Is it true that Africa and Asia are separated only by the Suez Canal?

Also by the Red Sea.
It might also be noted that for gepolitical reasons the Sinai peninsula is often considered as a part of Africa.

http://upload.wikimedia.org/wikipedia/commons/3/3a/AfricaCIA-HiRes.jpg

It should of course be 'geopolitical'. And maybe you should also say that Africa and Asia are separated by the Isthmus of Suez and not just by the Suez Canal.

Here is a quote:
Africa is joined to Asia at its northeast extremity by the Isthmus of Suez (transected by the Suez Canal), 163 km (101 miles) wide.[5] (Geopolitically, Egypt's Sinai Peninsula east of the Suez Canal is often considered part of Africa, as well.

https://en.wikipedia.org/wiki/Africa

Still, in 1967 only when the Israelis managed to cross the Suez Canal did they sing "Avarnu l'Africa" ("we've crossed over to Africa"). Though, technically speaking, the Levant (Sinai, Israel, Lebanon) is on the African tectonic plate....

Author's second reference confirms that Africa and Asia are "joined" by the Isthmus of Suez, which I would have thought meant the opposite of "separated".
But as the Suez Canal transects the Isthmus, then evidently the two continents are indeed separated by the canal.
https://en.wikipedia.org/wiki/Africa#Geography