Found at the lowest point of a large drainage area, these seasonal, marsh-like ponds collect and store water from rain and runoff. Unlike vernal pools, playas generally fill when temperatures are unsuitable for plant growth, and often the water is salty, alkali or both.
source- google
West Nile is carried by mosquitoes. Mosquitoes use bodies of water, such as ponds, to lay their eggs. If you live near a pond, there are going to be a lot of mosquitoes around you, thus making you more susceptible to West Nile.
The answer is convergent continental-continental
One would most likely find a glacier-carved lake in Patagonia
