Travel warnings (or travel advisories, a common euphemism that normally describes simple information) are issued by governments and sometimes international organizations such as the WHO to inform potential travellers abouts the risks of travelling to certain countries or regions. The risks in question are:

The warnings have different levels of severity which can be broadly categorized as:
  • Mild: If you go there, be careful and take precautions (e.g. inoculation). If it's just a vacation, you should probably reconsider.
  • Severe: Don't go there unless you really have to. We've warned you.
  • Evacuation: Absolutely don't go there, and if you're already there, leave immediately (usually some military evacuation service is offered at this point).