Mosquitoes have all but vanished from parts of the United States this summer, and residents in states like Minnesota say they cannot remember a season this quiet. A historic drought sweeping through the West and Midwest has cut mosquito populations by as much as 50 to 70 per cent in some regions.

Mosquito levels are down 50 percent across Western and Midwest states - but the West Nile virus caseload has hit a 22-year high

Mosquitoes have all but vanished from parts of the United States this summer, and residents in states like Minnesota say they cannot remember a season this quiet. A historic…