The New Straits Times, Feburary 14, 1997
Q: One day I noticed may daughted licking a used mosquito vapour mat but she did not develop any unusual symptoms. Should I bring her to the doctor for further observation if this incident occurs again?
A: The usual class of active ingredient found in mosquito vapour mats (or also known as vape mats) is pyrethroids which are synthetic chemicals of a natural class of compounds known as pyrethrins. Pyrethrins have been used as an insecticide for over 100 years. These compounds are naturally occurring substances consisting of esters of pyrethric and chrysanthemumic acids. They are the active chemicals of pyrethrum which is the extract of the chrysanthemum flower, chrysanthemum cineriaefolium. Due to the heavy demand for the natural compound of pyrethroids were introduced in the 1950s so as to minimise dependence on the natural pyrethrins. Examples of synthetic pyrethroids include permethrin, allethrin and cypermethrin.
As compared to other pesticides, pyrethrins and pyrethroids have got a lower toxic level and considered to be among the safest insecticides. In the above case, since the presence of pyretherins was most likely to be negligible, no unusual manifestation is likely to occur. Adverse effects are usually limited to mild allergic manifestation due to inhalational or dermal exposure in sensitive individuals, in particular patients with allergy to pollen such as ragweed.
Allergic syndromes associated with pyrethrins include inflammation of the skin (dermatitis) allergic rhinitis, asthma, hypersentivity, pneumonitis and non-fatal anaphylactoid reactions.
In some mosquito vapour mats, piperonyl butoxide would normally be included together to obtain a synergistic effect with pyrethrins. This compound is considered minimally toxic and not reported to be an allergen.
Based on the above explanation, the National Poison Centre is of the opinion that certain individuals having allergic problems should be brought to medical attention immediately if ingestion of such mosquito vapour mats occurs.
