Abram and Sarai in Egypt

Genesis 12:10-20 - Now there was a famine in the land, and Abram went down to Egypt to live there for a while because the famine was severe. As he was about to enter Egypt, he said to his wife Sarai, "I know what a beautiful woman you are. When the Egyptians see you, they will say, 'This is his wife.' Then they will kill me but will let you live. Say you are my sister, so that I will be treated well for your sake and my life will be spared because of you."

When Abram came to Egypt, the Egyptians saw that she was a very beautiful woman. And when Pharaoh's officials saw her, they praised her to Pharaoh, and she was taken into his palace. He treated Abram well for her sake, and Abram acquired sheep and cattle, male and female donkeys, menservants and maidservants, and camels.

But the LORD inflicted serious diseases on Pharaoh and his household because of Abram's wife Sarai. So Pharaoh summoned Abram. "What have you done to me?" he said. "Why didn't you tell me she was your wife? Why did you say, 'She is my sister,' so that I took her to be my wife? Now then, here is your wife. Take her and go!" Then Pharaoh gave orders about Abram to his men, and they sent him on his way, with his wife and everything he had.

How did the Pharaoh know that his problems were caused by what Abram had done regarding Sarai? Did God tell him? Did the Pharaoh's wise men figure it out? Did someone spill the beans about Sarai and they just guessed (correctly) that she was the source of the problem? Were they able to deduce anything from the fact that only the Pharaoh and his household were affected?

What were the diseases? Were they life-threatening? Were there any fatalities? Who was included in "his household"? All of his servants and close government workers? Only his immediate family (which could have been quite large)?

It seems like it took some time for all of this to happen -- the diseases to develop and the determination of whose fault it was. (It's interesting that they even considered pinning the blame for the diseases on a specific person instead of something purely medical.) I think it took time because it says Abram was able to increase his wealth while living there. If all this happened over a few days or weeks, how could Abram have had time to become profitable?