With the frequency of rainfall these days and the fairly high temperatures prevailing across the island, there is bound to be mosquito proliferation, especially if people allow water to remain for more than a week or so on their roof-tops, and in their gardens and immediate surroundings - for example in flower vases and flower pots, tin cans, discarded tyres, drums, pails, etc. This is because mosquitoes need water for their development and it takes them some 8 to 10 days to complete their life-cycle under warm and humid conditions. Since, to repel mosquitoes that come to bite, many people make use of Vape-mat and mosquito coils in their homes, we have thought it appropriate to share some information with your readers regarding these products.
We must mention that there is an interesting article in Le Mauricien of Saturday 2 March 2013 entitled “'Infections Virales. Depuis le 28 janvier - 17788 cas d'infections respiratoires aiguës….” However nothing is said about Vape-mat, mosquito coils, or cigarettes for that matter, as possible contributing factors in some of these cases of “infections respiratoires aiguës”.
We must point out that much of the information given below is from the Internet. The active ingredient in Vape-mat is allethrin, a pyrethroid insecticide. When it is inhaled there may be a feeling of dryness in the throat. The long term use of Vape-mat can cause wheezing and respiratory problems that may lead to asthma, inflammation of the nose, itchiness in the eyes and other side effects.
A mosquito coil, locally known as 'sandale moustique' or 'serpentin', is even worse than Vape-mat since, on top of the noxious products due to the insecticide it contains, the coil emits smoke also as it slowly burns.
This coil, usually shaped into a spiral, is mosquito-repelling incense and is typically made from a dried paste of pyrethrum powder. The coil is usually held at the center, suspended in the air to allow continuous smoldering and this produces a mosquito-repellent smoke. Burning begins at the outer end of the spiral and progresses slowly toward the centre.
The mosquito coil was developed around 1890 by a Japanese businessman, Eiichiro Ueyama. At that time in Japan, people usually mixed pyrethrum powder with sawdust and burned it in a brazier or incense burner to repel mosquitoes. Initially, Ueyama created incense sticks mixed from starch powder, dried mandarin orange skin powder, and pyrethrum powder.
The active ingredients found in mosquito coils can be some of the following :
Pyrethrum - a natural, powdered material from a kind of chrysanthemum plant.
Pyrethrins - an extract of insecticidal chemicals in pyrethrum.
Allethrin - the first synthetic pyrethroid.
Dibutyl hydroxyl toluene (a derivative of benzene) and Piperonyl butoxide - optional additives which improve the effectiveness of the pyrethroid insecticide.
Advantages : Modern-day mosquito coils burn without flame for up to eight hours of continuous repelling action. In quantitative tests, they provide about 80% protection. Mosquito coils are also inexpensive and easy to use.
Disadvantages : There are several hazards that are known to be caused by mosquito coils. In 1999, sparks from mosquito coils ignited a fire that swept through a three-story dormitory building at a summer camp in South Korea ; 23 persons, including 19 children, died in the blaze. Recent studies have shown that the smoke generated from burning mosquito coil carries certain health concerns - one burning mosquito coil produces the same amount of particulate mass as 75-137 burning cigarettes ; and the emission of formaldehyde from one coil can be as high as that released by 51 burning cigarettes. Some of the products are believed to be carcinogenic.
Pyrethrum is the name of a natural insecticide made from the dried flower heads of Chrysanthemum cinerariifolium, a perennial plant that looks like the common daisy. The plant is called the Dalmatian chrysanthemum to denote its origin in Dalmatia, a region of the Balkans. The flowers, typically white with a yellow center, are pulverized and the active components, called pyrethrins, contained in the seed cases, are extracted and sold in the form of an oleoresin. This is applied as a suspension in water or oil, or as a powder. Pyrethrins attack the nervous systems of all insects. When present in amounts less than those fatal to insects, they still appear to have an insect repellent effect. They are harmful to fish, but are far less toxic to mammals and birds than many synthetic insecticides. They are not persistent, being biodegradable, and they also decompose easily on exposure to light. Pyrethrum was used for centuries as an insecticide in Persia and Europe. In 1998 Kenya produced 90% (over 6,000 tonnes) of the world's pyrethrum. Presently, pyrethrum is commercially grown in countries such as South Africa, Japan, Tanzania Ecuador and Tasmania.
Research has found that Neem oil is effective as a mosquito repellent for up to 12 hours. Citronella oil's mosquito repellency has also been verified, including effectiveness in repelling certain Aedes mosquitoes but requires reapplication after 30 to 60 minutes.
There are several widespread, unproven theories about mosquito control, such as the assertion that garlic or ultrasonic devices can be used to repel or control mosquitoes.
The electronic devices based on sound production, particularly ultrasound (inaudibly high frequency sounds) have been shown to have no effect as mosquito repellents by studies done by many universities. Moreover, some manufacturers of “mosquito repelling” ultrasonic devices have been found to be fraudulent, and their devices were deemed “useless” in tests by the UK Consumer magazine Which ? and according to a review of scientific studies.
Mosquitoes are weak fliers and an electric fan can interfere with them. Thus an electric fan can also help to ward off mosquitoes. But we must consider other health hazards of having a fan turned on all night !
Bed Nets and Window Screens
In order not to get bitten by mosquitoes, it is much better to sleep under fine-meshed mosquito-nets. It is recommended that such nets be used especially in the children's room, and on a baby's crib, since the toxic products from Vape-mat and mosquito coils affect young children even more than adults. There is a need to develop a bed-net culture in the country and also to make provision for screened windows when houses are built. In the long run this should prove to be a worthwhile investment. This will help decrease the amount of chemical products used to ward off mosquitoes in the home, be they mosquito coils, Vape-mats, or aerosols. People must never forget that all insecticides are poisons and that, whatever certain 'experts' may claim, there is no such thing as a safe insecticide. However, we agree that some insecticides are more toxic than others and may thus be more dangerous for human and animal health.