Showing posts with label dengue fever. Show all posts
Showing posts with label dengue fever. Show all posts

Saturday, 8 July 2023

Mosquitoes

 

Mosquitoes

Images courtesy of Wikimedia Commons

The insistent whining like a tiny, merciless drill, edging closer in the stillness of the night disturbs and demands attention. The perpetrator cannot be seen until it’s upon you and sampling your blood.

What good are mosquitoes? What purpose do these vampires of the insect world serve other than to annoy, irritate and bite?

This question will have been asked a million times by people suffering the attentions of this little insect. The answer sounds apologetic – they are important pollinators for thousands of plant species and they are also an essential part of the food chain, providing sustenance for a variety of animals, like bats, birds, fish, reptiles and other arthropods. Arthropods fall roughly into four categories – insects, myriapods like centipedes and millipedes, arachnids (spiders) and crustaceans like prawns and crabs.

Since they lay their eggs in standing water, mosquito eggs and larvae provide food for fish, amphibians and the larvae of other insects, like dragonflies. Notwithstanding their role as food for others, they are mainly infamous for their function in transmitting diseases. The two that come most readily to mind are malaria and dengue fever but they also carry various encephalitic viruses, yellow fever, and filariasis, which can lead to elephantiasis. They are vectors for several other nasty afflictions, too, so it’s little wonder they are universally despised.

Apart from blood they also feed on flower nectar and their larvae consume algae and other bacterial matter in the water in which they live. Most adults live for two to three weeks.

When searching for a blood meal, they use sight, taste, heat and smell. Mammals breathe in oxygen and exhale carbon dioxide which mosquitoes can detect from thirty feet away.

Malaria was historically endemic in marshy areas in UK, causing many deaths between the 15th and 19th centuries. It was known by various names, like marsh fever, the ague or intermittent fever and occurred in low-lying areas of Essex, Kent, Sussex, the Somerset Levels, Holderness in the East Riding of Yorkshire and the Ribble Valley in Lancashire. The decline of locally acquired disease was attributed to land drainage and improved sanitation, hygiene and housing.

UK mosquitoes do not now transit deadly diseases so we have cause to be thankful for fairly large mercies!

The mosquito gave its name to the twin-engined de Havilland DH.98 Mosquito, which was introduced during the Second World War. It was nicknamed ‘The Wooden Wonder’ because it was constructed mainly of wood.


A Royal Air Force de Havilland Mosquito in flight, 30th September, 1944

 It was also known as ‘Mossie’, but Lord Beaverbrook, then Minister of Aircraft Production, called it ‘Freeman’s Folly’ because Air Chief Marshal Sir William Freeman defended the design concept against orders to scrap it. In 1941 it was one of the fastest operational aircraft in the world, fulfilling many roles – pathfinder and photo-reconnaissance among others - in addition to its original proposed role as an unarmed fast bomber.