Time to tackle the mono question. Here's an article from the tennis press bemoaning the "problem" of mononucleosis in tennis. Here's another article about tennis and mono/glandular fever. Both fail to make any comparisons with other sports. So, I decided to do their work for them. Here's what 20 minutes on Google can get you regarding cyclists and glandular fever:
1. David Millar: 2002 mononucleosis. Fyi: Busted in 2004 for doping, admits using EPO in 2001 and 2003.
2. Michael Rasmussen: 2010 "glandular fever". Fyi: Suspended for missing doping tests in 2007. Investigated by Italian authorities in 2011.
3. Damiano Cunego: 2005 "glandular fever". Fyi: Questioned in 2011 by Italian authorities as part of a doping investigation, including EPO.
4. Bart Wellens: 2009 "glandular fever". Fyi: Investigated for doping in 2006, cleared in 2009; investigated again in 2012; and apparently cleared again.
5. Michael Rogers: 2007 & 2011
6. Philip Deignan: 2006
7. Glenn O'Shea: 2010
8. Dani King: 2010
9. Thorwald Veneberg: 2006
10. Jonathan Tiernan-Locke: 2005
11. Allan Davis: 2011
12. Cameron Wurf: 2009
Well, there it is. Oh, and there's also research showing that Epstein–Barr virus is present in higher levels in athletes. There's another study here. And here's a piece about infectious disease in athletes that states "Exercise improves immunity at moderate intensity but impairs immune function at extremes of duration and intensity." There's a similar article here.
If only the tennis media could put just a little effort into research...oh yeah...nevermind. After all, these are the same people who claim tennis anti-doping efforts are among the most stringent in sports.