In the last week the number of US deaths from West Nile Virus has more than doubled!

States from California to the Carolinas have reported cases of the mosquito-born illness, that has several manifestations, but which is known for targeting the brain and central nervous system.

Almost half the reported cases have occurred in the southern state of Texas and in Dallas County the authorities have been tackling the problem by spraying insect repellent from large tanks on the back of pick-up trucks and from specially converted aircraft.

Dallas County has also launched an extensive West Nile education campaign, even stopping cars to hand out flyers with prevention information. 

The weird thing about West Nile is that the vast majority of people who get the mosquito-born disease never know it - they have no symptoms - and don't get sick.

Eliminating standing or stagnant water from around homes is being recommended as the best way to reduce risk because that's where mosquitoes breed.

In Evansville, Indiana, the local Audubon Society is promoting a slightly more environmentally friendly approach to stopping the mosquitoes.

A large chimney stack can be seen emerging from the hop of hedgerows.  

It provides a home for Chimney Swifts ... a bird that loves to eat mosquitoes!  

West Nile Virus is found in temperate and tropical areas and was first identified in Uganda back in 1937.

Those tracking cases in the US like the Centers For Disease Control and Prevention say 2012 could be the worst year for West Nile in the US since it first appeared here in the late 1990s.