You're definitely right that Ebola is far more likely to come from air travel, but other diseases are certainly a concern with illegal immigrants. Sanitation and vaccinations are abysmal in Central America, so it isn't surprising that illegal immigrants would bring diseases.
Those who emigrate legally are required to have a physician exam for communicable disease. After all, Ellis Island was a thing for a reason.
I have no issues with him reporting the actual documented diseases that have been treated at hospitals, it was his saying Ebola could come in with an illegal African immigrant that I take issue with. That's a sensationalist claim and is no more than a scare tactic. Any immigrant can be carrying a disease, so why not reform the immigration laws so that more immigrants are actually using the border crossings instead of trying to sneak in using deadlier routes?
Nice scare tactic there. I highly doubt that someone who lives in an Ebola prone area is going to be able to afford getting to Mexico and then afford be smuggled across. Ebola's biggest chance to get to the US is someone flying in from an active outbreak area immediately after contracting it and then not having symptoms for 3 weeks.