I had no idea that tuberculosis was popular in London. The city is apparently called the TB capital of Europe and has one of the highest rates of the disease in the continent, five times higher than in the United States. The article I read said England was putting over $17 million into fixing the problem, but it just seemed odd to hear that a first-world country with nationalized healthcare could have such issues.
The English teeth thing I can almost understand. If you're an actor with bad teeth and people still think you're sexy, hey, you're sexy! As long as you can still eat food with the teeth, there probably aren't major health issues, but TB? I thought that was something out of a Charles Dickens novel. Not only does TB exist in London, but it's getting stronger, with a doubling of multi-drug resistant TB over the past fifteen years.
Advice for American tourists? Stay away from the poverty-sticken and those who seem to be coughing up a lung, especially if they look poor. If they look pale and feverish, that's also an excellent sign they might have the "white plague" and that you should head in the opposite direction.