This WHO laboratory manual provides the most up to date methods and procedures for the laboratory identification of yellow fever virus infection in humans. It provides guidance on the establishment and maintenance of an effective laboratory providing routine surveillance testing for yellow fever, which operates within the WHO coordinated Global Yellow Fever Laboratory Network (GYFLaN) capable of providing confirmation of yellow fever infection reliably and timely. This second edition supersedes the first edition of the 2004 WHO manual for the monitoring of yellow fever virus infection.