>- when the pets are properly diagnosed and confirmed to have parasites, the appropriate drugs don't seem to have a problem riding these pets of their parasites.
Sufficient amounts of the appropriate drugs can kill the parasites, however, almost all of these drugs will damage the liver and other organs. I am well aware of how well these drugs work. Also, I am aware that one of my dogs was blind by 11 years of age from these drugs.
In addition, he was not as smart as he had been. He also developed severe joint problems. All of these issues were premature. There are prices to pay for using any of these drugs.
>- why it's so much harder for humans to get test confirmation and somehow parasites in humans are able to adapt and evade drugs
The answer follow the next statement.
>- why do vets and labs seem to have no problem confirming parasites in pets?
Because they test and examine on the spot. If they don't find something, they look again, immediately. The drugs are prescribed in higher doses for animals than for humans because of the potential for organ damage and long term issues.