Why does the Torah insert the word "Kol Choli"?
Ramban and Seforno: Even illnesses that come via natural causes.
What are "Madvei Mitzrayim ha'Ra'im"?
Seforno: They are 'contagious maladies'.
Why does the Torah see fit to mention "Madvei Mitzrayim ha'Ra'im"?
Ramban #1: To teach us that Hashem will place all those maladies on our enemies just as He placed them on the Egyptians.
Ramban #2: To insinuate that if we don't observe the Mishpatim, He will place them on us.
As the Pasuk writes in the Tochachah, in 28:9.