Information from the US GOVERNMENT & CDC about diseases carried by insects & critters:
QUOTE: Ticks, mosquitoes, lice, fleas. These ancient pests continue to cause sickness and death worldwide. Here in the United States, it's increasingly important for everyone to know the basics: what insects are a problem and why, how to keep them away, and what to do if they bite.
US Map of Blood donors found with West Nile