Naruto visits Sakura, who is caring for Tsunade. Sakura recalls an incident that took place three years before, in which she collapsed from symptoms that resembled a disease caused by a mysterious virus.
Naruto Shippuden 184: Deploy! Team Tenten
Naruto Shippuden 185: Animal District
Naruto Shippuden 186: Ah, the Medicine of Youth
Naruto Shippuden 187: Gutsy Master and Student: The Training
Naruto Shippuden 188: Record of the Gutsy Ninja Master and Student