Albert Barnes Commentary Exodus 9:3

"behold, the hand of Jehovah is upon thy cattle which are in the field, upon the horses, upon the asses, upon the camels, upon the herds, and upon the flocks: [there shall be] a very grievous murrain." — Exodus 9:3 (ASV)

A very grievous murrain - Or “pestilence;” but the word “murrain,” that is, “a great mortality,” exactly expresses the meaning. This terrible visitation struck far more severely than the preceding, which had caused distress and suffering; it attacked the resources of the nation.

The camels - These animals are only twice mentioned, here and (Genesis 12:16), in connection with Egypt. Though camels are never represented on the monuments, they were known to the Egyptians, and were probably used on the frontier.