The Atenists at Avaris objected. In an attempt to demonstrate their numbers, and their solidarity, they decided to engage in a large-scale act of civil disobedience. So they collected as much animal blood as possible, and then in one night, they dumped it all into the Nile, such that when Horemheb awoke, he saw a river running red with blood, suggestive of the scale of the carnage that would result if he did not heed the demands of the Atenists. This was recorded as the 1st
Unfortunately, this wasn't the healthiest thing to do. Animal blood doesn't keep well, and the bacteria so germinated don't just go away when flushed downstream. The frogs came out of the river in search of other sources of water (2nd
and many of them died. Then the land was overrun by gnats,3
lice, and flies,4
whose population is the responsibility of the frogs to control (3rd
Plagues). The insects turned to livestock as their only source of moisture. The immune systems of the animals had been weakened by dehydration, making them more vulnerable to diseases spread by the insects, especially as the insects continued to feed even on sick animals (5th
But the worst was yet to come. Some insects feed on both animals and people, including the fleas that can carry bubonic plague (6th
The situation might have been exasperated by an epidemic of influenza, brought on by the practice of keeping pigs and ducks in close proximity.8
The response of the people, under the circumstances, was appropriate.
While Egyptian medical practices were the most advanced in the world at the time, these specific practices haven't been found in any Egyptian document. So this information was lost to the Egyptians due to the damnatio memoriae, while the Hebrews preserved it. Regardless, the mayhem was enough to the get attention of the pharaoh.