Emerging infectious diseases in Africa in the 21st century.

Many infectious diseases have emerged or reemerged in Africa in the 21st century. Some of them are associated with newly discovered microorganisms such as Rickettsia felis and Tropheryma whipplei; others are known, historical diseases such as plague and cholera. In addition are diseases related to previously known microorganisms which recently have been involved for the first time in massive outbreaks with worldwide impacts (such as Ebola virus, Zika virus and Chikungunya virus). Research on emerging infectious diseases needs to be identified as a priority.