Which quote from When Birds Get the Flu by John DiConsiglio provides the best idea for an additional source to research for more information on diseases?

Dr. Kumnuan Ungchusak raced his jeep through the countryside of Thailand. He's a health official in Thailand.

Since then, the CDC has been active throughout the world, following infections such as smallpox, polio, tuberculosis, AIDS, and SARS.

The next step for Dr. Dowell and his colleagues was to determine how mother and daughter had caught the flu—and if they’d passed it on to others.

The pandemic affected everyone—and spread everywhere. Outbreaks swept through North America, Europe, Asia, Africa, Brazil, and the South Pacific.