About 20 years ago I got a dog from the pound and she had the early stages of heartworm, which I knew nothing about until the vet explained it. At the time, one thing that he showed me was a map of the of the United States from Canada to Mexico, and the Atlantic to the Pacific oceans with a plastic overlay showing both heartworm and Lyme disease. The map itself showed their much smaller existences decades before, the 1960s, and the overlay showed the difference and their massive spread by 1990 when he showed it to me. The first thing that I thought of was the ban on DDT. Now, before anyone or everyone jumps me, I知 not saying that DDT should or should not have been banned. I知 just saying that given what the map showed as far as mosquito (heartworm) and tick (Lyme disease) showed in the 1960s and how they had spread so drastically by 1990 throughout the country, the timing of the ban would suggest a direct correlation, good or bad. Since then, other less poisonous and lethal pesticides have been introduced and banned themselves, such as Dursban, and again, I知 not saying good or bad, but I知 willing to bet that someone can map it out using a time frame. Good or bad, I知 betting that there is a direct correlation without trying to start any arguments.
46 m, best of luck and health to your wife, yourself, everyone else.