Zealand Medical Journal today.

Lead author Associate Professor Rob Siebers says a quarter of all classroom carpets had high enough levels of cat dander, produced in cat saliva and sebaceous glands, to potentially cause respiratory symptoms in cat sensitised children.

“These levels of cat allergen are most likely due to passive transfer from children’s clothing, as there are generally no cats on school premises.”

Of the 136 classrooms, 37 had detectable levels of cow dander allergen, while 82 had detectable levels of horse dander, albeit at very low levels. Three of the classrooms had low and barely detectable levels of cockroach allergens.

Only one of the classrooms had measurable levels of peanut allergen, but these were also at such a low level as to be barely detectable.

Associate Professor Siebers says this was likely a result of most parents following school guidelines on avoiding peanut products in children’s lunches.

“We believe adherence to this advice, plus frequent classroom vacuuming has resulted in the virtual absence of peanut allergen exposure in our study.”

Despite New Zealand having some of the highest levels of house dust mite allergens in the world, the researchers found levels to be relatively low in the classrooms.

“Although we detected house dust mite allergens in nearly all the classrooms studied, none of the levels were at a level associated with respiratory symptoms,” Associate Professor Siebers says.

“We believe that the cleaning practices adopted by the schools, mainly daily vacuum cleaning, were responsible for the much lower levels of allergens in the classrooms, compared to the domestic environment.”

Associate Professor Siebers says with the high prevalence of asthma and allergy in New Zealand, schools should consider replacing carpets with smooth flooring to reduce children’s exposure to cat allergens.

The study was supported by grants from the Health Research Council of New Zealand and from the University of Otago.


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