Schaffner said that even apparently tidy hotel rooms can be a hotbed for the bugs.
"When you travel, you stay in a lot of strange beds," he said. "I'm pretty sure I had one experience of bedbug bites in my travels, and it was in a very decent hotel. A lot of this has to do with who was there before you."
The bad news is that as long as you are staying in a bed that is not your own, it is hard for you to control the level of bedbugs in your vicinity as you travel.
Fortunately, research has shown that though bedbug bites can spread disease, such diseases from these bites are rare.
"It's not an event that I would be concerned about," Schaffner said.
OK, we know we said five infections. But what story about travel illness could be complete without a mention of Montezuma's revenge?
Both Schaffner and Freedman agreed that travel diarrhea is perhaps the most common -- and one of the least pleasant -- vacation-related afflictions most travelers will be likely to encounter.
"This is one of those illnesses where if you have it, you're afraid that you're [not] going to live," Schaffner said.
The source can be any one of a number of microscopic bugs, most of which are viral in nature.
Schaffner said that travelers may be particularly at risk if they are traveling to a developing country.
"When traveling there, the admonitions about what you eat and drink become very, very important," he said. "Don't eat it unless it can be peeled or cooked."
Bottled water is a good idea. And cold food is probably a bad one -- even if it is a dish commonly believed to be a healthy one.
"In the words of my mentor, 'You can only sterilize salad with a blowtorch,'" Schaffner said.
As long as you're packing the bottled water, Schaffner recommended throwing in a few condoms as well, as wild vacations often provide ample opportunities for some to contract any one of a host of sexually transmitted diseases.
But perhaps the best thing you can do for yourself is to prepare for your trip by seeing a specialist after you buy your tickets -- but before you board your flight.
"My recommendation is always that people should see not just their primary care physician before they travel, but also a specialist at a traveler's health clinic prior to their trip," Freedman said.
Jenny Chan contributed to this report.