City records 93pc less dengue cases from last year
At a time when the Aedes mosquito has brought apprehensions in the neighbouring district of North 24 Parganas, Kolkata is heaving a sigh of relief.
Fact- Mosquitoes of different species are as different from each other as a lion is from a housecat. They have different behaviour, very different preferences of what they want to eat and where they might live. Urban species don’t do well in the country and some species thrive only in one specific region. Which mosquitoes like your environment can have an effect on the types of diseases you’re exposed to.
Fact- There are over 3,000 mosquito species worldwide, but only a couple of hundred are important medically. Most species of mosquito don’t even bite humans — some prefer other animals like amphibians, birds, horses and reptiles. Specific species carry specific diseases: For example, West Nile virus and St. Louis encephalitis virus come from the genera Culex. Chikungunya, dengue and yellow fever are carried by Aedes mosquitoes. Zika is spread by Aedes agypti or Aedes albopictus mosquito, Malaria is transmitted by species of the Anopheles genus.
Fact-While mosquitoes breed in water, droughts are some of the most disease promoting. The water may be less but it is dirtier and therefore appealing to mosquitoes. The lack of water sources means that mosquitoes and birds —who carry many of the mosquito-borne illnesses that affect us — are crowded together to share the resource.
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Fact-Only the females bite as they require the protein in our blood to produce their eggs. Males feed on other sources, such as flower nectar.
Fact-No. Mosquitoes are not attracted to people with more blood sugar. Researchers have found that mosquitoes have a love of carbon dioxide, lactic acid and certain strains of bacteria that some people have in higher concentrations. Some people have more carbon dioxide. Some sweat more. People who do heavy exercise make themselves more attractive to mosquitoes due to a potent combination of sweat, carbon dioxide, and lactic acid a compound found in sweat. This means that you’ll be more likely to get bitten if you sit outside after a run. Scent can also play a role.
Fact-No, the type makes no difference. Mosquitoes bite people because they require protein for breeding, not sugar. Some facets of a human’s genetics, such as skin bacteria, may have an effect, but blood type is not one of these factors.
Fact- The bites show up more on fair people, but all colours get the same number of bites.
Fact- Mosquitoes prefer larger people to smaller ones. Adults will be bitten more than children, and men more than women. This is probably because larger people emit higher quantities of carbon dioxide and body heat, and provide more surface area for feasting.
Fact-True. Pregnant women give off more heat and carbon dioxide.
Fact-There is no scientific or anecdotal data to suggest that they have any effect.
Fact-A study in Burkina Faso has found that beer consumption increases the human’s attractiveness to mosquitoes.
Fact- Avoiding the outdoors at certain times a day, especially early evenings, is one of the ways suggested to avoid exposure to bites. Staying inside with doors and windows shut, will lower your risk. But mosquitoes can be a problem inside. Some, especially the Aedes aegypti mosquito, live in nooks and crannies in homes and gardens. Some mosquitoes breed in boiler rooms and potted-plant containers. So in high risk areas, even if the air conditioning is on, the best thing to do is sleep under nets.
Fact-While mosquitoes like warm and marshy swamps and wetlands, removing these will not have any effect on mosquito populations or mosquito borne diseases. Many mosquitoes are much more comfortable in human habitats. Aedes aegypti live with humans as it is easier to find blood. Females lay their eggs in artificial containers with a bit of standing water – flower pots, vases, tires, buckets, planters, toys, birdbaths, empty garbage cans, lids. That is why it is vital to check your house, garden and neighbourhood for these kinds of containers. Empty them, turn them over, dry them out. Empty and refresh water in birdbaths and fountains at least once a week to keep mosquitoes from maturing.
Fact-Not true anymore. Research shows that mosquito populations increase with higher spring soil moisture levels-heavy snowfall, snowmelt and spring rain all provide sufficient standing water to allow the breeding of mosquitoes, even in typically “dry” areas.
Fact- While bats are extremely useful insect eaters, mosquitoes are far too small to interest them. They eat them but not in such large quantities, as the energy they need to catch them outweighs the food benefit.
Fact- Grandmother’s remedies, that a bowl of water with a few drops of liquid soap, a spray of Listerine or half a lemon stuffed full of cloves will keep mosquitoes away, are unfortunately not really true. Citronella candles have no effect outside the immediate area of the candle. The only way these candles can repel mosquitoes is by creating smoke, because insects don’t like smoke. Any candle will have the same effect as citronella candles. Citronella is a weak repellent — the plant needs to have its leaves crushed for any effect. Citronella oil may have some effect. So might lavender and peppermint oil, but very little. Listerine contains traces of eucalyptol, but actual eucalyptus-based mosquito repellents contain the compound in concentrations as high as 75 percent whereas the eucalyptol in mouthwash is usually below 1 percent, which means if it works at all it isn’t going to work very well or for very long. If you want to sit outside, set up a large fan. Mosquitoes have a hard time flying in a breeze.
Fact- Research published by the Centers for Disease Control and Prevention shows that products containing oil of lemon eucalyptus, whose active ingredient para-menthane-diol is derived from the eucalyptus tree, can be effective. But most botanical formulations require frequent reapplication-usually every 10 to 20 minutes.
Fact- Some species such as the Culex tend to attack after dusk. Others, including Aedes aegypti, bite by day. Some bite at dusk and dawn.
Fact-Controversial. Many scientists claim that colours don’t affect mosquitoes. Others claim that mosquitoes are more attracted to dark colours. Mosquitoes are attracted to heat. So, since dark colours absorb more heat, mosquitoes could be attracted to them.
Fact- Many flying insects, including moths, mosquitoes, and many flies, find the glow of artificial lights irresistible. So, the answer to our initial question is yes. But most lights generate heat and it is the heat that attracts mosquitoes.
Fact- The size of a mosquito bite welt has nothing to do with the amount of blood drawn by a mosquito. It depends on how your immune system responds to the mosquito’s saliva that’s been injected into your skin.
Fact-Mosquitoes don’t have teeth at all. They have a needle like hose attached to their mouth which has a tip of 47 sharp edges that make it easier for a mosquito to punch a hole in your skin and suck up the blood.
Fact-After mosquitoes have filled their bellies with blood, they have to excrete something out of their body to be able to fly. It’s not urine. The Anopheles mosquitoes excrete a plasma fluid. Others excrete fluid waste.
Fact-Totally false. They have no effect at all and are just marketing gimmicks.
Fact-Most commercial repellents contain DEET or Diethyl-meta-toluamide as their main insect-repelling ingredient. DEET works by blocking the receptors on their antennae that allow them to hone in on human beings.
Fact- I hate the idea of using chemicals, but this has been proven to keep away mosquitoes and there is a safety limit for its use on lotions or other products. Developed by the US Army in 1946, DEET was registered for human use in 1957 and has been found to be safe when applied according to label instructions. Do not ingest or inhale or apply over cuts, wounds or irritated skin. Another weaker option is Avon SkinSo-Soft. Its formula contains picaridin, a chemical that resembles the natural compound found in the plants used to produce black pepper, and IR3535 (a chemical of the naturally occurring amino acid B-alanine). But it needs to be applied every 20 minutes or less.
Fact- No. Sunscreens are intended for generous and frequent use while DEET is intended for less frequent use. Blending DEET with a sunscreen decreases the efficacy of both compounds.
(To join the animal welfare movement, contact gandhim@nic.in, www.peopleforanimalsindia.org)
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