Answer the following question given this paragraph: 

The first case of West Nile virus in North America occurred in 1999. Within just a few years, the virus had spread throughout most of the United States. Birds as well as humans can be infected with the virus. Birds often fly long distances. This is one reason why West Nile virus spread so quickly.


Q: Where did west nile first appear?

 Choices:

- Central America

- North Africa

- Southeast Asia

- north america

A:
north america
