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Wednesday, May 21, 2014

mosquito menace - from Triplicane to UK ..... and guppies controlling them

The guppy (Poecilia reticulata), also rainbow fish, is one of the world's most widely distributed tropical fish and also the popular aquarium fish. I have been fascinated by the guppies of Kairavini Pushkarini ……. Present day youth may not know that there existed open wells at every house, Corporation personnel would visit each house dispensing handful of guppies in to the well.  photo credit : guppies.com

Away ‘mosquito’ menace is felt everywhere.  Can you name the mosquito that bites Aiswarya Rai in Enthiran ?   The mosquitoes are a family of small, midge-like flies: the Culicidae. Although a few species are harmless or even useful to humanity, most are considered a nuisance because they consume blood from living vertebrates, including humans.  When half-asleep, a pierce to one’s skin, leaving behind an itchy red welt and possibly even a serious illness.  Possibly only some are attacked while some are unfazed. Could it be that mosquitoes prefer to bite some people over others? ~ perhaps yes, mosquitoes do exhibit blood-sucking preferences ! males do not bite people, females do as they  need human blood to develop fertile eggs.  The females of many species of mosquitoes are blood-eating pests. There were theories that mosquitoes will not live in coastal places due to salinity; that the would not be present in top floors of high rise building.  There used to be many jokes in Ananda Vikadan, Kumudam and other popular magazines of the mosquito menace especially Mambalam, making it area-specific.  A couple of decades ago, there existed a team called ‘Mambalam Mosquitoes’ aptly representing the locality. 

Life has changed since – now you find mosquitoes everywhere be it – Triplicane, Mylapore, Medavakkam, Madipakkam – name any area – most popular myths have been exploded – they are found on every floor of very tall structures too. All mosquitoes must have water in which to complete their life cycle. This water can range in quality from melted snow water to sewage effluent and it can be in any container imaginable. Mosquitoes  lay their eggs in places such as tree holes that periodically hold water, tide water pools in salt marshes, sewage effluent ponds, irrigated pastures, rain water ponds, etc. Each species therefore has unique environmental requirements for the maintenance of its life cycle.

~ now this is no post on mosquitoes of Chennai or its neighbourhood -  but far away in the UK …  changes to UK urban areas provide habitats for mosquitoes, including species known to spread malaria and West Nile virus, a study suggests. Warmer ambient temperatures and more water containers in gardens are bringing mosquitoes into closer contact with people, say scientists. Based on a survey of UK local authorities, reports of mosquito bites over the last 10 years are 2.5 times greater than in the 10 years up to 1996. NHS Direct statistics show 9,061 calls in England complaining of bites and stings from early May this year to now - up nearly 15% from last summer. Not all bite complaints are due to mosquitoes - many can be attributed to bedbugs, midges and fleas. But conditions in the UK, particularly in southeastern England, are increasingly hospitable to mosquitoes.

The Health Protection Agency has organised the Mosquito Recording Scheme to look into where and how mosquitoes live and breed. And the Chartered Institute of Environmental Health, with help from the HPA, has created Mosquito Watch, a voluntary reporting system geared towards collecting and analysing various specimens. Not only do mosquitoes swarm over pools of standing water, including bowls left outside for pets, they appear under man-hole covers and even travel on London's Tube network. But while mosquitoes transmit deadly diseases in many parts of the world, they do not cause major harm in the UK.

Malaria in England had effectively died out by the 1950s, mostly due to the draining of much of the marshland where mosquitoes bred. But because of the growth of global travel, the number of imported cases of the disease in the UK has risen, with nearly 2,000 a year today. In many cases, live mosquitoes have been found on aircraft, or travelling in luggage, having been transported from countries with malaria. On rare occasions, people may even have contracted malaria in Europe and North America, dubbed "airport malaria".

It is stated that a severe drought and subsequent hosepipe ban in the spring of 2012 across southern and eastern England led to reports of hugely inflated sales of water butt containers. The number of water containers continues to grow as households look to save money and water…. Changing behavioural pattern also has been observed as - more than 30 different mosquito species have been recorded in the UK, most of which are resident all year round.

Getting back to Triplicane, those days the guppies were dispensed in wells as they would eat larvae of mosquito and can effectively control mosquito growth.   Guppies were found to be highly adaptable and thrive in many different environmental and ecological conditions.  Though not native here, guppy fish have been introduced to many different countries on every continent except Antarctica. Sometimes this has occurred accidentally, but most often as a means of mosquito control. The mosquito in Enthiran that would bite Aishwarya Rai ~ after which Robo Rajini would run, find it in a slum, catch and present it – was named ‘Ranguski’ – perhaps the nickname of my favourite writer Sujatha, whose story was filmed by Shankar.

With regards – S. Sampathkumar

21st May 2014. 

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