U.S. State Department Travel Information Web Site
A sire maintained by the U.S. government which features international travel updates, information about individual countries and specific information on handling crises and emergancies whicle traveling internationally is located here: https://travel.state.gov/content/travel/en/international-travel.html
U.S. State Department Travel Update Program
Passport and travel documentation requirements
Centers for Disease Control
World Health Organization
Sherpa.com - third party travel documentation and requirement information
Wikitravel.org - third party information on international destinations